Graphdiyne: Recent Achievements in Photo- and Electrochemical Conversion

Porous Silicon-Supported Catalytic Materials for Energy Conversion and Storage

Porous silicon (Si) has a tetrahedral structure similar to that of sp3-hybridized carbon atoms in a typical diamond structure, which affords it unique chemical and physical properties including an adjustable intrinsic bandgap, a high-speed carrier transfer efficiency. It has shown great potential in photocatalysis, rechargeable batteries, solar cells, detectors, and electrocatalysis. This review introduces various porous Si-supported electrocatalysts and analyzes the reasons why porous Si is used as a new carrier/active sites from the perspectives of its molecular structure, electronic properties, synthesis methods, etc. The electrochemical applications of porous Si-based electrocatalysts in energy conversion reactions such as hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, and total water decomposition together with lithium-ion battery and supercapacitor in energy storage are summarized. The challenges and future research directions for porous Si are also discussed. This review aims to deepen the understanding of porous Si and promote the development and applications of this new type of Si material.

Transition metals anchored on nitrogen-doped graphdiyne for an efficient oxygen reduction reaction: a DFT study

The search for highly active and low-cost single-atom catalysts for the oxygen reduction reaction (ORR) is essential for the widespread application of proton exchange membrane fuel cells. Transition metals anchored on nitrogen-doped graphdiyne (GDY) have attracted considerable interest as potentially excellent catalysts for the ORR. However, the relationship between the active site and nitrogen-doped GDY remains unclear. In this work, we conducted a systematic investigation of sp-hybridized N atoms anchoring single transition metal atoms of 3d and 4d on GDY (TMC2N2) as electrocatalysts for the ORR. Firstly, 18 kinds of TMC2N2 were determined to have good thermodynamic stability. Due to the extremely strong adsorption of *OH, TMC2N2 exhibits inferior ORR performance compared to traditional Pt(111). Considering that *OH adsorption hinders the catalytic activity of TMC2N2, we modified the OH ligand of TMC2N2 to develop the high-valent metal complex (TMC2N2-OH) aiming to enhance the electrocatalytic activity. The adsorption of intermediates on most TMC2N2-OH is weakened after the modification of the OH ligand, especially for the adsorption of *OH. Thus, by comparing the ORR overpotential of catalysts before and after ligand modification, we find that the catalytic activity of different TMC2N2-OHs improves to various degrees. MnC2N2-OH, TMC2N2-OH, and TcC2N2-OH exhibit relatively high ORR catalytic activity, with overpotentials of 0.93 V, 1.19 V, and 0.92 V, respectively. Furthermore, we investigated the cause of improved catalytic activity of TMC2N2-OH and found that the modified coordination environment of the catalyst led to adjusted adsorption of ORR intermediates. In summary, our work sheds light on the relationship between nitrogen-doped GDY and transition metal sites, thus contributing to the development of more efficient catalysts.

Excellent Anode Performance of N-, P-, and As-Doped Graphdiynes for Lithium-Ion Batteries

Recently, graphdiyne (GDY) as a two-dimensional planar carbon allotrope has received significant research attention in the fields of rechargeable batteries, catalysis, biomedicine, and so forth. However, the theoretical capacity of a perfect GDY anode is only 744 mA h/g in the configuration of LiC3, encouraging further efforts to increase the capacity. In this study, we explore the anode performance of N-, P-, and As-doped GDYs by using first-principles calculations. Ab initio molecular dynamics simulations show that the doped GDYs can remain stable at 1000 K, indicating good thermal stability. With the loss of part acetylenic linkages, the rhomboid-like pores produce more Li sites, and the theoretical capacities reach 2209, 2031, and 1681 mA h/g for the N-, P-, and As-doped GDYs, respectively. In addition, the transition-state calculations indicate that the Li diffusion barriers of the three doped GDYs are similar to the perfect GDY. This study demonstrates that doping is an effective strategy to improve the anode performance of GDY.

