Structural Construction of Au-Pd Nanocomposite for Alkali-Free Oxidation of Benzyl Alcohol

A bimetallic Au-Pd system is an alternative candidate to catalyze primary alcohol oxidation and is of crucial importance for the sustainable chemical industry. However, understanding the bimetallic system in terms of the nanostructure is still challenging. Herein, we adopt the in situ colloid immobilization to obtain a series of bimetallic Au_xPd_y/CNT samples supported by carbon nanotubes (CNTs). Elaborate characterizations confirmed the bimetallic structure of AuPd alloy particles with randomly dispersed Pd²⁺ on the surface, forming the AuPd@PdO structure on CNTs. Unlike the monometallic samples, bimetallic ones, particularly Au₁Pd₁/CNT, efficiently transformed benzyl alcohol in an alkali-free mild condition. The DFT simulation confirmed the electron-rich gold atoms as a steric and electronic regulator to confine the electron-deficient Pd atoms in alloy particles. The interacted metal sites in the alloy system activated the alcohol with optimized adsorption configuration. Surface Pd²⁺ transported active oxygen to capture the abstracted H on alcohol. The collaboration between metal sites facilitated the transformation of benzyl alcohol to benzaldehyde with the selectivity of 91.8% by a fast TOF of 1274 h^-1 at only 80 °C.

Radial Nano-Heterojunctions Consisting of CdS Nanorods Wrapped by 2D CN:PDI Polymer with Deep HOMO for Photo-Oxidative Water Splitting, Dye Degradation and Alcohol Oxidation

Solar energy harvesting using semiconductor photocatalysis offers an enticing solution to two of the biggest societal challenges, energy scarcity and environmental pollution. After decades of effort, no photocatalyst exists which can simultaneously meet the demand for excellent absorption, high quantum efficiency and photochemical resilience/durability. While CdS is an excellent photocatalyst for hydrogen evolution, pollutant degradation and organic synthesis, photocorrosion of CdS leads to the deactivation of the catalyst. Surface passivation of CdS with 2D graphitic carbon nitrides (CN) such as g-C₃N₄ and C₃N₅ has been shown to mitigate the photocorrosion problem but the poor oxidizing power of photogenerated holes in CN limits the utility of this approach for photooxidation reactions. We report the synthesis of exfoliated 2D nanosheets of a modified carbon nitride constituted of tris-s-triazine (C₆N₇) linked pyromellitic dianhydride polydiimide (CN:PDI) with a deep oxidative highest occupied molecular orbital (HOMO) position, which ensures sufficient oxidizing power for photogenerated holes in CN. The heterojunction formed by the wrapping of mono-/few layered CN:PDI on CdS nanorods (CdS/CN:PDI) was determined to be an excellent photocatalyst for oxidation reactions including photoelectrochemical water splitting, dye decolorization and the photocatalytic conversion of benzyl alcohol to benzaldehyde. Extensive structural characterization using HR-TEM, Raman, XPS, etc., confirmed wrapping of few-layered CN:PDI on CdS nanorods. The increased photoactivity in CdS/CN:PDI catalyst was ascribed to facile electron transfer from CdS to CN:PDI in comparison to CdS/g-C₃N₄, leading to an increased electron density on the surface of the photocatalyst to drive chemical reactions.

Single-atom Ru loaded on layered double hydroxide catalyzes peroxymonosulfate for effective E. coli inactivation via a non-radical pathway: Efficiency and mechanism

The Fenton-like processes are considered to be one of the most promising strategies for inactivating bacteria due to their capacity to produce reactive oxygen species (ROS). Herein, a catalytic system for efficient inactivation of Escherichia coli (E. coli) was developed by anchoring single-atom Ru on layered double hydroxides (LDH). The Ru/NiFe-LDH catalyst showed excellent performance in activating peroxymonosulfate (PMS) to inactivate E. coli. Under the combined action of the ultra-low concentrations of Ru/NiFe-LDH (40 mg/L) and PMS (5 mg/L), 7 log E. coli can be totally inactivated within 90 s. This was attributed to the combined effect of single-atom Ru adsorption to E. coli and the ROS produced in situ. Mechanism studies indicated that the ¹O₂ with electrophilic properties was the key active species responsible for the rapid inactivation of E. coli. The E. coli inactivation process suggested that the ROS produced first attacked the outer membrane of the cell, then the antioxidant enzymes in the cell were induced, the macromolecule substances were released and mineralized, eventually leading to irreversible cell death. This work firstly loads monoatomic Ru on LDH for bacterial inactivation, providing a feasible method for rapid inactivation of E. coli.

