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Comprehensive Summary: An electrocatalytic multicomponent cascade cross‐coupling for the synthesis of chalcogenosulfonates has been established. This approach does not require the use of transition metals, acids, and external oxidants. The gentle conditions and tolerance to a wide variety of functional groups permit the derivatization of complex indoles. [ABSTRACT FROM AUTHOR]

Abstract The development of stable and efficient low‐cost electrocatalysts is conducive to the industrialization of CO2. The synergy effect between the heterogeneous interface of metal/oxide can promote the conversion of CO2. In this work, Cu2O/ZnO heterostructures with partially reduced metal/oxide heterointerfaces in Zn plates (CZZ) have been synthesized for CO2 electroreduction in different cationic solutions (K+ and Cs+). Physical characterizations were used to demonstrate the heterojunction of Cu2O/ZnO and the heterointerfaces of metal/oxide; electrochemical tests were used to illustrate the enhancement of the selectivity of CO2 to CO in different cationic solutions. Faraday efficiency for CO with CZZ as catalyst reaches 70.9% in K+ solution (current density for CO −3.77 mA cm−2 and stability 24 h), and the Faraday efficiency for CO is 55.2% in Cs+ solution (−2.47 mA cm−2 and 21 h). In addition, in situ techniques are used to elucidate possible reaction mechanisms for the conversion of CO2 to CO in K+ and Cs+ solutions.

High-entropy alloy nanoparticles (HEA-NPs) have recently sparked great interest in materials science. Their solid-solution states, derived from distinct HEA configurations, make them promising candidates for catalysts with exceptional activity, stability, and tunable performance. However, a comprehensive understanding of the underlying mechanisms governing their electrocatalytic behavior is still lacking, hindering the rational design of HEA electrocatalysts. This review summarizes the fundamental knowledge of HEA-NPs, including the structure-activity correlations of HEA-NPs, diverse synthesis strategies, and applications in electrochemical catalysis. The design strategies for guiding improvements in tunable performance were highlighted. The article concludes with insights, perspectives, and future directions, encapsulating the state-of-the-art knowledge and paving the way for further exploration in this dynamic field. [ABSTRACT FROM AUTHOR]

Efficient detection of chemical oxygen demand (COD) is crucial for effective pollution prevention. Traditional Cu‐based electrodes, widely utilized for COD sensors suffer from issues related to low activity and stability. This study introduced a novel approach by employing a copper foam‐supported metal‐organic frameworks (Cu‐MOF), synthesized through a solvothermal method, which is subsequently pyrolyzed to yield a carbon‐capsulated CuOx/Cu foam electrode. Cyclic voltammetry analysis demonstrated that the carbon‐capsulated CuOx/Cu foam electrode exhibited superior redox activity, notably generating an increased amount of Cu(III) species. This enhancement significantly contributed to the electrocatalytic oxidation of organic compounds. The developed electrode demonstrated a wide linear detection range of 5–600 ppm, with a low detection limit of 0.96 ppm (S/N=3) for COD sensing. Notably, the sensor exhibited excellent anti‐interference capabilities, desirable reproducibility, and stability. The proposed method was successfully applied to determine COD in real water samples. Comparative analysis with the standard potassium dichromate method revealed high accuracy and a low relative error (2.89 %–6.72 %). This innovative approach holds promise for rapid and accurate COD detection, presenting a valuable contribution to environmental monitoring and water quality assessment. [ABSTRACT FROM AUTHOR]

The exploration into nanomaterial-based nonenzymatic biosensors with superb performance in terms of good sensitivity and anti-interference ability in disease marker monitoring has always attained undoubted priority in sensing systems. In this work, we report the design and synthesis of a highly active nanocatalyst, i.e., palladium and platinum nanoparticles (Pt&Pd-NPs) decorated ultrathin nanoporous gold (NPG) film, which is modified on a homemade graphene paper (GP) to develop a high-performance freestanding and flexible nanohybrid electrode. Owing to the structural characteristics the robust GP electrode substrate, and high electrochemically catalytic activities and durability of the permeable NPG support and ultrafine and high-density Pt&Pd-NPs on it, the resultant Pt&Pd-NPs–NPG/GP electrode exhibits excellent sensing performance of low detection limitation, high sensitivity and anti-interference capability, good reproducibility and long-term stability for the detection of small molecular biomarkers hydrogen peroxide (H2O2) and glucose (Glu), and has been applied to the monitoring of H2O2 in different types of live cells and Glu in body fluids such as urine and fingertip blood, which is of great significance for the clinical diagnosis and prognosis in point-of-care testing. [ABSTRACT FROM AUTHOR]