Construction of Reinforced Self-Cleaning and Efficient Photothermal PDMS@GDY@Cu Sponges toward Anticorrosion and Antibacterial Applications

Copper (Cu)-based materials are widely used in many fields from industry to life, including marine, medical apparatus and instruments, and microelectronic devices owing to their superior thermal, electrical, and mechanical properties. However, the interaction of copper with aggressive and fouling liquids under normal circumstances easily brings about severe bacterial accumulation, resulting in undesirable functionality degeneration and bacterial infections. In this contribution, we reported a novel copper-based sponge, polydimethylsiloxane (PDMS)@graphdiyne (GDY)@Cu, constructed by in situ synthesis of GDY on a commercial Cu sponge, followed by the modification of PDMS. The as-fabricated PDMS@GDY@Cu sponge not only possesses excellent self-cleaning activity against the pollution of daily drinks and dirt due to an improved static contact angle (~136°), but also display a remarkably enhanced anticorrosion performance, attributed to intimate coverage of chemically stable GDY and PDMS on the Cu sponge. Based on high photothermal effect of GDY, the PDMS@GDY@Cu sponge also displays significantly improved antibacterial activities under irradiation. In addition, due to excellent chemical stability of PDMS and GDY, self-cleaning behavior and photothermal-assisted antibacterial performance are well maintained after long-term attack of bacteria. These results demonstrate that GDY-based functional coatings hold great promises in the protection of copper devices under harsh conditions.

Boosting charge separation in graphdiyne quantum dots/hollow tubular carbon nitride heterojunction for water pollutant degradation

Non-desirable solar energy absorption and poor charge transfer efficiency are two problems that limit the peroxymonosulfate (PMS) photocatalytic techniques. Herein, a metal-free boron-doped graphdiyne quantum dot (BGDs) modified hollow tubular g-C₃N₄ photocatalyst (BGD/TCN) was synthesized to activate PMS and achieved effective space separation of carriers for degradation of bisphenol A. With 0.5 mM PMS, the degradation rate of bisphenol A (20 ppm) was 0.0634 min^-1, 3.7-fold higher than that of TCN itself. The roles of BGDs in the distribution of electrons and photocatalytic property were well identified by experiments and density functional theory (DFT) calculations. The possible degradation intermediate products of bisphenol A were monitored by mass spectrometer and demonstrated to be nontoxic using ecological structure activity relationship modeling (ECOSAR). Finally, this newly-designed material was successfully applied in actual water bodies, which further renders its promising prospect for actual water remediation.

Single-metal atom sandwiched by graphdiyne and BN-doped graphdiyne sheets as an electrocatalyst for nitrogen reduction: a first-principles study

The exploration of efficient single-atom catalysts provides a prospective pattern for the sustainable development of electrocatalytic nitrogen fixation. We systematically researched the nitrogen reduction properties of catalysts with a single transition metal (TM) atom sandwiched between BN-doped graphdiyne and graphdiyne (labeled BN-TM-G) by first-principles calculations. The TM atom in the novel sandwich structure provides electrons to the adjacent B atom, which acts as the active site, thus driving the fixation and reduction of N₂. In the BN-TM-G system, the NRR catalytic activity is bound up with the positive charge polarization level of the TM atom. Among them, BN-Sc-G, BN-Ti-G, BN-V-G, and BN-Cr-G systems showed higher catalytic ability, and the competitive HER was inhibited. In particular, the lowest limiting potential of BN-Cr-G is -0.63 V is promising for the NRR catalyst.

A Deprotection-free Method for High-yield Synthesis of Graphdiyne Powder with In Situ Formed CuO Nanoparticles

With a direct band gap, superior charge carrier mobility, and uniformly distributed pores, graphdiyne (GDY) has stimulated tremendous interest from the scientific community. However, its broad application is greatly limited by the complicated multistep synthesis process including complex deprotection of hexakis-[(trimethylsilyl)ethynyl]benzene (HEB-TMS) and peeling of GDY from the substrates. Here, we describe a deprotection-free strategy to prepare GDY powder by directly using HEB-TMS as the monomer. When CuCl was used as the catalysts in DMF solvent, the yield of GDY powder reached ≈100 %. More interestingly, uniformly dispersed CuO nanoparticles with an average diameter of ≈2.9 nm were in situ formed on GDY after the reaction. The prepared CuO/GDY was demonstrated an excellent co-catalyst for photocatalytic hydrogen evolution, comparable to the state-of-art Pt co-catalyst. The deprotection-free approach will widen the use of GDY and facilitate its scaling up to industrial level.