Facet-engineering palladium nanocrystals for remarkable photocatalytic dechlorination of polychlorinated biphenyls

Rationally constructing functionalized cocatalysts for removing chemically inert polychlorinated biphenyls is significant and challenging.

Palladium Nanoparticles Supported on Cellulosic Paper as Multifunctional Catalyst for Coupling and Hydrogenation Reactions

Hallmark of a successful catalyst is its high efficiency, economic aspects, operational simplicity, extensive reusability, higher environment friendliness, and potential use in multiple industrial applications. Herein, a facile protocol involving a catalyst with Pd nanoparticles supported on cellulose paper (also known as a "dip-catalyst") for the hydrogenation of a series of quinolines, nitroarene, and C-C bond formation reactions in most benign solvents such as water is described. The mere insertion/removal of the "dip-catalyst" strip enables instantaneous start/stop of the reaction, which enhances its reusability and ease of separation of products. Cellulose paper (CP) strips decorated with Pd nanoparticles (Pd/CP) are prepared by the reduction of K₂ PdCl₄ soaked strips using formic acid as reductant. The resulting spherical shaped Pd particles, confirmed by scanning electron microscopy, form stable catalysis centers on the support. XRD signature confirms the crystallinity of the Pd nanoparticles and the TEM images display 15-20 nm size particles uniformly decorating CP. X-ray photoelectron spectroscopy indicates the formation of metallic Pd. The catalyst is tested for the C-C bond formation reactions. Pd/CP catalyzed Suzuki-Miyaura coupling reaction demonstrate >99% conversion with optimum selectivity. On the other hand, Mizoroki-Heck reaction produced 87% conversion with the reaction of 4-methoxycarbonyl phenylboronic acid and iodobenzene in ethanol:water (1 : 1 v/v) using KOH as base. The developed Pd/CP construct produces >99% of the pyridine-ring hydrogenated product on quinoline hydrogenation using tetrahydroxydiboron (THDB) as the hydrogen source. Diverse and highly reducible functional groups were also evaluated for transfer hydrogenation, which demonstrates a high efficiency in terms of both reactivity and selectivity. The used catalysts are recyclable for the multiple cycles.

Atomically Dispersed Ruthenium on Nickel Hydroxide Ultrathin Nanoribbons for Highly Efficient Hydrogen Evolution Reaction in Alkaline Media

Achieving highly efficient hydrogen evolution reaction (HER) in alkaline media is a great challenge. Single-atom catalysts with high-loading amount have attracted great interest due to their remarkable catalytic properties. Herein, by using nickel foam as the substrate, the authors design and precisely synthesize atomic ruthenium (Ru)-loaded nickel hydroxide ultrathin nanoribbons (R-NiRu) with a high atomic Ru loading amount reaching ≈7.7 wt% via a one-step hydrothermal method. The presence of concentrated Cl^- in the synthetic system is beneficial for constructing ultrathin nanoribbons, which, with abundant edge OH groups, make it easy to trap atomic Ru. Taking advantage of the synergy between atomic Ru and the nanoribbon morphology of nickel hydroxide, R-NiRu exhibit a low overpotential of 16 mV for HER at 10 mA cm^-2 and a Tafel slope of 40 mV dec^-1 in aqueous 1.0 m KOH solution, which are superior to those of commercial Pt/C (overpotential of 17 mV at 10 mA cm^-2 , Tafel slope of 43 mV dec^-1 ). Density functional theory (DFT) calculation results demonstrate that atomically dispersed Ru can significantly reduce the HER energy barrier. Moreover, R-NiRu maintains exceptional stability after 5000 cyclic voltammetry cycles. This efficient and facile synthetic strategy provides a new avenue for designing efficient catalysts.