Water oxidation is a multielectron complex reaction that produces molecular oxygen as the final product. The article addresses the lack of confirmation of oxygen product formation in electrochemical oxygen evolution reaction (OER) studies, despite the extensive research conducted on catalysts for water splitting. It critically evaluates the trend observed in many studies that solely rely on electrochemical methods for OER quantification without confirming the oxygen product via complementary analytical techniques. The omission of measuring evolved oxygen gas leaves a crucial gap in the quantification of the OER process and raises concerns about the validity and accuracy of reported results. Analytical techniques, such as gas chromatography, Rotating Ring-Disk Electrode (RRDE), fluorescence oxygen probes, Clark electrode, and volumetry are critically analyzed and described to ensure the reliability and credibility of voltammetry and bulk electrolysis to provide a more accurate assessment of the OER process. [ABSTRACT FROM AUTHOR]

Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions—a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed. [ABSTRACT FROM AUTHOR]

Emerging as a new class of advanced functional materials with hierarchical architectures and redox characters, organic–inorganic hybrid materials (OIHs) have been well developed and widely applied in various energy conversion reactions recently. In this review, we focus on the applications and structure–performance relationship of OIHs for electrochemical water oxidation. The general principles of water oxidation will be presented first, followed by the progresses on the applications of OIHs that are classified as metal organic frameworks (MOFs) and their derivates, covalent organic framework (COF)-based hybrids and other OIHs. The roles of organic counterparts on catalytic active centers will be fully discussed and highlighted with typical examples. Finally, the challenges and perspectives assessing this promising hybrid material as an electrocatalyst will be provided. [ABSTRACT FROM AUTHOR]

A method to access carbonyl compounds using reductive conditions was evaluated via electrochemical reduction of their corresponding N-benzyloxyphthalimide derivatives (NBOPIs). The mechanism of this originally reported electrochemical reaction was proposed based on DFT calculation and is experimentally confirmed herein, contrasting simulated and experimental cyclic voltammetry data. The reaction scope studied in a preparative scale and using redox sensitive functional groups showed good selectivity and tolerance toward oxidation under the reaction conditions with a moderate to good yield (50–71%). Nevertheless, some restrictions with reducible functional groups, like benzyl-brominated and nitro-aromatic derivatives, were observed. The present approach can be considered a self-sustainable electrochemical catalysis for the synthesis of aromatic carbonylic compounds passing through anion radical intermediates produced by a cathodic reaction.

The development of heterogeneous catalysts is one of the pillars of modern material science. Among all supports, carbonaceous ones are the most popular due to their high surface area, limited cost, and tunable properties. Nevertheless, materials such as carbon black are produced from oil-derived sources lacking in sustainability. Pyrolytic carbon produced from biomass, known as biochar, could represent a valid solution to combine the sustainability and performance of supported catalysts. In this review, we report a comprehensive overview of the most cutting-edge applications of biochar-based catalysts, providing a reference point for both experts and newcomers. This review will provide a description of all possible applications of biochar-based catalysts, proving their sustainability for the widest range of processes. [ABSTRACT FROM AUTHOR]

