Scalable One-Pot Fabrication of Carbon-Nanofiber-Supported Noble-Metal-Free Nanocrystals for Synergetic-Dependent Green Hydrogen Production: Unraveling Electrolyte and Support Effects

Electrocatalytic hydrogen evolution reactions (HER) are envisaged as the most promising sustainable approach for green hydrogen production. However, the considerably high cost often associated with such reactions, particularly upon scale-up, poses a daunting challenge. Herein, a facile, effective, and environmentally benign one-pot scalable approach is developed to fabricate MnM (M═Co, Cu, Ni, and Fe) nanocrystals supported over in situ formed carbon nanofibers (MnM/C) as efficient noble-metal-free electrocatalysts for HER. The formation of carbon nanofibers entails impregnating cellulose in an aqueous solution of metal precursors, followed by annealing the mixture at 550 °C. During the impregnation process, cellulose acts as a reactor for inducing the in situ reductions of MnM salts with the assistance of ether and hydroxyl groups to drive the mass production (several grams) of ultralong (5 ± 1 μM) carbon nanofibers ornamented with MnM nanoparticles (10-14 nm in size) at an average loading of 2.87 wt %. For better electrocatalytic HER benchmarking, the fabricated catalysts were tested over different working electrodes, i.e., carbon paper, carbon foam, and glassy carbon, in the presence of different electrolytes. All the fabricated MnM/C catalysts have demonstrated an appealing synergetic-effect-dependent HER activity, with MnCo/C exhibiting the best performance over carbon foam, close to that of the state-of-the-art commercial Pt/C (10 wt % Pt), with an overpotential of 11 mV at 10 mA cm-2, a hydrogen production rate of 2448 mol g-1 h-1, and a prolonged stability of 2 weeks. The HER performance attained by MnCo/C nanofibers is among the highest reported for Pt-free electrocatalysts, thanks to the mutual alloying effect, higher synergism, large surface area, and active interfacial interactions over the nanofibers. The presented findings underline the potential of our approach for the large-scale production of cost-effective electrocatalysts for practical HER.

Interfacial Electronic Interactions within the Pd-CeO2/Carbon Onions Define the Efficient Electrocatalytic Ethanol Oxidation Reaction in Alkaline Electrolytes

Porous Pd-based electrocatalysts are promising materials for alkaline direct ethanol fuel cells (ADEFCs) and ethanol sensors in the development of renewable energy and point-of-contact ethanol sensor test kits for drunk drivers. However, experimental and theoretical investigations of the interfacial interaction among Pd nanocrystals on supports (i.e., carbon black (CB), onion-like carbon (OLC), and CeO2/OLC) toward ADEFC and ethanol sensors are not yet reported. This is based on the preparation of Pd-CeO2/OLC nanocrystals by the sol-gel and impregnation methods. Evidently, the porous Pd-CeO2/OLC significantly increased membrane-free micro-3D-printed ADEFC performance with a high peak power density (Pmax = 27.15 mW cm-2) that is 1.38- and 7.58-times those of Pd/OLC (19.72 mW cm-2) and Pd/CB (3.59 mW cm-2), besides its excellent stability for 48 h. This is due to the excellent interfacial interaction among Pd, CeO2, and OLC, evidenced by density functional theory (DFT) simulations that showed a modulated Pd d-band center and facile active oxygenated species formation by the CeO2 needed for ethanol fuel cells. Similarly, Pd-CeO2/OLC gives excellent sensitivity (0.00024 mA mM-1) and limit of detection (LoD = 8.7 mM) for ethanol sensing and satisfactory recoveries (89-108%) in commercial alcoholic beverages (i.e., human serum, Amstel beer, and Nederberg Wine). This study shows the excellent possibility of utilizing Pd-CeO2/OLC for future applications in fuel cells and alcohol sensors.

Unmasking the Electrochemiluminescence Properties of Ternary Mn/Fe/Co Metals Doped Porous g-C3N4 Fiber-like Nanostructure

Graphitic-phase carbon nitride (g-C3N4) materials have exhibited increasingly remarkable performance as emerging electrochemiluminescence (ECL) emitters, owing to their unique optical and electronic properties; however, the ECL merits of porous g-C3N4 nanofibers doped with ternary metals are not yet explored. Deciphering the ECL properties of trimetal-doped g-C3N4 nanofibers could provide an exquisite pathway for ultrasensitive sensing and imaging with impressive advantages of minimal background signal, great sensitivity, and durability. Herein, we rationally synthesized g-C3N4 nanofibers doped atomically with Mn, Fe, and Co elements (Mn/Fe/Co/g-C3N4) in a one-pot via the protonation in ethanol and annealing process driven by the rolling up mechanism. The ECL performance of g-C3N4 with and without metal dopants was investigated and compared with standard Ru(bpy)32+ in the presence of potassium persulfate (K2S2O8) as the coreactant. Notably, g-C3N4 nanofibers doped with metal ions exhibited an ECL efficiency of 483% that was 4.83 times higher than that of Ru(bpy)32+. Mechanistic investigations unveiled that the g-C3N4 nanofibers possess a large surface area and, as a result, exhibit a reduced interfacial impedance within the porous microstructure. These factors contribute to the acceleration of charge transfer rates and the stabilization of charge carriers and excitons, ultimately facilitating the ECL process. This research endeavor may pave the way for a new hot research area and serves as a powerful tool for elucidating fundamental inquiries of ECL on one-dimensional g-C3N4 nanostructures.