Catalytic Oxidation of Benzyl Alcohol to Benzaldehyde on Au8 and Au6Pd2 Clusters: A DFT Study on the Reaction Mechanism

Density functional theory calculations were performed to investigate the reaction mechanism of the aerobic oxidation of benzyl alcohol to benzaldehyde catalyzed by Au and Au–Pd clusters. Two consecutive reaction mechanisms were examined with Au8 and Au6Pd2 clusters: (1) the oxidation of benzyl alcohol with dissociated O atoms on metal clusters generating benzaldehyde and H2O; and (2) oxidation with adsorbed oxygen molecules generating benzaldehyde and H2O2. The calculations show that the aerobic oxidation of benzyl alcohol energetically prefers to proceed in the former mechanism, which agrees with the experimental observation. We demonstrate that the role of Au centers around the activation of molecular oxygen to peroxide-like species, which are capable of the H–abstraction of benzyl alcohol. The roles of Pd in the Au6Pd2 cluster are: (1) increasing the electron distribution to neighboring Au atoms, which facilitates the activation of O2; and (2) stabilizing the adsorption complex and transition states by the interaction between positively charged Pd atoms and the π-bond of benzyl alcohol, both of which are the origin of the lower energy barriers than those of Au8.

Pulsed Laser in Liquids Made Nanomaterials for Catalysis

Catalysis is essential to modern life and has a huge economic impact. The development of new catalysts critically depends on synthetic methods that enable the preparation of tailored nanomaterials. Pulsed laser in liquids synthesis can produce uniform, multicomponent, nonequilibrium nanomaterials with independently and precisely controlled properties, such as size, composition, morphology, defect density, and atomistic structure within the nanoparticle and at its surface. We cover the fundamentals, unique advantages, challenges, and experimental solutions of this powerful technique and review the state-of-the-art of laser-made electrocatalysts for water oxidation, oxygen reduction, hydrogen evolution, nitrogen reduction, carbon dioxide reduction, and organic oxidations, followed by laser-made nanomaterials for light-driven catalytic processes and heterogeneous catalysis of thermochemical processes. We also highlight laser-synthesized nanomaterials for which proposed catalytic applications exist. This review provides a practical guide to how the catalysis community can capitalize on pulsed laser in liquids synthesis to advance catalyst development, by leveraging the synergies of two fields of intensive research.

Research Progress in Organic Synthesis by Means of Photoelectrocatalysis

The rapid development of radical chemistry has spurred several innovative strategies for organic synthesis. The novel approaches for organic synthesis play a critical role in promoting and regulating the single-electron redox activity. Among them, photoelectrocatalysis (PEC) has attained considerable attention as the most promising strategy to convert organic compounds into fine chemicals. This review highlights the current progress in organic synthesis through PEC, including various catalytic reactions, catalyst systems and practical applications. The numerous catalytic reactions suffer the high overpotential and poor conversion efficiency, depending on the design of electrolyzers and the reaction mechanisms. We also considered the recent developments with special emphasis on scientific problems and efficient solutions, which enhance accessibility to utilize and further develop the photoelectrocatalytic technology for the specific chemical bonds formation and the fabrication of numerous catalytic systems.

Ultrathin ZnTi-LDH nanosheets for photocatalytic aerobic oxidation of aniline based on coordination activation

Aniline is chemisorbed and activated on ultrathin ZnTi-LDH nanosheets, facilitating the photocatalytic aerobic oxidation of aniline under visible light.

Selectivity control of organic chemical synthesis over plasmonic metal-based photocatalysts

The factors, issues, and design of plasmonic metal-based photocatalysts for selective photosynthesis of organic chemicals have been discussed.

Exploiting the photocatalytic activity of TiO2 towards the depolymerization of Kraft lignin

Lignin is a promising renewable source of aromatic chemicals.

Visible-Light-Activated C-C Bond Cleavage and Aerobic Oxidation of Benzyl Alcohols Employing BiMXO5 (M=Mg, Cd, Ni, Co, Pb, Ca and X=V, P)

The synthesis, structure, optical and photocatalytic studies of a family of compounds with the general formula, BiMXO₅ ; M=Mg, Cd, Ni, Co, Pb, Ca and X=V, P is presented. The compounds were prepared by regular solid-state reaction of constituents in the temperature range of 720-810 °C for 24 h. The compounds were characterized by powder X-ray diffraction (PXRD) methods. The Rietveld refinement of the PXRD patterns have been carried out to establish the structure. The optical absorption spectra along with the colors in daylight have been explained employing the allowed d-d transition. In addition, the observed colors of some of the V⁵⁺ containing compounds were explained using metal-to-metal charge transfer (MMCT) from the partially filled transition-metal 3d orbitals to the empty 3d orbitals of V⁵⁺ ions. The near IR (NIR) reflectivity studies indicate that many compounds exhibit good NIR reflectivity, suggesting that these compounds can be employed as 'cool pigments'. The experimentally determined band gaps of the prepared compounds were found to be suitable to exploit them for visible light activated photocatalysis. Photocatalytic C-C bond cleavage of alkenes and aerobic oxidation of alcohols were investigated employing visible light, which gave good yields and selectivity. The present study clearly demonstrated the versatility of the Paganoite family of compounds (BiMXO₅ ) towards new colored inorganic materials, visible-light photocatalysts and 'cool pigments'.