The ethylenediamine-N,N′-disuccinic acid (EDDS) was utilized to form Fe-EDDS complex to activate peroxymonosulfate (PMS) in the electrochemical (EC) co-catalytic system for effective oxidation of naphthenic acids (NAs) under neutral pH conditions. 1-adamantanecarboxylic acid (ACA) was used as a model compound to represent NAs, which are persistent pollutants that are abundantly present in oil and gas field wastewater. The ACA degradation rate was significantly enhanced in the EC/PMS/Fe(III)-EDDS system (96.6%) compared to that of the EC/PMS/Fe(III) system (65.4%). The addition of EDDS led to the formation of a stable complex of Fe-EDDS under neutral pH conditions, which effectively promoted the redox cycle of Fe(III)-EDDS/Fe(II)-EDDS to activate PMS to generate oxidative species for ACA degradation. The results of quenching and chemical probe experiments, as well as electron paramagnetic resonance (EPR) analysis, identified significant contributions of •OH, 1O2, and SO4•− in the removal of ACA. The ACA degradation pathways were revealed based on the results of high resolution mass spectrometry analysis and calculation of the Fukui index. The presence of anions, such as NO3−, Cl−, and HCO3−, as well as humic acids, induced nonsignificant influence on the ACA degradation, indicating the robustness of the current system for applications in authentic scenarios. Overall results indicated the EC/PMS/Fe(III)-EDDS system is a promising strategy for the practical treatment of NAs in oil and gas field wastewater. [ABSTRACT FROM AUTHOR]

Producing hydrogen peroxide (H2O2) through an electrochemical oxygen reduction reaction (ORR) is a safe, green strategy and a promising alternative to traditional energy-intensive anthraquinone processes. Air and renewable power could be utilized for on-site and decentralized H2O2 production, demonstrating significant application potential. Currently, single atom catalysts (SACs) have demonstrated significant advantages in the catalytic production of H2O2 in 2e− ORR. However, the selectivity of SACs in ORR once puzzled researchers. This article reviews the research on the development and achievements of H2O2 production by SACs catalysis in recent years. Especially, the structure–performance relationship is a guide to designing new SACs. Combining advanced characterization techniques and theoretical calculation methods, researchers have a clearer and more thorough understanding of the impact of the atomic interface of SACs on ORR catalytic performance. The coordination moiety formed between the active metal center atom and the support seriously determines the selectivity of SACs, mainly manifested in the adsorption of *OOH intermediates. Particularly, the atomic interface of metal atoms together with O/N co-coordination exhibit high selectivity and mass activity, and heteroatoms or functional groups on carbon supports present synergistic effects to promote the production of H2O2 in 2e− ORR. Fine and accurate regulation of the atomic interface of SACs directly affects the 2e− ORR performance of the catalysts. Therefore, it is important to deeply understand the atomic interface of SACs and contribute to the development of novel catalysts. [ABSTRACT FROM AUTHOR]

Highlights Synthetic mechanisms of shape-controlled Pt-based alloy and intermetallic nanocrystals are outlined, and strategies for the design and development of morphology-controlled Pt-based nanostructures are discussed. Advanced characterizations and electrochemical applications of these Pt-based nanocatalysts are highlighted. Advances and perspectives in designing outperformance and the long-durability of Pt-based nanocatalysts with shape control in this electrochemical field are proposed.

The exploration into nanomaterial-based nonenzymatic biosensors with superb performance in terms of good sensitivity and anti-interference ability in disease marker monitoring has always attained undoubted priority in sensing systems. In this work, we report the design and synthesis of a highly active nanocatalyst, i.e., palladium and platinum nanoparticles (Pt&Pd-NPs) decorated ultrathin nanoporous gold (NPG) film, which is modified on a homemade graphene paper (GP) to develop a high-performance freestanding and flexible nanohybrid electrode. Owing to the structural characteristics the robust GP electrode substrate, and high electrochemically catalytic activities and durability of the permeable NPG support and ultrafine and high-density Pt&Pd-NPs on it, the resultant Pt&Pd-NPs–NPG/GP electrode exhibits excellent sensing performance of low detection limitation, high sensitivity and anti-interference capability, good reproducibility and long-term stability for the detection of small molecular biomarkers hydrogen peroxide (H2O2) and glucose (Glu), and has been applied to the monitoring of H2O2 in different types of live cells and Glu in body fluids such as urine and fingertip blood, which is of great significance for the clinical diagnosis and prognosis in point-of-care testing.