Interfacial Engineering of Porous Pd/M (M = Au, Cu, Mn) Sponge-like Nanocrystals with a Clean Surface for Enhanced Alkaline Electrochemical Oxidation of Ethanol

The interfacial engineering of Pd-based alloys (i.e., PdM with distinct morphologies, compositions, and strain defects) is an efficient way for enhanced catalytic activity; however, it remains a grand challenge to fabricate such alloys in aqueous solutions without heating, organic solvents, and multiple reaction steps. Herein, we present a simple, aqueous-phase, one-step, and ultrafast approach for the interfacial engineering of surfactant-free porous PdM (M = Cu, Au, and Mn) nanocrystals with well-controlled spongy-like morphology and compositions. The electronic interaction in PdM nanocrystals and their effect on the alkaline electrochemical ethanol oxidation reaction (EOR) are investigated using XRD, XPS, and electrochemical tests. Notably, integrating M metals into Pd atoms results in upshifting the d-band center of Pd and subsequently modulating the EOR activity and stability substantially. The EOR mass activity (10.78 A/mgPd (6.93 A/mgPdCu)) of PdCu was 1.83, 3.09, 4.51, and 53.90 times higher than those of AuPd (5.90 A/mgPd (3.27 A/mgAuPd)), PdMn (3.48 A/mgPd (3.19 A/mgPdMn)), Pd (2.39 A/mgPd), and Pd/C (0.20 A/mgPd), respectively, besides substantial durability after 1000 cycles. This is due to the porous two-dimensional morphology, a low synergetic effect, higher interfacial interaction, and greater active surface area of PdCu, besides a high Cu content with more oxophilicity that facilitates activation/dissociation of H2O to generate -OH species needed for quick EOR electrocatalysis. The electrochemical impedance spectroscopy (EIS) reveals better electrolyte/electrode interfacial interaction and lower charge transfer resistance on PdCu. The EOR activity of PdCu porous sponge-like nanocrystals was superior to all previously reported Pd-based alloys for electrochemical EOR. This study indicates that binary Pd-based catalysts with less synergetic effect are preferred for boosting the EOR activity, which could help in manipulating the surface properties of Pd-based alloys to optimize EOR performance.

Self-Standing Pd-Based Nanostructures for Electrocatalytic CO Oxidation: Do Nanocatalyst Shape and Electrolyte pH Matter?

Tailoring the shape of Pd nanocrystals is one of the main ways to enhance catalytic activity; however, the effect of shapes and electrolyte pH on carbon monoxide oxidation (CO_Oxid) is not highlighted enough. This article presents the controlled fabrication of Pd nanocrystals in different morphologies, including Pd nanosponge via the ice-cooling reduction of the Pd precursor using NaBH₄ solution and Pd nanocube via ascorbic acid reduction at 25 °C. Both Pd nanosponge and Pd nanocube are self-standing and have a high surface area, uniform distribution, and clean surface. The electrocatalytic CO oxidation activity and durability of the Pd nanocube were significantly superior to those of Pd nanosponge and commercial Pd/C in only acidic (H₂SO₄) medium and the best among the three media, due to the multiple adsorption active sites, uniform distribution, and high surface area of the nanocube structure. However, Pd nanosponge had enhanced CO_Oxid activity and stability in both alkaline (KOH) and neutral (NaHCO₃) electrolytes than Pd nanocube and Pd/C, attributable to its low Pd-Pd interatomic distance and cleaner surface. The self-standing Pd nanosponge and Pd nanocube were more active than Pd/C in all electrolytes. Mainly, the CO_Oxid current density of Pd nanocube in H₂SO₄ (5.92 mA/cm²) was nearly 3.6 times that in KOH (1.63 mA/cm²) and 10.3 times that in NaHCO₃ (0.578 mA/cm²), owing to the greater charge mobility and better electrolyte-electrode interaction, as evidenced by electrochemical impedance spectroscopy (EIS) analysis. Notably, this study confirmed that acidic electrolytes and Pd nanocube are highly preferred for promoting CO_Oxid and may open new avenues for precluding CO poisoning in alcohol-based fuel cells.

ZnO-Doped gC3N4 Nanocapsules for Enhancing the Performance of Electroless NiP Coating-Mechanical, Corrosion Protection, and Antibacterial Properties

A carbon nitride (C₃N₄) nanomaterial has superior mechanical, thermal, and tribological properties, which make them attractive for various applications, including corrosion-resistant coatings. In this research, newly synthesized C₃N₄ nanocapsules with different concentrations (0.5, 1.0, and 2.0 wt %) of ZnO as a dopant were incorporated into the NiP coating using an electroless deposition technique. The nanocomposite coatings either ZnO-doped (NiP-C₃N₄/ZnO) or undoped (NiP-C₃N₄) were heat-treated at 400 °C for 1 h. The as-plated and heat-treated (HT) nanocomposite coatings were characterized by their morphology, phases, roughness, wettability, hardness, corrosion protection, and antibacterial properties. The results indicated that the microhardness of as-plated and heat-treated nanocomposite coatings was significantly improved after the incorporation of 0.5 wt % ZnO-doped C₃N₄ nanocapsules. The outcomes of electrochemical studies revealed that the corrosion resistance of the HT coatings is higher than the corresponding as-plated ones. The highest corrosion resistance is achieved on the heat-treated NiP-C₃N₄/1.0 wt % ZnO coatings. Although the presence of ZnO in the C₃N₄ nanocapsules increased its surface area and porosity, the C₃N₄/ZnO nanocapsules prevented localized corrosion by filling the microdefects and pores of the NiP matrix. Furthermore, the colony-counting method used to evaluate the antibacterial behavior of the different coatings demonstrated superior antibacterial properties, namely, after heat treatment. Therefore, the novel perspective C₃N₄/ZnO nanocapsules can be utilized as a reinforcement nanomaterial in improving the mechanical and anticorrosion performance of NiP coatings in chloride media, together with providing superior antibacterial properties.

Unraveling ultrasonic assisted aqueous-phase one-step synthesis of porous PtPdCu nanodendrites for methanol oxidation with a CO-poisoning tolerance

The tailored design of tri-metallic Pt-based porous nanodendrites (PNDs) is crucial for green energy production technologies, ascribed to their fancy features, great surface areas, accessible active sites, and stability against aggregation. However, their aqueous-phase one-step synthesis at room temperature remains a daunting challenge. Herein, we present a facile, green, and template-free approach for the one-step synthesis of PtPdCu PNDs by ultrasonication of an aqueous solution of metal salts and Pluronic F127 at 25 ℃, based on natural isolation among nucleation and growth step driven by the disparate reduction kinetics of the metals and acoustic cavitation mechanism of ultrasonic waves. The resultant PtPdCu PNDs formed in a spatial nanodendritic shape with a dense array of branches, open corners, interconnected pores, high surface area (46.9 m²/g), and high Cu content (21 %). The methanol oxidation reaction (MOR) mass activity of PtPdCu PNDs (3.66 mA/µg_Pt) is 1.45, 2.73, and 2.83 times higher than those of PtPd PNDs, PtCu PNDs, and commercial Pt/C, respectively based on equivalent Pt mass, which is superior to previous PtPdCu catalysts reported elsewhere, besides a superior durability and CO-poisoning tolerance. This study may pave the way for the controlled fabrication of ternary Pt-based PNDs for various electrocatalytic applications.