Conversion of Interfacial Chemical Bonds for Inducing Efficient Photoelectrocatalytic Water Splitting

Sp-C-hybridized alkyne bonds present the natural advantages of interacting with metal atoms and have the ability to generate a large number of new catalytic active sites on the surface and the interfaces, thus greatly promoting the efficient progress of various light/electrochemical reactions. In this work, we have successfully fabricated a novel type of interfacial structure containing sp-C-Mo/O bonds and mixed Mo valence states with outstanding catalytic activity and stability for photoelectrocatalytic (PEC) overall water splitting in a wide pH range (0-14), due to the presence of sp-carbon-rich graphdiyne. For example, in alkaline conditions (pH = 14), the overpotentials of oxygen and hydrogen evolution reactions at 10 mA cm-2 are 165 and 8 mV. When being used as an electrolyzer, the cell voltage of this catalyst is only 1.40 V to achieve 10 mA cm-2. The high PEC activity of graphdiyne@molybdenum oxide originates from the conversion of chemical bonds at the sp-C hybrid interface and the coexistence of multivalent states of molybdenum, triggering a large number of catalytic active sites, greatly promoting charge transfer and lowering water dissociation energy.

Transition Metal-Modified Co4 Clusters Supported on Graphdiyne as an Effective Nitrogen Reduction Reaction Electrocatalyst

Conversion of N₂ into NH₃ through the electrochemical nitrogen reduction reaction (NRR) under ambient conditions represents a novel green ammonia synthesis method. The main obstacle for NRR is lack of efficient, stable, and cost-effective catalysts. In this work, by using density functional theory calculations, 16 transition metal-modified Co₄ clusters supported on graphdiyne (GDY) as potential NRR catalysts were systematically screened. Through the examinations of stability, N₂ activation, selectivity, and activity, Ti-, V-, Cr-, Mn-, and Zr-Co₃@GDY were identified as the promising candidates toward NRR. Further explorations on the NRR mechanisms and the Pourbaix diagrams suggest that Ti-Co₃@GDY was the most promising candidate catalyst, as it has the lowest limiting potential and high stability under the working conditions. The high activities originate from the synergy effect, where the Co₃ cluster acts as the electron donor and the heteroatom serves as the single active site throughout the NRR process. Our results offer a new perspective for advancing sustainable NH₃ production.

Nanoengineering of Advanced Carbon Materials for Sodium-Ion Batteries

Recent research shows that the continuing importance of carbon anode materials plays an important role in the development of sodium-ion batteries. Nevertheless, the practical deployment of sodium-ion batteries still faces many challenges such as mediocre sodium storage capability and short cycle life. Therefore, it is imperative to explore improvement methods to boost their competitiveness. Herein, various nanoengineering strategies, including nanostructure design, defect and heteroatom doping, and nanocomposite optimization, are proposed as reliable and effective approaches to improve electrochemical performances and structural stability of carbon-based anode materials for sodium-ion batteries (SIBs). The feasibility of nanoengineering is highlighted as a promising approach to develop next-generation carbon materials for sodium-ion batteries.

Post-modified Strategies of Graphdiyne for Electrochemical Applications

The new carbon material graphdiyne (GDY) has been verified to have a great application prospect in electrochemical field. In order to study its properties and expand its scope of application, various experiments including structural control tests are imposed on GDY. Among them, as one of the most commonly used methods to modify the structure, heteroatom doping is favored for its advantages in synthesis methods and the control of mechanical, electrical and even magnetic properties of carbon materials. According to the published studies, the top-down methods of doping heteroatoms for GDY only need cheap raw materials, simple synthetic route and strong controllability, which is conducive to rapid performance breakthroughs in electrochemical applications. This review selects the typical cases in the development of that post-modification method from the application of GDY in the electrochemical field. Here, based on the existed reports, the commonly used non-metal elements (such as nitrogen, sulfur) and metal elements (such as iron) have been introduced to post-modify GDY. Then, a detailed analysis is made for corresponding electrochemical applications, such as energy storage and electrocatalysis. Finally, the challenges and prospects of post-modified GDY in synthesis and electrochemical applications are proposed. This review provides us a useful guidance for the development of high-quality GDY suitable for electrochemical applications.