[Display omitted] • Honeycomb-like CuO@C catalysts are fabricated via a simple polymer thermal treatment strategy. • CuO@C-600 achieves an overall FE of up to 77.1% at −1.2 V vs. RHE, with a FE towards C 2 H 4 approaching 60.2%. • The synergistic effect of CuO nanoparticles and amorphous carbon has the potential to accelerate charge transfer and thus enhance C 2 H 4 selectivity. The electrochemical CO 2 reduction (ECR) of high-value multicarbon products is an urgent challenge for catalysis and energy resources. Herein, we reported a simple polymer thermal treatment strategy for preparing honeycomb-like CuO@C catalysts for ECR with remarkable C 2 H 4 activity and selectivity. The honeycomb-like structure favored the enrichment of more CO 2 molecules to improve the CO 2 -to-C 2 H 4 conversion. Further experimental results indicate that the CuO loaded on amorphous carbon with a calcination temperature of 600 °C (CuO@C-600) has a Faradaic efficiency (FE) as high as 60.2% towards C 2 H 4 formation, significantly outperforming pure CuO-600 (18.3%), CuO@C-500 (45.1%) and CuO@C-700 (41.4%), respectively. The interaction between the CuO nanoparticles and amorphous carbon improves the electron transfer and accelerates the ECR process. Furthermore, in situ Raman spectra demonstrated that CuO@C-600 can adsorb more adsorbed *CO intermediates, which enriches the C C coupling kinetics and promotes C 2 H 4 production. This finding may offer a paradigm to design high-efficiency electrocatalysts, which can be beneficial to achieve the "double carbon goal." [ABSTRACT FROM AUTHOR]

[Display omitted] Metal-organic frameworks (MOFs) hold potential for promoting the redox reaction of sulfur species (RRS) and suppressing the shuttle effect in lithium–sulfur batteries (LSBs). However, except for a limited number of frameworks, most MOFs are found to be inert in accelerating RRS, which is largely related to the fact that their design principles and mechanism of catalysis have not been fully understood. Systematic density functional theory (DFT) calculations and experimental results reveal that the lack of exposed polar catalytic sites restricts MOF's potential in promoting RRS. Herein, based on a series of multivariable MOFs containing ligands with different thermal stability, selective ligand removal and ligand exchange (LE) strategies were applied successively to expose the catalytic metal clusters and introduce extra adsorption sites, rendering inert MOFs into catalytic ones. Such post-modified multivariable MOFs were shown to yield LSBs with remarkably improved specific capacity and cycling stability realizing 7.9 mAh cm−2 of capacity after 100 cycles at high sulfur loading of 8.1 mg·cm−2 under a lean electrolyte condition. The universal strategy proposed in this work will guide the design of catalytic MOFs for RRS and promote the development of advanced catalysts for high-performance LSBs. [ABSTRACT FROM AUTHOR]

Abstract Catalysis has been regarded as an effective strategy to mitigate sluggish reaction kinetics and serious shuttle effect of Li–S batteries. Herein, a spherical structure consists of ultrathin layered Ti3C2T x -TiN heterostructures (MX-TiN) through in-situ nitridation method is reported. Through controllable nitridation, highly conductive TiN layer grew on the surface and close coupled with interior MXene to form unique 2D heterostructures. The ultrathin heterostructure with only several nanometers in thickness enables outstanding ability to shorten electrons diffusion distance during electrochemical reactions and enlarge active surface with abundant adsorptive and catalytic sites. Moreover, the (001) surface of TiN is dominated by metallic Ti–3d states, which ensures fast transmitting electrons from high conductive MX-TiN matrix and thus guarantees efficient catalytic performance. Calculations and experiments demonstrate that polysulfides are strongly immobilized on MX-TiN, meanwhile the bidirectional reaction kinetics are catalytically enhanced by reducing the conversion barrier between liquid LiPSs and solid Li2S2/Li2S. As a result, the S/MX-TiN cathode achieves excellent long-term cyclability with extremely low-capacity fading rate of 0.022% over 1000 cycles and remarkable areal capacity of 8.27 mAh cm−2 at high sulfur loading and lean electrolytes. Graphical abstract