Unveiling the effect of shapes and electrolytes on the electrocatalytic ethanol oxidation activity of self-standing Pd nanostructures

Morphologically controlled Pd-based nanocrystals are the most efficient strategies for improving the electrocatalytic ethanol oxidation reaction (EOR) performance; however, their morphological-EOR activity relationship and effect of electrolytes at a wide pH range are still ambiguous. Here, we have synthesized porous self-standing Pd clustered nanospheres (Pd-CNSs) and Pd nanocubes (Pd-NCBs) for the EOR in acidic (H₂SO₄), alkaline (KOH), and neutral (NaHCO₃) electrolytes compared to commercial spherical-like Pd/C catalysts. The fabrication process comprises the ice-cooling reduction of Pd precursor by sodium borohydride (NaBH₄) and l-ascorbic acid to form Pd-CNSs and Pd-NCBs, respectively. The EOR activity of Pd-CNSs significantly outperformed those of Pd-NCBs, and Pd/C in all electrolytes, but the EOR activity was better in KOH than in H₂SO₄ and NaHCO₃. This is due to the 3D porous clustered nanospherical morphology that makes Pd active centers more accessible and maximizes their utilization during EOR. The EOR specific/mass activities of Pd-CNSs reached (8.51 mA/cm²/2.39 A/mg_Pd) in KOH, (2.98 mA/cm²/0.88 A/mg_Pd) in H₂SO₄, and (0.061 mA/cm²/0.0083 A/mg_Pd) in NaHCO₃, in addition to stability after 1000 cycles. This study affirms that porous 3D spherical Pd nanostructures are preferred for the EOR than those of 0D spherical-like and multi-dimensional cube-like nanostructures.

Correction: Pd/Ni-metal-organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range

[This corrects the article DOI: 10.1039/D2NA00455K.].

Non-Metal-Doped Porous Carbon Nitride Nanostructures for Photocatalytic Green Hydrogen Production

Photocatalytic green hydrogen (H₂) production through water electrolysis is deemed as green, efficient, and renewable fuel or energy carrier due to its great energy density and zero greenhouse emissions. However, developing efficient and low-cost noble-metal-free photocatalysts remains one of the daunting challenges in low-cost H₂ production. Porous graphitic carbon nitride (gCN) nanostructures have drawn broad multidisciplinary attention as metal-free photocatalysts in the arena of H₂ production and other environmental remediation. This is due to their impressive catalytic/photocatalytic properties (i.e., high surface area, narrow bandgap, and visible light absorption), unique physicochemical durability, tunable electronic properties, and feasibility to synthesize in high yield from inexpensive and earth-abundant resources. The physicochemical and photocatalytic properties of porous gCNs can be easily optimized via the integration of earth-abundant heteroatoms. Although there are various reviews on porous gCN-based photocatalysts for various applications, to the best of our knowledge, there are no reviews on heteroatom-doped porous gCN nanostructures for the photocatalytic H₂ evolution reaction (HER). It is essential to provide timely updates in this research area to highlight the research related to fabrication of novel gCNs for large-scale applications and address the current barriers in this field. This review emphasizes a panorama of recent advances in the rational design of heteroatom (i.e., P, O, S, N, and B)-doped porous gCN nanostructures including mono, binary, and ternary dopants for photocatalytic HERs and their optimized parameters. This is in addition to H₂ energy storage, non-metal configuration, HER fundamental, mechanism, and calculations. This review is expected to inspire a new research entryway to the fabrication of porous gCN-based photocatalysts with ameliorated activity and durability for practical H₂ production.

Pd/Ni-metal-organic framework-derived porous carbon nanosheets for efficient CO oxidation over a wide pH range

Metal nanocrystal ornamented metal-organic frameworks (MOFs) are of particular interest in multidisciplinary applications; however, their electrocatalytic CO oxidation performance over wide pH ranges is not yet reported. Herein, Ni-MOF-derived hierarchical porous carbon nanosheets (Ni-MOF/PC) with abundant Ni-N _x sites decorated with Pd nanocrystals (Pd/Ni-MOF/PC) were synthesized by microwave-irradiation (MW-I) followed by annealing at 900 °C and subsequent etching of Ni-MOF/C prior to Pd deposition. The fabrication mechanism comprises the generation of self-reduced reducing gases from triethylamine during the annealing and selective chemical etching of Ni, thereby facilitating the reduction of Ni-anchored MOF and Pd nanocrystal deposition with the aid of ethylene glycol and MW-I to yield Pd/Ni-N _x enriched MOF/PC. The synthetic strategies endear the Pd/Ni-MOF/PC with unique physicochemical merits: abundant defects, interconnected pores, high electrical conductivity, high surface area, Ni-deficient but more active sites for Pd/Ni-N _x in porous carbon nanosheets, and synergism. These merits endowed the CO oxidation activity and stability on Pd/Ni-MOF/PC substantially than those of Pd/Ni-MOF/C and Pd/C catalysts in wide pH conditions (i.e., KOH, HClO_4, and NaHCO₃). The CO oxidation activity study reveals the utilization of MOF/PC with metal nanocrystals (Pd/Ni) in CO oxidation catalysis.