Two-Dimensional Nanosheets-Based Soft Electro-Chemo-Mechanical Actuators: Recent Advances in Design, Construction, and Applications

Soft electro-chemo-mechanical actuators have received enormous interest in biomimetic technologies, wearable electronics, and microelectromechanical systems due to their low voltage-driven large deformation, fast response, high strain, and working durability. Two-dimensional (2D) nanosheets, which can highly promote ion-induced micromotion to macrodeformation, have outstandingly been used as prime actuator electrodes because of their ordered microstructures, tunable interlayer spaces, controllable electrochemical activities, and excellent electrical and mechanical properties. Here, this review primarily focuses on the recent advances in key 2D electro-chemo-mechanical actuator electrodes, including graphene, MXenes, graphitic carbon nitride, molybdenum disulfide, black phosphorus, and graphdiyne. Various synthetic strategies of electrode design, such as microstructural architecture, active-site regulation, and channel construction, for achieving high ionic kinetic transport, charge storage, and electrochemical-mechanical performances are discussed. The advanced structures with diverse building principles that provide ordered and active ionic pathways for high actuation speed and strain are emphasized. Furthermore, the innovative applications of electro-chemo-mechanical actuators toward biomimetic robots and smart devices are highlighted. Finally, the current challenges and future perspectives are also proposed. The aim of this review is to provide the guiding significance for scientific researchers and industrial engineers to design higher performance next-generation electro-chemo-mechanical actuators.

A phase-dependent photoluminescent discotic liquid crystal bearing a graphdiyne substructure

In recent years, graphdiyne and its derivatives with fascinating electro-optic properties have attracted tremendous scientific attention. Here we design and synthesize a graphdiyne-derived discotic liquid crystal material by decorating six wedge-shaped 3,4,5-tris(dodecyloxy)benzoate groups on the fundamental structural unit of graphdiyne, the dehydrotribenzo[18]annulene core. This graphdiyne-derived liquid crystal material exhibits a cubic phase and a hexagonal columnar phase at varied temperatures. Most interestingly, this molecule displays a tunable phase-dependent photoluminescence behavior. Under the irradiation of 365 nm wavelength ultraviolet light, the luminescent material emits pale blue, green and azure light in the cubic, hexagonal columnar and isotropic phases respectively. This graphdiyne-derived discotic liquid crystal with excellent optical characteristics might have application potentials in organic optoelectronic functional materials and devices.

Journey from Small-Molecule Diyne Structures to 2D Graphdiyne: Synthetic Strategies

Graphdiyne (GDY) exhibits unique characteristics of a highly conjugated π system, evenly distributed nanopores, and a direct band gap. This has encouraged multidisciplinary research groups to investigate its application in energy conversion and storage, catalysts, electronic devices, sensing, and separation. Herein, the achievements of synthetic strategies for preparing small-molecule diyne structures (GDY substructure), 1D nanoribbons, and 2D GDY are presented. These studies may help future investigations into the basic structure-related properties of GDY and synthetic methodology for the future developments of GDY-related 2D carbon materials.

Carbon-Based Nanocages: A New Platform for Advanced Energy Storage and Conversion

Energy storage and conversion play a crucial role in modern energy systems, and the exploration of advanced electrode materials is vital but challenging. Carbon-based nanocages consisting of sp² carbon shells feature a hollow interior cavity with sub-nanometer microchannels across the shells, high specific surface area with a defective outer surface, and tunable electronic structure, much different from the intensively studied nanocarbons such as carbon nanotubes and graphene. These structural and morphological characteristics make carbon-based nanocages a new platform for advanced energy storage and conversion. Up-to-date synthetic strategies of carbon-based nanocages, the utilization of their unique porous structure and morphology for the construction of composites with foreign active species, and their significant applications to the advanced energy storage and conversion are reviewed. Structure-performance correlations are discussed in depth to highlight the contribution of carbon-based nanocages. The research challenges and trends are also envisaged for deepening and extending the study and application of this multifunctional material.

Hydrophilic Conjugated Materials for Photocatalytic Hydrogen Evolution

Photocatalytic hydrogen evolution is viewed as a promising green strategy to utilize the inexhaustible solar energy and provide clean hydrogen fuels with zero-emission characteristic. The nature of semiconductor-based photocatalysts is the key point to achieve efficient photocatalytic hydrogen evolution. Conjugated materials have been recently emerging as a novel class of photocatalysts for hydrogen evolution and photocatalytic reactions due to their electronic properties can be well controlled via tailor-made chemical structures. Hydrophilic conjugated materials, a subgroup of conjugated materials, possess multiple advantages for photocatalytic applications, thus spurring remarkable progress on both material realm and photocatalytic applications. This minireview aims to provide a brief review of the recent developments of hydrophilic conjugated polymers/small molecules for photocatalytic applications, and special concern on the rational molecular design and their impact on photocatalytic performance will be reviewed. Perspectives on the hydrophilic conjugated materials and challenges to their applications in the photocatalytic field are also presented.