The electrodeposition method was firstly applied to obtain uniform cube‐shaped copper nanoparticles on conductive glass (ITO), and then a layer of tiny nickel nanoparticles. A bimetallic composite electrode (Cu−Ni/ITO), characterized by TEM, XPS and XRD, was prepared to construct the non‐enzyme electrochemical glucose sensor with high catalytic activity. The catalytic performance of Cu−Ni/ITO had been greatly improved, probably due to the synergistic bimetallic catalysis effect. The electrode had a satisfactory linear response in the range of 2.5×10−7 M to 2.6×10−3 M, with detection limit as low as 67 nM. Besides, Cu−Ni/ITO had good anti‐interference ability and reproducibility, indicating the promising application for glucose detection in practical samples. [ABSTRACT FROM AUTHOR]

Highlights: Synthetic mechanisms of shape-controlled Pt-based alloy and intermetallic nanocrystals are outlined, and strategies for the design and development of morphology-controlled Pt-based nanostructures are discussed. Advanced characterizations and electrochemical applications of these Pt-based nanocatalysts are highlighted. Advances and perspectives in designing outperformance and the long-durability of Pt-based nanocatalysts with shape control in this electrochemical field are proposed. To achieve environmentally benign energy conversion with the carbon neutrality target via electrochemical reactions, the innovation of electrocatalysts plays a vital role in the enablement of renewable resources. Nowadays, Pt-based nanocrystals (NCs) have been identified as one class of the most promising candidates to efficiently catalyze both the half-reactions in hydrogen- and hydrocarbon-based fuel cells. Here, we thoroughly discuss the key achievement in developing shape-controlled Pt and Pt-based NCs, and their electrochemical applications in fuel cells. We begin with a mechanistic discussion on how the morphology can be precisely controlled in a colloidal system, followed by highlighting the advanced development of shape-controlled Pt, Pt-alloy, Pt-based core@shell NCs, Pt-based nanocages, and Pt-based intermetallic compounds. We then select some case studies on models of typical reactions (oxygen reduction reaction at the cathode and small molecular oxidation reaction at the anode) that are enhanced by the shape-controlled Pt-based nanocatalysts. Finally, we provide an outlook on the potential challenges of shape-controlled nanocatalysts and envision their perspective with suggestions. [ABSTRACT FROM AUTHOR]

Using pyrrole and terephthalaldehyde as raw materials, porphyrin-conjugated microporous polymer (CMP) without metal centers in the porphyrin ring was synthesized directly via the one-step method. The polymer was carbonized at different temperatures to obtain a series of carbonaceous nanospheres C-CMP-x (x is the pyrolysis temperature), of which C-CMP-900 is a multifunctional electrochemical catalyst with excellent performance. Compared to the uncarbonized polymer, C-CMP-900 is more sensitive and efficient for the reduction of nitrobenzene and exhibits a lower limit of detection. There was a significant improvement in the performance of nitrobenzene reduction over nonmetallic catalysts described in the literature. Moreover, the catalyst also shows excellent oxygen evolution reaction (OER) electrocatalytic activity, with lower overpotential than commercial RuO2. Even after long cycling tests, the catalyst maintained good activity. The catalyst, with an ultralow detection limit for nitrobenzene reduction and excellent OER activity, may be attributed to its high specific surface area and special porous carbon structure based on the porphyrin skeleton. [ABSTRACT FROM AUTHOR]

Water oxidation is a multielectron complex reaction that produces molecular oxygen as the final product. The article addresses the lack of confirmation of oxygen product formation in electrochemical oxygen evolution reaction (OER) studies, despite the extensive research conducted on catalysts for water splitting. It critically evaluates the trend observed in many studies that solely rely on electrochemical methods for OER quantification without confirming the oxygen product via complementary analytical techniques. The omission of measuring evolved oxygen gas leaves a crucial gap in the quantification of the OER process and raises concerns about the validity and accuracy of reported results. Analytical techniques, such as gas chromatography, Rotating Ring-Disk Electrode (RRDE), fluorescence oxygen probes, Clark electrode, and volumetry are critically analyzed and described to ensure the reliability and credibility of voltammetry and bulk electrolysis to provide a more accurate assessment of the OER process.