Hierarchical Porous Carbon Nitride-Crumpled Nanosheet-Embedded Copper Single Atoms: An Efficient Catalyst for Carbon Monoxide Oxidation

Rational design of metal single-site embedded porous graphitic carbon nitride (P-g-C₃N₄) nanostructures exploiting maximum atom utilization is warranted to enhance the thermal CO oxidation (CO_Ox) reaction. Herein, a facile, green, one-pot, and template-free approach is developed to fabricate the hierarchical porous P-g-C₃N₄-crumpled ultrathin nanosheets atomically doped with copper single atoms (Cu-P-g-C₃N₄). Mechanistically, the quick protonation of melamine and pyridine under acidic conditions induces deamination to form melem, which is polycondensed under heating. The interconnected pores, high surface area (240 m²g^-1), and maximized exposed isolated Cu atomic active sites (1.8 wt %) coordinated with nitrogen atom P-g-C₃N₄ are the salient features of Cu- P-g-C₃N₄ that endowed complete conversion to CO₂ at 184 °C. In contrast, P-g-C₃N₄ only converted 3.8% of CO even at 350 °C, implying the electronic effect of Cu single atoms. The abundant Cu-nitrogen moieties can drastically weaken the binding affinity of the CO-oxidation (CO_Ox) intermediates and products, thus accelerating the reaction kinetics at a low temperature. This study may promote the fabrication of P-g-C₃N₄ doped with various single atoms for the oxidation of CO.

Pd-Nanoparticles Embedded Metal-Organic Framework-Derived Hierarchical Porous Carbon Nanosheets as Efficient Electrocatalysts for Carbon Monoxide Oxidation in Different Electrolytes

Rational synthesis of Co-ZIF-67 metal-organic framework (MOF)-derived carbon-supported metal nanoparticles is essential for various energy and environmental applications; however, their catalytic activity toward carbon monoxide (CO) oxidation in various electrolytes is not yet emphasized. Co-ZIF-67-derived hierarchical porous carbon nanosheet-supported Pd nanocrystals (Pd/ZIF-67/C) were prepared using a simple microwave-irradiation approach followed by carbonization and etching. Mechanistically, during microwave irradiation, triethyleneamine provides abundant reducing gases that promote the formation of Pd nanoparticles/Co-N_x in porous carbon nanosheets with the assistance of ethylene glycol and also form a multimodal pore size. The electrocatalytic CO oxidation activity and stability of Pd/ZIF-67/C outperformed those of commercial Pd/C and Pt/C catalysts by (4.2 and 4.4, 4.0 and 2.7, 3.59 and 2.7) times in 0.1 M HClO₄, 0.1 M KOH, and 0.1 M NaHCO₃, respectively, due to the catalytic properties of Pd besides the conductivity of Co-N_x active sites and delicate porous structures of ZIF-67. Notably, using Pd/ZIF-67/C results in a higher CO oxidation activity than Pd/C and Pt/C. This study may pave the way for using MOF-supported multi-metallic nanoparticles for CO oxidation electrocatalysis.

Vanadium Carbide (V4C3) MXene as an Efficient Anode for Li-Ion and Na-Ion Batteries

Li-ion batteries (LIBs) and Na-ion batteries (SIBs) are deemed green and efficient electrochemical energy storage and generation devices; meanwhile, acquiring a competent anode remains a serious challenge. Herein, the density-functional theory (DFT) was employed to investigate the performance of V₄C₃ MXene as an anode for LIBs and SIBs. The results predict the outstanding electrical conductivity when Li/Na is loaded on V₄C₃. Both Li_2xV₄C₃ and Na_2xV₄C₃ (x = 0.125, 0.5, 1, 1.5, and 2) showed expected low-average open-circuit voltages of 0.38 V and 0.14 V, respectively, along with a good Li/Na storage capacity of (223 mAhg^-1) and a good cycling performance. Furthermore, there was a low diffusion barrier of 0.048 eV for Li_0.0625V₄C₃ and 0.023 eV for Na_0.0625V₄C₃, implying the prompt intercalation/extraction of Li/Na. Based on the findings of the current study, V₄C₃-based materials may be utilized as an anode for Li/Na-ion batteries in future applications.

Porous spinel-type transition metal oxide nanostructures as emergent electrocatalysts for oxygen reduction reactions

Porous spinel-type transition metal oxide (PS-TMO) nanocatalysts comprising two kinds of metal (denoted as A_xB_3-xO₄, where A, B = Co, Ni, Zn, Mn, Fe, V, Sm, Li, and Zn) have emerged as promising electrocatalysts for oxygen reduction reactions (ORRs) in energy conversion and storage systems (ECSS). This is due to the unique catalytic merits of PS-TMOs (such as p-type conductivity, optical transparency, semiconductivity, multiple valence states of their oxides, and rich active sites) and porous morphologies with great surface area, low density, abundant transportation paths for intermediate species, maximized atom utilization and quick charge mobility. In addition, PS-TMOs nanocatalysts are easily prepared in high yield from Earth-abundant and inexpensive metal precursors that meet sustainability requirements and practical applications. Owing to the continued developments in the rational synthesis of PS-TMOs nanocatalysts for ORRs, it is utterly imperative to provide timely updates and highlight new advances in this research area. This review emphasizes recent research advances in engineering the morphologies and compositions of PS-TMOs nanocatalysts in addition to their mechanisms, to decipher their structure-activity relationships. Also, the ORR mechanisms and fundamentals are discussed, along with the current barriers and future outlook for developing the next generation of PS-TMOs nanocatalysts for large-scale ECSS.

Heteroatom-Doped Porous Carbon-Based Nanostructures for Electrochemical CO2 Reduction

The continual rise of the CO2 concentration in the Earth’s atmosphere is the foremost reason for environmental concerns such as global warming, ocean acidification, rising sea levels, and the extinction of various species. The electrochemical CO2 reduction (CO2RR) is a promising green and efficient approach for converting CO2 to high-value-added products such as alcohols, acids, and chemicals. Developing efficient and low-cost electrocatalysts is the main barrier to scaling up CO2RR for large-scale applications. Heteroatom-doped porous carbon-based (HA-PCs) catalysts are deemed as green, efficient, low-cost, and durable electrocatalysts for the CO2RR due to their great physiochemical and catalytic merits (i.e., great surface area, electrical conductivity, rich electrical density, active sites, inferior H2 evolution activity, tailorable structures, and chemical–physical–thermal stability). They are also easily synthesized in a high yield from inexpensive and earth-abundant resources that meet sustainability and large-scale requirements. This review emphasizes the rational synthesis of HA-PCs for the CO2RR rooting from the engineering methods of HA-PCs to the effect of mono, binary, and ternary dopants (i.e., N, S, F, or B) on the CO2RR activity and durability. The effect of CO2 on the environment and human health, in addition to the recent advances in CO2RR fundamental pathways and mechanisms, are also discussed. Finally, the evolving challenges and future perspectives on the development of heteroatom-doped porous carbon-based nanocatalysts for the CO2RR are underlined.