Zn2+ stabilized Pd clusters with enhanced covalent metal-support interaction via the formation of Pd-Zn bonds to promote catalytic thermal stability

Pd-Based heterogeneous catalysts have been demonstrated to be efficient in numerous heterogeneous reactions. However, the effect of the support resulting in covalent metal-support interaction (CMSI) has not been researched sufficiently. In this work, a Lewis base is modulated over MgAl-LDH to investigate the support effects and it is further loaded with Pd clusters to research the metal-support interactions. MgAl-LDH with ultra-low Pd loading (0.0779%) shows CO conversion (55.0%) and dimethyl oxalate (DMO) selectivity (93.7%) for CO oxidative coupling to DMO, which was gradually deactivated after evaluation for 20 h. To promote the stability of Pd/MgAl-LDH, Zn2+ ions were introduced into the MgAl-LDH support to strengthen the CMSI by forming Pd-Zn bonds, which further increased the adsorption energy of the Pd clusters on ZnMgAl-LDH, and this was verified by X-ray absorption fine structure (XAFS) measurements and density functional theory (DFT) calculations. The stability of the Pd/ZnMgAl-LDH catalyst could be maintained for at least 100 h. This work highlights that covalent metal-support interactions can be strengthened by forming new metal-metal bonds, which could be extended to other systems for the stabilization of noble metals over supports.

High and reversible oxygen uptake in carbon dot solutions generated from polyethylene facilitating reactant-enhanced solar light harvesting

Solar-driven photocatalysis is emerging as a key chemical transformation strategy due to its favourable energy economy. However, in photocatalytic oxidation reactions where molecular oxygen (O2) is a reactant, achieving higher efficiency requires an O2-saturated environment in order to maintain a high oxygen level on the catalyst surface, necessitating an additional energy-consuming step of O2 separation from air. Here we show that in the presence of carbon quantum dots (CQDs), the oxygen content and the ability of O2 to diffuse in water increase significantly. We first demonstrate a novel strategy to convert several grams of polyethylene, a stubborn pollutant, into highly photoactive CQDs by stepwise dehydrogenation and graphitization. In a typical CQD concentration of ∼1 mg ml-1, the oxygen level in water reaches ∼640 μM, double that of pure water inferring an extremely high O2 content of ∼1 wt% associated with CQDs under ambient conditions. Therefore, when the CQDs were used to catalyze photo-oxidation of aromatic alcohols by sunlight, the efficiency was found higher than previous instances despite those employing high oxygen pressure, temperature and expensive materials. Besides waste polyethylene utilization, the uniqueness of oxygen enrichment in CQD solutions may offer immense prospects including those in photo-oxidation reactions.

Interfacial synergy between dispersed Ru sub-nanoclusters and porous NiFe layered double hydroxide on accelerated overall water splitting by intermediate modulation

Construction of an efficient bifunctional electrocatalyst through a rational interface-engineering strategy to optimize the adsorption energy of H* and OH* species at the atomic/molecular level is of great importance for water splitting. Although conventional NiFe layered double hydroxide (LDH) shows excellent performance for alkaline oxygen evolution reactions (OERs), it shows extremely poor activity toward hydrogen evolution reactions (HERs) due to weak hydrogen adsorption and sluggish kinetics. In this work, integration of sub-nanoscale Ru species with NiFe LDH can dramatically enhance the adsorption energy of H* and improve their HER kinetics. Besides, benefitting from the desired potential-induced strategy, the Ru-NiFe LDH interfaces will convert to RuO2-NiFe(OOH)x interfaces to optimize the adsorption energy of OH* to meet the requirement of strengthening the OER performance. Strikingly, the Ru-NiFe LDH-F/NF sample (NF: Ni foam) shows an excellent OER and HER performance with an overpotential of 230.0 mV and 115.6 mV at a current density of 10 mA cm-2, respectively, as well as outstanding durability. The overall water splitting device was fabricated by using Ru/NiFe LDH-F/NF as both the HER and OER electrode with a potential of 1.53 V to achieve a current density of 10 mA cm-2. In addition, the theoretical calculations demonstrated that the Ru-NiFe LDH interfaces could optimize the adsorption energy of H* and OH*. This study provides a new insight into the development of highly efficient bifunctional electrocatalysts for water electrolysis.