Microbial cell factories offer an eco-friendly alternative for transforming raw materials into commercially valuable products because of their reduced carbon impact compared to conventional industrial procedures. These systems often depend on lignocellulosic feedstocks, mainly pentose and hexose sugars. One major hurdle when utilizing these sugars, especially glucose, is balancing carbon allocation to satisfy energy, cofactor, and other essential component needs for cellular proliferation while maintaining a robust yield. Nearly half or more of this carbon is inevitably lost as CO2 during the biosynthesis of regular metabolic necessities. This loss lowers the production yield and compromises the benefit of reducing greenhouse gas emissions—a fundamental advantage of biomanufacturing. This review paper posits the perspectives of using CO2 from the atmosphere, industrial wastes, or the exhausted gases generated in microbial fermentation as a feedstock for biomanufacturing. Achieving the carbon-neutral or -negative goals is addressed under two main strategies. The one-step strategy uses novel metabolic pathway design and engineering approaches to directly fix the CO2 toward the synthesis of the desired products. Due to the limitation of the yield and efficiency in one-step fixation, the two-step strategy aims to integrate firstly the electrochemical conversion of the exhausted CO2 into C1/C2 products such as formate, methanol, acetate, and ethanol, and a second fermentation process to utilize the CO2-derived C1/C2 chemicals or co-utilize C5/C6 sugars and C1/C2 chemicals for product formation. The potential and challenges of using CO2 as a feedstock for future biomanufacturing of fuels and chemicals are also discussed.

Dual catalysis is one of the most powerful strategies for the development of chemical reactions in organic synthesis. This strategy can be divided into cooperative catalysis, relay catalysis, and sequential catalysis according to the actual mode of operation and the communication between the catalysts. In recent years, such strategy has been applied in a large number of studies since it has the advantages of: 1) increasing reactivity and enabling challenging transformations; 2) offering a powerful way of controlling the stereoselectivity of asymmetric reactions, which is challenging for traditional catalytic systems; 3) catalyze the stereodivergent synthesis of molecules bearing one or more stereocenters from the same starting materials. This Perspective, which intends to introduce the reader to EurJOC special collection on Dual Catalysis , aims to summarize and introduce the different categories of dual catalysis and demonstrate their benefits in constructing new chemical bonds in a selective manner. Finally, current challenges and new trends in dual catalysis will be also presented. [ABSTRACT FROM AUTHOR]

As a typical VOCs emitted from petrochemical industry, chlorobenzene was selected to study its removal by wet oxidation with electrochemical catalysis. Ti based IrO 2 -Ta 2 O 5 electrode was used in the advanced oxidation of chlorobenzene, and Sn, Sb, Pt and La were used to modify Ti/IrO 2 -Ta 2 O 5. Ti/IrO 2 -Ta 2 O 5 -La showed the highest removal rate of chlorobenzene and it reached 99.2 % for the chlorobenzene oxidation, which was 20 % higher than those of the other 3 additions. Oxygen evolution overpotential of Ti/IrO 2 -Ta 2 O 5 -La increased to 1.17 V when compared with Ti/IrO 2 -Ta 2 O 5 of 1.08 V. EPR tests for free radicals and GC-MS tests for intermediates showed that the main active substance was · OH, and the element Cl in chlorobenzene dissociated from the benzene ring under the action with · OH to form · Cl and ClO · radicals. Degradation pathway of chlorobenzene was figured out as chlorobenzene→ phenols→ organic acids→ CO 2 +H 2 O. [Display omitted] • CB oxidation and mineralization rates reached 98.94 % and 87.77 %. • La Modified Ti/IrO 2 -Ta 2 O 5 raised reaction rate by 4 times. • The main active substance was · OH, and some active chlorine existed. • The current efficiency reached more than 9 %. [ABSTRACT FROM AUTHOR]

Emerging as a new class of advanced functional materials with hierarchical architectures and redox characters, organic–inorganic hybrid materials (OIHs) have been well developed and widely applied in various energy conversion reactions recently. In this review, we focus on the applications and structure–performance relationship of OIHs for electrochemical water oxidation. The general principles of water oxidation will be presented first, followed by the progresses on the applications of OIHs that are classified as metal organic frameworks (MOFs) and their derivates, covalent organic framework (COF)-based hybrids and other OIHs. The roles of organic counterparts on catalytic active centers will be fully discussed and highlighted with typical examples. Finally, the challenges and perspectives assessing this promising hybrid material as an electrocatalyst will be provided.