Cerium functionalized graphene nano-structures and their applications; A review

Graphene-based nanomaterials with remarkable properties, such as good biocompatibility, strong mechanical strength, and outstanding electrical conductivity, have dramatically shown excellent potential in various applications. Increasing surface area and porosity percentage, improvement of adsorption capacities, reduction of adsorption energy barrier, and also prevention of agglomeration of graphene layers are the main advantages of functionalized graphene nanocomposites. On the other hand, Cerium nanostructures with remarkable properties have received a great deal of attention in a wide range of fields; however, in some cases low conductivity limits their application in different applications. Therefore, the combination of cerium structures and graphene networks has been widely invesitaged to improve properties of the composite. In order to have a comprehensive information of these nanonetworks, this research reviews the recent developments in cerium functionalized graphene derivatives (graphene oxide (GO), reduced graphene oxide (RGO), and graphene quantum dot (GQD) and their industrial applications. The applications of functionalized graphene derivatives have also been successfully summarized. This systematic review study of graphene networks decorated with different structure of Cerium have potential to pave the way for scientific research not only in field of material science but also in fluorescent sensing, electrochemical sensing, supercapacitors, and catalyst as a new candidate.

Controlling the Interfacial Charge Polarization of MOF-Derived 0D-2D vdW Architectures as a Unique Strategy for Bifunctional Oxygen Electrocatalysis

The design of alternative earth-abundant van der Waals (vdW) nanoheterostructures for bifunctional oxygen evolution/reduction (OER/ORR) electrocatalysis is of paramount importance to fabricate energy-related devices. Herein, we report a simple metal-organic framework (MOF)-derived synthetic strategy to fabricate low-dimensional (LD) nanohybrids formed by zero-dimensional (0D) ZrO₂ nanoparticles (NPs) and heteroatom-doped two-dimensional (2D) carbon nanostructures. The 2D platforms controlled the electronic structures of interfacial Zr atoms, thus producing optimized electron polarization for boron and nitrogen-doped carbon (BCN)/ZrO₂ nanohybrids. X-ray photoelectron spectroscopy (XPS) and theoretical studies revealed the key role of the synergistic couple effect of boron (B) and nitrogen (N) in interfacial electronic polarization. The BCN/ZrO₂ nanohybrid showed excellent bifunctional electrocatalytic activity, delivering an overpotential (η₁₀) of 301 mV to reach a current density of 10 mA-cm^-2 for the OER process and a half-wave potential (E_1/2) of 0.85 V vs reversible hydrogen electrode (RHE) for the ORR process, which are comparable to the state-of-the-art LD nanohybrids. Furthermore, BCN/ZrO₂ also showed competitive performances for water-splitting and zinc-air battery devices. This work establishes a new route to fabricate highly efficient multifunctional electrocatalysts by tuning the electronic polarization properties of 0D-2D electrochemical interfaces.

Recent Advances in Faradic Electrochemical Deionization: System Architectures versus Electrode Materials

Capacitive deionization (CDI) is an energy-efficient desalination technique. However, the maximum desalination capacity of conventional carbon-based CDI systems is approximately 20 mg g^-1, which is too low for practical applications. Therefore, the focus of research on CDI has shifted to the development of faradic electrochemical deionization systems using electrodes based on faradic materials which have a significantly higher ion-storage capacity than carbon-based electrodes. In addition to the common symmetrical CDI system, there has also been extensive research on innovative systems to maximize the performance of faradic electrode materials. Research has focused primarily on faradic reactions and faradic electrode materials. However, the correlation between faradic electrode materials and the various electrochemical deionization system architectures, i.e., hybrid capacitive deionization, rocking-chair capacitive deionization, and dual-ion intercalation electrochemical desalination, remains relatively unexplored. This has inhibited the design of specific faradic electrode materials based on the characteristics of individual faradic electrochemical desalination systems. In this review, we have characterized faradic electrode materials based on both their material category and the electrochemical desalination system in which they were utilized. We expect that the detailed analysis of the properties, advantages, and challenges of the individual systems will establish a fundamental correlation between CDI systems and electrode materials that will facilitate future developments in this field.

Tailoring the defects of sub-100 nm multipodal titanium nitride/oxynitride nanotubes for efficient water splitting performance

Deciphering the photocatalytic-defect relationship of photoanodes can pave the way towards the rational design for high-performance solar energy conversion. Herein, we rationally designed uniform and aligned ultrathin sub-100 nm multipodal titanium nitride/oxynitride nanotubes (TiON _x NTs) (x = 2, 4, and 6 h) via the anodic oxidation of Ti-foil in a formamide-based electrolyte followed by annealing under ammonia gas for different durations. XPS, XPS imaging, Auger electron spectra, and positron annihilation spectroscopy disclosed that the high nitridation rate induced the generation of a mixture of Ti-nitride and oxynitride with various vacancy-type defects, including monovacancies, vacancy clusters, and a few voids inside TiO _x NTs. These defects decreased the bandgap energy to 2.4 eV, increased visible-light response, and enhanced the incident photon-to-current collection efficiency (IPCE) and the photocurrent density of TiON _x NTs by nearly 8 times compared with TiO₂NTs, besides a quick carrier diffusion at the nanotube/electrolyte interface. The water-splitting performance of sub-100 nm TiON₆NT multipodal nanotubes was superior to the long compacted TiON _x NTs with different lengths and TiO₂ nanoparticles. Thus, the optimization of the nitridation rate tailors the defect concentration, thereby achieving the highest solar conversion efficiency.