Strong pyrrolic-N-Pd interactions boost the electrocatalytic hydrodechlorination reaction on palladium nanoparticles

We demonstrated that heteroatomic nitrogen (N) doping of graphene can significantly enhance the performance of the graphene-palladium nanoparticle composite catalyst (N/G-Pd) in the electrocatalytic hydrodechlorination (EHDC) reaction. Specifically at -0.80 V (vs. Ag/AgCl), the N/G-430-Pd (prepared at 430 °C, pyridinic/pyrrolic-N-rich) and N/G-900-Pd (prepared at 900 °C, pyridinic/graphitic-N-rich) with equivalent total N content delivered the apparent rate constants (kobs) of 0.28 and 0.20 min-1 molPd-1 in removing 2,4-dichlorophenol, much higher than the 0.13 min-1 molPd-1 of the C-Pd. Additionally, we identified the determinant role of pyrrolic-N in boosting EHDC from the linear relationship between kobs-N and the pyrrolic-N content in the catalyst. Combined experimental and DFT analyses revealed that the positive effect of N doping originated from the strong N-Pd interactions, which modulated the Pd electronic structure and its interactions with the reactant and EHDC products (phenol and Cl-). The pyrrolic N-Pd bond was favorable as it could balance the reactant adsorption and the product desorption.

The synergistic role of the support surface and Au–Cu alloys in a plasmonic Au–Cu@LDH photocatalyst for the oxidative esterification of benzyl alcohol with methanol

The acid–base pairs of the support synergistic with Au–Cu alloy NPs could drive the oxidative esterification of benzyl alcohol with methanol.

O-MoS2/Mn0.5Cd0.5S composites with enhanced activity for visible-light-driven photocatalytic hydrogen evolution

The reaction mechanism of O-MoS₂/Mn_0.5Cd_0.5S for photocatalytic hydrogen evolution is put forward and the satisfactory hydrogen production rate of the optimized composite is superior to most of the Mn–Cd–S based catalysts reported.

An advanced composite with ultrafast photocatalytic performance for the degradation of antibiotics by natural sunlight without oxidizing the source over TMU-5@Ni–Ti LDH: mechanistic insight and toxicity assessment

Pharmaceuticals are considered as emerging organic contaminants that have become a serious environmental problem, which endanger human health and environmental bio-diversity.

Enhanced Heck reaction on flower-like Co(Mg or Ni)Al layered double hydroxide supported ultrafine PdCo alloy nanocluster catalysts: the promotional effect of Co

A series of PdCo alloy nanocluster (NC) catalysts x-PdCo_r/Co(Mg or Ni)Al-LDH (x: Pd loading, r: Co/Pd molar ratio) were synthesized by immobilizing ultrafine PdCo_r-PVP NCs on flower-like layered double hydroxide (LDH) supports. The sizes of PdCo alloy NCs of the catalysts can be elaborately tuned in ∼1.6-3.2 nm by both Co/Pd ratios and Pd loadings, and the PdCo NCs are mainly dispersed on the edge sites of LDH nanosheets upon a flower-like morphology. The PdCo bimetallic catalysts 0.81-PdCo_0.10/MgAl-LDH (2.6 ± 0.6 nm), 0.86-PdCo_0.28/MgAl-LDH (2.3 ± 0.7 nm) and 0.79-PdCo_0.54/MgAl-LDH (3.2 ± 0.9 nm) exhibit enhanced activity compared with the monometallic Pd catalyst for Heck coupling of iodobenzene with styrene. Particularly, 0.86-PdCo_0.28/MgAl-LDH shows the highest activity, which can be attributed to its smallest PdCo_0.28 alloy NCs, and the maximum electron density of the Pd⁰ center resulted from the electron transfer from Co and the strongest PdCo_0.28 NCs - LDH synergistic effect. 0.67-PdCo_0.28/CoAl-LDH shows much better activity than those of 0.64-PdCo_0.28/NiAl-LDH and 0.86-PdCo_0.28/MgAl-LDH. The lowest Pd loading sample 0.01-PdCo_0.28/CoAl-LDH (1.6 ± 0.4 nm) shows an ultrahigh turnover frequency of 163 000 h^-1 (Pd: 1.9 × 10^-5 mol%), which is the highest value obtained so far. Meanwhile, the catalyst shows excellent adaptability for the substrates and can be reused for 12 runs without significant loss of activity. The present work may provide a new idea for the simple and green synthesis of ultrafine Pd-based non-noble bimetallic catalysts for varied catalytic processes.