The development of heterogeneous catalysts is one of the pillars of modern material science. Among all supports, carbonaceous ones are the most popular due to their high surface area, limited cost, and tunable properties. Nevertheless, materials such as carbon black are produced from oil-derived sources lacking in sustainability. Pyrolytic carbon produced from biomass, known as biochar, could represent a valid solution to combine the sustainability and performance of supported catalysts. In this review, we report a comprehensive overview of the most cutting-edge applications of biochar-based catalysts, providing a reference point for both experts and newcomers. This review will provide a description of all possible applications of biochar-based catalysts, proving their sustainability for the widest range of processes.

The ethylenediamine-N,N′-disuccinic acid (EDDS) was utilized to form Fe-EDDS complex to activate peroxymonosulfate (PMS) in the electrochemical (EC) co-catalytic system for effective oxidation of naphthenic acids (NAs) under neutral pH conditions. 1-adamantanecarboxylic acid (ACA) was used as a model compound to represent NAs, which are persistent pollutants that are abundantly present in oil and gas field wastewater. The ACA degradation rate was significantly enhanced in the EC/PMS/Fe(III)-EDDS system (96.6%) compared to that of the EC/PMS/Fe(III) system (65.4%). The addition of EDDS led to the formation of a stable complex of Fe-EDDS under neutral pH conditions, which effectively promoted the redox cycle of Fe(III)-EDDS/Fe(II)-EDDS to activate PMS to generate oxidative species for ACA degradation. The results of quenching and chemical probe experiments, as well as electron paramagnetic resonance (EPR) analysis, identified significant contributions of •OH, 1O2, and SO4•− in the removal of ACA. The ACA degradation pathways were revealed based on the results of high resolution mass spectrometry analysis and calculation of the Fukui index. The presence of anions, such as NO3−, Cl−, and HCO3−, as well as humic acids, induced nonsignificant influence on the ACA degradation, indicating the robustness of the current system for applications in authentic scenarios. Overall results indicated the EC/PMS/Fe(III)-EDDS system is a promising strategy for the practical treatment of NAs in oil and gas field wastewater.

The development of low-alcohol liquor (Baijiu) can represent a tool to solve the problems of excessive alcohol intake. However, low-alcohol liquor has an insufficient ester aroma and a bland taste due to the alcohol dilution process. This study proposes an electrochemical catalysis technology to catalyze the esterification reaction between the acid and alcohol in liquor, thereby enhancing the ester aroma of low-alcohol liquor. In the electrochemical conversion process, the gold electrode with a certain potential promotes the formation of carbocation intermediate from corresponding carboxylic acid, thereby improving the esterification reaction efficiency. The key finding is that the total ester content of liquor treated using this technology is increased by more than 20%, and a strong ester aroma is attained. This study clarifies the electrocatalytic mechanism of the esterification reaction in liquor, and provides a new idea for making low-alcohol liquor become more attractive for aroma and taste aspects trying to obtain an alternative product contributing to the public health.

The research in graphdiyne (GDY) has experienced a rapid growth period in the first decade after its birth. As a new two-dimensional (2D) atomic crystal, GDY has unique structures consisting of both sp and sp2 hybridized carbon atoms, and exhibits many unprecedented intrinsic properties to scientists. Due to the inherent characteristics of GDY, some new phenomena and properties have been discovered in a wide range of research fields. GDY has made substantial breakthroughs in fundamental and applied science, formed innovative scientific concepts, and made great achievements. In these fields, the electrochemical energy storage and conversion are two important and impressive fields for the fundamental applicative investigations. This review focuses on the utilization of GDY as advanced electrochemical interface for the electrochemical energy storage and conversion. It begins with an introduction of the superiorities and inherent compatibilities of GDY as the electrochemical interface. Then, GDY's recent achievements in electrochemical storage and conversion are commented, from which we can appreciate the inherent advantages of GDY as a crucial material for alternating and innovating the electrochemical interface. Finally, new insights into the challenges and further perspectives on the GDY interface for the electrochemical energy storage and conversion are discussed, aiming at prompting in-depth investigation and their performance in practical applications.