Tuning the Intermolecular Electron Transfer of Low-Dimensional and Metal-Free BCN/C60 Electrocatalysts via Interfacial Defects for Efficient Hydrogen and Oxygen Electrochemistry

The development of low-dimensional (LD) supramolecular materials with multifunctional electrocatalytic properties has sparked the attention of the catalysis community. Herein, we report the synthesis of a new class of 0D-2D heterostructures composed of boron carbon nitride nanosheets (BCN NSs) and fullerene molecules (C₆₀/F) that exhibit multifunctional electrocatalytic properties for the hydrogen evolution/oxidation reactions (HER/HOR) and the oxygen evolution/reduction reactions (OER/ORR). The electrocatalytic properties were studied with varying F:BCN weight ratios to optimize the intermolecular electron transfer (ET) from the BCN NSs to the electron-accepting C₆₀ molecules. The nanohybrid supramolecular material with 10 wt % F in BCN NSs (10% F/BCN) exhibited the largest Raman and C 1s binding energy shifts, which were associated with greater cooperativity interactions and enhanced ET processes at the F/BCN interface. This synergistic interfacial phenomenon resulted in highly active catalytic sites that markedly boosted electrocatalytic activity of the material. The 10% F/BCN showed the highest tetrafunctional catalytic performance, outperforming the OER catalytic activity of commercial RuO₂ catalysts with a η₁₀ of 390 mV and very competitive onset potential values of -0.042 and 0.92 V vs RHE for HER and ORR, respectively, and a current density value of 1.47 mA cm^-2 at 0.1 V vs RHE with an ultralow ΔG_H* value of -0.03 eV toward the HOR process. Additionally, the 10% F/BCN catalyst was also used as both cathode and anode in a water splitting device, delivering a cell potential of 1.61 V to reach a current density of 10 mA cm^-2.

Smart design of exquisite multidimensional multilayered sand-clock-like upconversion nanostructures with ultrabright luminescence as efficient luminescence probes for bioimaging application

A facile scalable approach is presented for the rational design of multidimensional, multilayered sand-clock-like UCNPs (denoted as UCCKs) bounded with high index facets, with a tunable Nd³⁺ content, and without a template or multiple complicated reaction steps. This was achieved using the seed-mediated growth and subsequent longitudinal direction epitaxial growth with the assistance of oleic acid and NH₄F. The as-formed UCCKs composed of an inner layer (NaYF₄:Yb,Er,Ca), an intermediate layer (NaYF₄:Yb,Ca), and an outer layer (NaNdF₄:Yb,Ca). The outer shell, enriched with Nd³⁺ sensitizer, augmented the near-infrared (NIR) photon absorption, whereas the intermediate shell, enriched with Yb³⁺, acted as a bridge for energy transfer from Nd³⁺ to Er³⁺ emitter in the inner core alongside with precluding any deleterious energy back-transfer from Er³⁺ or quenching effect from Nd³⁺. These unique structural and compositional properties of UCCKs endowed the UCL intensity of UCCKs by 22 and 10 times higher than that of hexagonal UCNP core (NaYF₄:Yb,Er,Ca) and hexagonal UCNP core-shell (NaYF₄:Yb,Er,Ca@NaYF₄:Yb,Ca), respectively. Intriguingly, the UCL intensity increased significantly with increasing the content of Nd³⁺ in the outer shell. The silica-coated UCCKs were used as excellent long-term luminescence probes for the in vitro bioimaging without any noteworthy cytotoxicity. The presented approach may pave the road for controlling the synthesis of multidimensional UCCKs for various applications. Graphical abstract We developed novel multidimensional multilayered sand-clock-like upconversion nanostructures composed of a spherical inner core (NaYF₄:Yb,Er,Ca), hexagonal intermediate shell (NaYF₄:Yb,Ca) and two up-down outer shell (NaNdF₄:Yb,Ca) with controllable Nd³⁺ as an efficient and safe probe for bioimaging applications without any quenching effect.

Unveiling One-Pot Template-Free Fabrication of Exquisite Multidimensional PtNi Multicube Nanoarchitectonics for the Efficient Electrochemical Oxidation of Ethanol and Methanol with a Great Tolerance for CO

Multidimensional bimetallic Pt-based nanoarchitectonics are highly promising in electrochemical energy conversion technologies because of their fancy structural merits and accessible active sites; however, hitherto their precise template-free fabrication remains a great challenge. We report a template-free solvothermal one-pot approach for the rational design of cocentric PtNi multicube nanoarchitectonics via adjusting the oleylamine/oleic acid ratio with curcumin. The obtained multidimensional PtNi multicubes comprise multiple small interlace-stacked nanocube subunits assembled in spatially porous branched nanoarchitectonics and bound by high-index facets. The synthetic mechanism is driven by spontaneous isolation among prompt nucleation and oriented attachment epitaxial growth. These inimitable architectural and compositional merits of PtNi multicubes endowed the ethanol oxidation mass and specific activity by 5.6 and 9.03 times than the Pt/C catalyst, respectively, along with the enhancement of methanol oxidation mass activity by 2.3 times. Moreover, PtNi multicubes showed superior durability and a higher tolerance for CO poisoning than the Pt/C catalyst. This work may pave the way for tailored preparation of Pt-based nanoarchitectonics for myriad catalytic reactions.

Data on the synthesis and characterizations of carboxylated carbon-based catalyst from eucalyptus as efficient and reusable catalysts for hydrolysis of eucalyptus

The presented article reports the preparation and characterization of heterogeneous carbon catalyst enriched with carboxylic group denoted as (ECS) from Eucalyptus as an efficient catalyst for the hydrolysis of woody Eucalyptus biomass. The fabrication process is based on the ball milling of Eucalyptus as a carbon source in the presence of dry ice as an oxidizing agent followed by acidification with the assistance of hydrochloric acid. The data are including the schematic for the full synthesis steps and characterization tools in addition to the thermogravimetric analysis and proton nuclear magnetic resonance analysis for the ECS catalyst. Meanwhile, the catalytic performance of ECS catalyst towards the hydrolysis of Eucalyptus was measured under different temperatures ranged from 160  to 200 °C. The ECS catalyst allowed the selective hydrolysis of Eucalyptus to glucose and xylose, as proved by high-performance liquid chromatography. The data herein are associated with the article entitled " Unveiling one-pot fabrication of scalable and reusable carboxylated heterogeneous carbon-based catalyst from Eucalyptus plant with the assistance of dry Ice for selective hydrolysis of Eucalyptus Biomass'' [1].