Pd Nanoparticles Supported on Amine-Functionalized MgAl Layered Double Hydroxides for Solvent-Free Aerobic Oxidation of Benzyl Alcohol

Pd nanoparticles (NPs) supported on amine-functionalized layered double hydroxides (LDHs) (Pd/NH2-LDH-NS) were successfully obtained by implanting aminopropyltriethoxysilane (APTS) on MgAl LDH nanosheets (LDH-NS), followed by impregnating [Pd(NH3)4]Cl2 and reduction with NaBH4. The physicochemical characteristics of the obtained Pd/NH2-LDH-NS were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR),, N2 adsorption–desorption, inductive coupled plasma (ICP), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy(XPS), and their catalytic performance was tested in the selective oxidation of benzyl alcohol with molecular oxygen under solvent-free and base-free conditions. The results showed that the implanted –NH2 groups can promote the dispersion of the supported Pd NPs via complexation of the implanted –NH2 groups to Pd NPs, and they can increase the surface basicity of the catalysts, thus enhancing the catalytic activity and selectivity to benzylaldehyde. Pd/NH2-LDH-NS exhibited enhanced catalytic activity (31.6%) and selectivity (>98%) compared to the corresponding Pd/LDH-NS, Pd/LDH, Pd/SiO2, and Pd/Al2O3. Moreover, Pd/NH2-LDH-NS was remarkably stable and could be reused at least four times without a significant loss in activity and selectivity.

Efficient thermal- and photocatalysts made of Au nanoparticles on MgAl-layered double hydroxides for energy and environmental applications

Composites of the noble metal Au supported on MgAl-LDHs were prepared by a simple impregnation-reduction method to be used as thermal- and photocatalysts for the photocatalytic degradation of ciprofloxacin and thermocatalytic decomposition of formic acid to produce hydrogen. A collection of techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to determine the structure and morphology properties of the as-prepared Au/MgAl-LDHs. The presence of surface Au(0) in Au/MgAl-LDHs was confirmed by TEM and XPS analyses. For the first time, we compared the effect of the surfactant PVP on the catalyst and found that the Au/MgAl-LDH composite with Au particle size of 2-8 nm had better catalytic activity than the (PVP@Au)/MgAl-LDH composite with Au particle size in the range of 1-5 nm. The sizes of Au NPs in the two catalysts were similar but had different effects on the catalytic performance. This indicated that the addition of PVP had an inhibitory effect on the catalytic activity of the catalyst. To evaluate the photostability of Au/MgAl-LDHs, recycle experiments for the photocatalytic degradation of ciprofloxacin were performed, and it was found that Au/MgAl-LDHs had good stability. Finally, we also applied Au/MgAl-LDHs in environmental catalysis and energy catalysis; we hope that they will be useful in practical applications.

Boosting oxygen evolution of single-atomic ruthenium through electronic coupling with cobalt-iron layered double hydroxides

Single atom catalyst, which contains isolated metal atoms singly dispersed on supports, has great potential for achieving high activity and selectivity in hetero-catalysis and electrocatalysis. However, the activity and stability of single atoms and their interaction with support still remains a mystery. Here we show a stable single atomic ruthenium catalyst anchoring on the surface of cobalt iron layered double hydroxides, which possesses a strong electronic coupling between ruthenium and layered double hydroxides. With 0.45 wt.% ruthenium loading, the catalyst exhibits outstanding activity with overpotential 198 mV at the current density of 10 mA cm^-2 and a small Tafel slope of 39 mV dec^-1 for oxygen evolution reaction. By using operando X-ray absorption spectroscopy, it is disclosed that the isolated single atom ruthenium was kept under the oxidation states of 4+ even at high overpotential due to synergetic electron coupling, which endow exceptional electrocatalytic activity and stability simultaneously.