Metal-Tuned Acetylene Linkages in Hydrogen Substituted Graphdiyne Boosting the Electrochemical Oxygen Reduction

Different from graphene with the highly stable sp² -hybridized carbon atoms, which shows poor controllability for constructing strong interactions between graphene and guest metal, graphdiyne has a great potential to be engineered because its high-reactive acetylene linkages can effectively chelate metal atoms. Herein, a hydrogen-substituted graphdiyne (HsGDY) supported metal catalyst system through in situ growth of Cu₃ Pd nanoalloys on HsGDY surface is developed. Benefiting from the strong metal-chelating ability of acetylenic linkages, Cu₃ Pd nanoalloys are intimately anchored on HsGDY surface that accordingly creates a strong interaction. The optimal HsGDY-supported Cu₃ Pd catalyst (HsGDY/Cu₃ Pd-750) exhibits outstanding electrocatalytic activity for the oxygen reduction reaction (ORR) with an admirable half-wave potential (0.870 V), an impressive kinetic current density at 0.75 V (57.7 mA cm^-2 ) and long-term stability, far outperforming those of the state-of-the-art Pt/C catalyst (0.859 V and 15.8 mA cm^-2 ). This excellent performance is further highlighted by the Zn-air battery using HsGDY/Cu₃ Pd-750 as cathode. Density function theory calculations show that such electrocatalytic performance is attributed to the strong interaction between Cu₃ Pd and CC bonds of HsGDY, which causes the asymmetric electron distribution on two carbon atoms of CC bond and the strong charge transfer to weaken the shoulder-to-shoulder π conjugation, eventually facilitating the ORR process.

Adsorption, diffusion and aggregation of Ir atoms on graphdiyne: a first-principles investigation

Shifting the atomic diffusion thermodynamics, e.g. with involvement reactants, etc., would initiate the thermodynamically favorable aggregation of Ir atoms into clusters on graphdiyne.

Construction of a sp3 /sp2 Carbon Interface in 3D N-Doped Nanocarbons for the Oxygen Reduction Reaction

The development of highly efficient metal-free carbon electrocatalysts for the oxygen reduction reaction (ORR) is one very promising strategy for the exploitation and commercialization of renewable and clean energy, but this still remains a significant challenge. Herein, we demonstrate a facile approach to prepare three-dimensional (3D) N-doped carbon with a sp³ /sp² carbon interface derived from ionic liquids via a simple pyrolysis process. The tunable hybrid sp³ and sp² carbon composition and pore structures stem from the transformation of ionic liquids to polymerized organics and introduction of a Co metal salt. Through tuning both composition and pores, the 3D N-doped nanocarbon with a high sp³ /sp² carbon ratio on the surface exhibits a superior electrocatalytic performance for the ORR compared to that of the commercial Pt/C in Zn-air batteries. Density functional theory calculations suggest that the improved ORR performance can be ascribed to the existence of N dopants at the sp³ /sp² carbon interface, which can lower the theoretical overpotential of the ORR.

Interface Electronic Coupling in Hierarchical FeLDH(FeCo)/Co(OH)2 Arrays for Efficient Electrocatalytic Oxygen Evolution

The oxygen evolution reaction (OER) with sluggish kinetics is the key half-cell reaction for several sustainable energy systems, such as electrochemical water splitting, fuel cells, and rechargeable metal-air batteries. Two-dimensional transition-metal hydroxides have good prospects for the OER. Herein, 2D hierarchical FeLDH(FeCo)/Co(OH)₂ (LDH=layered double hydroxide) arrays were fabricated by growing 2D-ZIF-67 (ZIF=zeolitic imidazolate framework) on carbon cloth, transformation of 2D-ZIF-67 into Co(OH)₂ , and electrodeposition of FeLDH(FeCo) on Co(OH)₂ at ambient temperature. The optimized hierarchical catalyst exhibits high OER activity that requires a small overpotential of only 242 mV to drive 10 mA cm^-2 (279 mV for 100 mA cm^-2 ) and prolonged durability for 100 h at 20 mA cm^-2 in 1 m KOH. The FeLDH(FeCo)/Co(OH)₂ interfaces are observed to be the electrocatalytically active centers for the OER. The interfaces contribute to accelerating the OER kinetics owing to fast transfer of intermediate oxygen species. Furthermore, the FeCo alloy promotes electron transfer among the newly formed interfaces related to CoOOH in the OER process, which leads to improved durability. This work gives insight into the design and synthesis of hierarchical bimetallic hydroxide arrays with high OER activity and durability, as well as understanding of the origin of the OER promotion by metals and metal hydroxides.