Unveiling Fabrication and Environmental Remediation of MXene-Based Nanoarchitectures in Toxic Metals Removal from Wastewater: Strategy and Mechanism

Efficient approaches for toxic metal removal from wastewater have had transformative impacts to mitigating freshwater scarcity. Adsorption is among the most promising purification techniques due to its simplicity, low cost, and high removal efficiency at ambient conditions. MXene-based nanoarchitectures emerged as promising adsorbents in a plethora of toxic metal removal applications. This was due to the unique hydrophilicity, high surface area, activated metallic hydroxide sites, electron-richness, and massive adsorption capacity of MXene. Given the continual progress in the rational design of MXene nanostructures for water treatment, timely updates on this field are required that deeply emphasize toxic metal removal, including fabrication routes and characterization strategies of the merits, advantages, and limitations of MXenes for the adsorption of toxic metals (i.e., Pb, Cu, Zn, and Cr). This is in addition to the fundamentals and the adsorption mechanism tailored by the shape and composition of MXene based on some representative paradigms. Finally, the limitations of MXenes and their potential future research perspectives for wastewater treatment are also discussed. This review may trigger scientists to develop novel MXene-based nanoarchitectures with well-defined shapes, compositions, and physiochemical merits for efficient, practical removal of toxic metals from wastewater.

Tailored fabrication of iridium nanoparticle-sensitized titanium oxynitride nanotubes for solar-driven water splitting: experimental insights on the photocatalytic–activity–defects relationship

Uniform and vertically aligned nanotube arrays of titanium oxynitride functionalized with iridium nanoparticles (Ir/TiON-NTs) were fabricated for the solar driven-water splitting.

Data on structural and composition-related merits of gC3N4 nanofibres doped and undoped with Au/Pd at the atomic level for efficient catalytic CO oxidation

Precise design of graphitic carbon nitride (gC₃N₄) nanostructures is of grand importance in different catalytic applications. This article emphasizes additional data on the fabrication of metal-free gC₃N₄ nanofibres (gC₃N₄NFs) and its associated structural and composition analysis compared with Au/Pd co-doped gC₃N₄ nanofibres (Au/Pd/gC₃N₄NFs). The data is including the typical fabrication process of metal-free gC₃N₄ nanofibers and its SEM, TEM, and element mapping analysis beside Raman, and FTIR spectra relative to Au/Pd/gC₃N₄NFs. We also investigated the catalytic CO oxidation durability testes on Au/Pd/gC₃N₄NFs compared to Pd/gC₃N₄NFs and Au/gC₃N₄NFs. The presented data are associated with the research article entitled “Rational synthesis of one-dimensional carbon nitride-based nanofibers atomically doped with Au/Pd for efficient carbon monoxide oxidation.” [1].

Novel Enzyme-Free Multifunctional Bentonite/Polypyrrole/Silver Nanocomposite Sensor for Hydrogen Peroxide Detection over a Wide pH Range

Precise designs of low-cost and efficient catalysts for the detection of hydrogen peroxide (H₂O₂) over wide ranges of pH are important in various environmental applications. Herein, a versatile and ecofriendly approach is presented for the rational design of ternary bentonite-silylpropyl-polypyrrole/silver nanoarchitectures (denoted as BP-PS-PPy/Ag) via the in-situ photo polymerization of pyrrole with salinized bentonite (BP-PS) in the presence of silver nitrate. The Pyrrolyl-functionalized silane (PS) is used as a coupling agent for tailoring the formation of highly exfoliated BP-PS-PPy sheet-like nanostructures ornamented with monodispersed Ag nanoparticles (NPs). Taking advantage of the combination between the unique physicochemical properties of BP-PS-PPy and the outstanding catalytic merits of Ag nanoparticles (NPs), the as-synthesized BP-PS-PPy/Ag shows a superior electrocatalytic reduction and high-detection activity towards H₂O₂ under different pH conditions (from 3 to 10). Intriguingly, the UV-light irradiation significantly enhances the electroreduction activity of H₂O₂ substantially, compared with the dark conditions, due to the high photoelectric response properties of Ag NPs. Moreover, BP-PS-PPy/Ag achived a quick current response with a detection limit at 1 μM within only 1 s. Our present approach is green, facile, scalable and renewable.

Unraveling template-free fabrication of carbon nitride nanorods codoped with Pt and Pd for efficient electrochemical and photoelectrochemical carbon monoxide oxidation at room temperature

The tailored synthesis of carbon nitrides (CNs) is of particular interest in multidisciplinary catalytic applications. However, their fabrication in the form of one-dimensional (1D) nanorods for electrocatalytic carbon monoxide (CO) oxidation is not hitherto reported. Herein, a facile roadmap is presented for the rational design of Pt- and Pd-codoped CN (PtPd/CNs) nanorods via protonation of melamine in an ethylene glycol solution containing Pt and Pd precursors using NaNO3 and HCl and subsequent annealing. The protonation induces the polymerization of melamine to melon nanosheets that consequently roll up to CN nanorods. This tailored the prompt high mass production of uniform 1D CN nanorods (94 ± 2 nm) with a high surface area (155.2 m2 g-1) and they were atomically codoped with Pt and Pd (1.5 wt%) without a template and/or multiple complicated steps. The electrocatalytic CO oxidation activity of PtPd/CNs is 2.01 and 23.41 times greater than that of the commercial Pt/C catalyst and metal-free CNs, respectively, at room temperature. Meanwhile, the UV-vis light irradiation enhanced the CO oxidation activity of PtPd/CNs nanorods by 1.48 fold compared to that in the dark, emanated from the coupling between the drastic inbuilt catalytic merits of PtPd and the inimitable physicochemical properties of CNs. The presented study may pave the way for using CN-based materials in gas conversion reactions.

Rational synthesis of three-dimensional core-double shell upconversion nanodendrites with ultrabright luminescence for bioimaging application

Herein, we rationally fabricated three-dimensional upconversion core–double shell nanodendrites as efficient and safe luminescent probes for in vitro and in vivo bioimaging.