Visible light promoted degradation of gaseous volatile organic compounds catalyzed by Au supported layered double hydroxides: Influencing factors, kinetics and mechanism

In this paper, factors of initial concentration, catalyst dosage, irradiation intensity, relative humidity and reaction temperature onto visible light gaseous o-xylene photodegradation by ZnCr layered double hydroxides (ZnCr-LDHs) and Au supported ZnCr-LDHs (Au/ZnCr-LDHs) were investigated. ZnCr-LDHs shows low removal efficiency for o-xylene photodegradation, while Au/ZnCr-LDHs exhibits both excellent photodegradation rate and high TOF values for o-xylene as well as other VOCs including benzene, o-xylene, m-xylene and p-xylene. The kinetic equation and activation energy were calculated for o-xylene photodegradation, which are [Formula: see text] and 21.85 kJ/mol for ZnCr-LDH [Formula: see text] and 12.84 kJ/mol for Au/ZnCr-LDHs. The obvious difference both in kinetic equation and activation energy suggests the reaction mechanism of ZnCr-LDHs and Au/ZnCr-LDHs should be very different. The active species inhabitation experiments show that the major drive of photocatalytic reaction for ZnCr-LDHs is hydroxyl radical, while for Au/ZnCr-LDHs it is the hole and hydroxide radical. It is also proved that the support of Au NPs onto LDHs would result in the transfer of photoexcited electrons from LDHs to Au NPs which results in the enhancement of photocatalytic property as well as photocatalytic mechanism change based on UV-vis, XPS, the contribution of different wavelength ranges of visible light onto photocatalytic efficiency and electrochemical tests.

Influence of Au/Pd alloy on an amine functionalised ZnCr LDH–MCM-41 nanocomposite: A visible light sensitive photocatalyst towards one-pot imine synthesis

Au/Pd loaded amine functionalised ZnCr LDH–MCM-41 photocatalyst for one-pot imine synthesis.

Fabrication of a Au-loaded CaFe2O4/CoAl LDH p–n junction based architecture with stoichiometric H2 & O2 generation and Cr(vi) reduction under visible light

Visible-light-efficient Au-loaded CaFe₂O₄/CoAl LDH p–n junction for H₂ & O₂ generation and Cr(vi) reduction.

A plasmonic AuPd bimetallic nanoalloy decorated over a GO/LDH hybrid nanocomposite via a green synthesis route for robust Suzuki coupling reactions: a paradigm shift towards a sustainable future

A plasmonic AuPd bimetal-decorated GO/LDH nano-photocatalyst displays encouraging Suzuki coupling performance under visible light illumination.

In Situ Growth of Pd Nanosheets on g-C3 N4 Nanosheets with Well-Contacted Interface and Enhanced Catalytic Performance for 4-Nitrophenol Reduction

Loading novel metal nanosheets onto nanosheet support can improve their catalytic performance, but the morphological incompatibility makes it difficult to construct a well-contacted interface, which is of particular interest in supported catalysts. Herein, Pd nanosheets (Pd NSs) are supported onto graphitic carbon nitride nanosheets (CNNSs) with intimate face-to-face contact through an in situ growth method. This method overcomes the limitations of the morphological incompatibility and ensures the intimate interfacial contact between Pd NSs and CNNSs. The nitrogen-rich nature of CNNSs endows Pd NSs with abundant anchoring sites, which optimizes the electronic structure and improves the chemical and morphological stability of Pd NSs. The supported Pd NSs demonstrate high dispersion and exhibit largely enhanced activity toward the reduction of 4-nitrophenol. The concentration-normalized rate constant is up to 3052 min-1 g-1 L, which is 5.4 times higher than that obtained by unsupported Pd NSs. No obvious deactivation is observed after six runs of the recycling experiments. It is believed that the supported novel metal nanosheets with the intimately contacted interface may show promising applications in catalysis.

Cobalt lactate complex as a hole cocatalyst for significantly enhanced photocatalytic H2 production activity over CdS nanorods

A cobalt lactate complex has been prepared in situ, which works as a molecular cocatalyst accelerating hole transfer for the enhanced photocatalytic H₂ evolution activity of CdS.

An amorphous CoSx modified Mn0.5Cd0.5S solid solution with enhanced visible-light photocatalytic H2-production activity

Amorphous noble metal-free CoS_x modified Mn_0.5Cd_0.5S with excellent photocatalytic hydrogen production activity has been successfully synthesized.