Fluorographdiyne: A Metal-Free Catalyst for Applications in Water Reduction and Oxidation

A highly efficient bifunctional metal-free catalyst was prepared by growth of three-dimensional porous fluorographdiyne networks on carbon cloth (p-FGDY/CC). Our experiments and density functional theory (DFT) calculations show the 3D p-FGDY/CC network is highly active and it is a high potential metal-free catalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), as well as overall water splitting (OWS) under both acidic and alkaline conditions. The experimental and theoretical results show very good consistency; for example, in the HER process, p-FGDY/CC exhibits small overpotentials of 82 and 92 mV to achieve 10 mA cm^-2 under alkaline and acidic conditions, respectively. This ensures an even higher selectivity for the adsorption/desorption of various O/H intermediate species. The essential key promotion accomplishes a bifunctional H₂ O redox performance application under pH-universal electrochemical conditions.

Design and synthesis of CoIIHMTAA-14/16 macrocycles and their nano-composites for oxygen reduction electrocatalysis

The major concerns in the design of macrocycle based-ORR catalysts are: (i) understanding the macrocyclic, π-conjugation, central metal and substituent effects on ORR electrocatalysis; and (ii) the use of macrocycles on the electrode surface for the retention of ORR activity because of their poor stability. In this work, we demonstrated the aromaticity/π-electron conjugation effect on ORR activity by using the same macrocycles [HMTAA-14 and 16 (hexamethyltetraaza [14] and [16] annulenes)] with a difference in their macrocyclic cavity/π-electron conjugation. The macrocycles CoIIHMTAA-14 and CoIIHMTAA-16 and their nanocomposites with highly conductive carbon black were prepared by a microwave-assisted method and characterized by using multiple spectroscopy techniques. Comparative redox and oxygen reduction activity studies of CoIIHMTAA-14 and CoIIHMTAA-16 were undertaken by using cyclic voltammetry and linear sweep voltammetry in an alkaline medium. The composite CoIIHMTAA-16@C showed good ORR activity compared to CoIIHMTAA-14@C in O2-saturated KOH electrolyte. Since the CoIIHMTAA-14 and CoIIHMTAA-16 systems have a similar central atom and substituents, the shift of the ORR peak position in the +ive potential region for HMTAA-16 can be attributed to the difference in the size of the macrocyclic cavity (macrocyclic effect) and the extra stability of HMTAA-16 annulene due to its aromaticity.

Magnetically Hollow Pt Nanocages with Ultrathin Walls as a Highly Integrated Nanoreactor for Catalytic Transfer Hydrogenation Reaction

Fabricating efficient and stable nanocatalysts for chemoselective hydrogenation of nitroaromatics is highly desirable because the amines hold tremendous promise for the synthesis of nitrogen containing chemicals. Here, a highly reactive and stable porous carbon nitride encapsulated magnetically hollow platinum nanocage is developed with subnanometer thick walls (Fe3O4@snPt@PCN) for this transformation. This well-controlled nanoreactor is prepared via the following procedures: the preparation of core template, the deposition of platinum nanocage with subnanometer thick walls, oxidative etching, and calcination. This highly integrated catalyst demonstrates excellent performance for the catalytic transfer hydrogenation of various nitroaromatics and the reaction can reach >99% conversion and >99% selectivity. With the ultrathin wall structure, the atom utilization of platinum atoms is highly efficient. The X-ray photoelectron spectroscopy results indicate that partial electrons transfer from the iron oxides to Pt nanowalls, and this increases the electron density of snPt nanoparticles, thus promoting the catalytic activity for the transfer hydrogenation of nitroaromatics. For the reduction of 4-nitrophenol, the reaction rate constant K app is 0.23 min-1 and the turnover frequency (TOF) is up to 3062 h-1. Additional reaction results illustrate that this magnetic nanoreactor can be reused more than eight times and it is a promising catalytic nanoplatform in heterogeneous catalysis.

Optimized Co2+(Td)–O–Fe3+(Oh) electronic states in a spinel electrocatalyst for highly efficient oxygen evolution reaction performance

The introduction of iron into Co₃O₄ can induce a change in the electronic states of Co³⁺, which is an effective means to regulate the oxygen evolution reaction activity.