Engineering the morphology of rare-earth doped NaYF₄-based upconversion nanoparticles (UCNPs) can effectively tune their upconversion luminescence emission (UCLE) properties. Herein, we rationally synthesized a new class of three-dimensional upconversion core–double-shell nanodendrites (UCNDs) including an active core (NaYF₄:Yb,Er,Ca) capped by a transition layer (NaYF₄:Yb,Ca) and an active outer shell (NaNdF₄:Yb,Ca). The high concentration of the Nd³⁺ sensitizer in the outer dendritic shell enhances the luminescence intensity, while the transition layer enriched with Yb³⁺ acts as an efficient energy migration network between the outer shell and inner core along with preventing the undesired quenching effects resulting from Nd³⁺. These unique structural and compositional merits enhanced the UCLE of UCNDs by 5 and 15 times relative to NaYF₄:Yb,Er,Ca@NaYF₄:Yb,Ca truncated core–shell UCNPs and NaYF₄:Yb,Er,Ca spherical core UCNPs, respectively, under excitation at 980 nm. The SiO₂–COOH layer coated UCNDs (UCND@SiO₂–COOH) were successfully used as efficient long-term luminescent probes for in vitro and in vivo bioimaging without any significant toxicity. The uptake and retention of UCND@SiO₂–COOH were mostly found in the liver and spleen. This study may open the way towards the preparation of three-dimensional UCND nanostructures for biomedical applications.

Rational Synthesis of Porous Graphitic-like Carbon Nitride Nanotubes Codoped with Au and Pd as an Efficient Catalyst for Carbon Monoxide Oxidation

The precise fabrication of efficient catalysts for CO oxidation is of particular interest in a wide range of industrial and environmental applications. Herein, a scalable method is presented for the controlled synthesis of graphitic-like porous carbon nitride nanotubes (gC₃N₄NTs) codoped with Au and Pd (Au/Pd/gC₃N₄NTs) as efficient catalysts for carbon monoxide (CO) conversion. This includes the activation of melamine with nitric acid in the presence of ethylene glycol and metal precursors followed by consecutive polymerization and carbonization. This drives the formation of porous one-dimensional gC₃N₄NT with an outstanding surface area of (320.6 m² g^-1) and an atomic-level distribution of Au and Pd. Intriguingly, the CO conversion efficiency of Au/Pd/gC₃N₄NTs was substantially greater than that for gC₃N₄NTs. The approach thus presented may provide new avenues for the utilization of gC₃N₄ doped with multiple metal-based catalysts for CO conversion reactions which had been rarely reported before.

Accuracy of patient-specific guided implantation of the glenoid component in reversed shoulder arthroplasty

BACKGROUND

The aim of this study was to assess the accuracy of patient-specific guided glenoid component implantation in reverse shoulder arthroplasty.

MATERIALS AND METHODS

32 reverse shoulder arthroplasties were done using preoperative 3D planning and 4 patient-specific guides to prepare the glenoid and position the glenoid component. Baseplate version, inclination and entry point as well as angulation of the screws were compared to the preoperative plan measured on CT by independent observers.

RESULTS

The mean deviation in baseplate version from the preoperative plan was 4.4°+3.1° (range, 0.3°-13.7°), in baseplate inclination 5.0°+4.2° (range, 0.1° to 14.5°) and in baseplate entry point 2.4mm+1.4mm (range, 0.4° to 6.3°). The average screw superior-inferior angulation deviation for the superior screw was 2.8°+2.6° (range, 0.0°-10.1°) and 2.8+2.6° in the antero-posterior plane (range, 0.1°-11.6°). For the inferior screw the superior-inferior angle deviation was 5.3°+3.8° (range, 0.1°-15.2°); the antero-posterior angle deviation was 4.1°+3.1° (range, 0.0°-9.8°).

CONCLUSIONS

Patient-specific instrumentation (PSI) for the glenoid component in reverse shoulder arthroplasty allows the shoulder surgeon to accurately execute the preoperative 3D plan.

LEVEL OF EVIDENCE

Level 3.

Controlled design of PtPd nanodendrite ornamented niobium oxynitride nanosheets for solar-driven water splitting

A facile road-map is developed for one-pot synthesis of PtPd nanodendrite ornamented niobium oxynitride nanosheets for efficient solar-driven water splitting.

One-pot synthesis of bimetallic PdCu nanoframes as an efficient catalyst for the methanol oxidation reaction

A one-pot method is developed for the synthesis of PdCu nanoframes which are an active catalyst for the methanol oxidation reaction.

Rational one-step synthesis of porous PtPdRu nanodendrites for ethanol oxidation reaction with a superior tolerance for CO-poisoning

Precise fabrication of porous ternary Pt-based nanodendrites is very important for electrochemical energy conversion owing to high surface area and great molecular accessibility of these nanodendrites. Herein, PtPdRu porous nanodendrites (PNDs) were prepared via a facile one-step ultrasonic irradiation approach at room temperature. Intriguingly, the ultrasonic irradiation drove the formation of PtPdRu PNDs with spatially interconnected porous structures, whereas magnetic stirring produced PtPdRu nanoflowers (NFs) with less porosity. The formation mechanism was ascribed to the acoustic cavitation effect and fast-reduction kinetics under sonication. The as-made PtPdRu PNDs displayed a superior catalytic performance towards ethanol oxidation reaction with a high tolerance for CO-poisoning as compared to PtPdRu NFs, PtPd NDs, and commercial Pt/C catalyst.

One-pot synthesis of PtRu nanodendrites as efficient catalysts for methanol oxidation reaction

Bimetallic Pt-based nanodendrites are of particular interest in various catalytic applications due to their high surface areas and low densities. Herein, we provide a facile method for one-pot synthesis of PtRu nanodendrites via the co-reduction of Pt and Ru precursors in oleylamine by H₂. The as-fabricated PtRu nanodendrites exhibit superior catalytic activity and durability compared with PtRu nanocrystals (NCs), synthesized under the same reaction conditions, and the commercial Pt/C catalyst towards the methanol oxidation reaction (MOR).

Rational design of porous binary Pt-based nanodendrites as efficient catalysts for direct glucose fuel cells over a wide pH range

Porous binary PtPd, AuPt, PtCu, and PtNi nanodendrites prepared by a facile one-step reduction under ultrasonic irradiation at room temperature, exhibited a substantial catalytic activity towards glucose oxidation reaction at different pH values relative to a commercial Pt/C catalyst.