Highlights: An in-situ strategy to synthesize ultrathin two-dimensional MXene-TiN heterostructures and the ultrathin structure extremely shortens the electrons diffusion distance from catalysts to active sulfur species. The heterostructure exhibits superior electronic structures to strongly capture the polysulfides and enhance bidirectional electrocatalytic ability between LiPSs and Li2S. The advanced cathode achieves an excellent long-term cyclability with an extremely low-capacity fading rate of 0.022% over 1000 cycles and a remarkable areal capacity of 8.27 mAh cm−2 at high sulfur loading of 10.16 mg cm−2. Catalysis has been regarded as an effective strategy to mitigate sluggish reaction kinetics and serious shuttle effect of Li–S batteries. Herein, a spherical structure consists of ultrathin layered Ti3C2Tx-TiN heterostructures (MX-TiN) through in-situ nitridation method is reported. Through controllable nitridation, highly conductive TiN layer grew on the surface and close coupled with interior MXene to form unique 2D heterostructures. The ultrathin heterostructure with only several nanometers in thickness enables outstanding ability to shorten electrons diffusion distance during electrochemical reactions and enlarge active surface with abundant adsorptive and catalytic sites. Moreover, the (001) surface of TiN is dominated by metallic Ti–3d states, which ensures fast transmitting electrons from high conductive MX-TiN matrix and thus guarantees efficient catalytic performance. Calculations and experiments demonstrate that polysulfides are strongly immobilized on MX-TiN, meanwhile the bidirectional reaction kinetics are catalytically enhanced by reducing the conversion barrier between liquid LiPSs and solid Li2S2/Li2S. As a result, the S/MX-TiN cathode achieves excellent long-term cyclability with extremely low-capacity fading rate of 0.022% over 1000 cycles and remarkable areal capacity of 8.27 mAh cm−2 at high sulfur loading and lean electrolytes. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) are often believed to play a significant role in antimicrobial actions of inorganic materials. However, processes to generate ROS, in particular charge transfer routes, remain unclear and warrant further study. Building a dual‐electrochemical workstation setup, herein we interpreted ROS‐related cytotoxicity by monitoring oxygen reduction reactions on materials' surfaces. We found that inorganic substances can gain electrons from surrounding microbes and donate them to molecular oxygen. The cytotoxicity property is thus highly associated with materials' electrocatalytic activity and selectivity towards oxygen reduction reaction (ORR). We assessed various of inorganic substances, such as ZnO, Ag, Au, Pt, and TiO2, with results in good agreement on their apparent cytotoxicity. Our electrochemical method explored a unique route to access materials' ROS‐related cytotoxicity. This will not only allow to fast screen antimicrobial agents among massive samples, but also enhance many ROS‐involved applications by generating ROS on purpose. [ABSTRACT FROM AUTHOR]

Future energy demands for green hydrogen have fueled intensive research on proton‐exchange membrane water electrolyzers (PEMWE). However, the sluggish oxygen evolution reaction (OER) and highly corrosive environment on the anode side narrow the catalysts to be expensive Ir‐based materials. It is very challenging to develop cheap and effective OER catalysts. Herein, Co‐hexamethylenetetramine metal–organic framework (Co‐HMT) as the precursor and a fast‐quenching method is employed to synthesize RuO2 nanorods loaded on antimony‐tin oxide (ATO). Physical characterizations and theoretical calculations indicate that the ATO can increase the electrochemical surface areas of the catalysts, while the tensile strains incorporated by quenching can alter the electronic state of RuO2. The optimized catalyst exhibits a small overpotential of 198 mV at 10 mA cm−2 for OER, and keeps almost unchanged after 150 h chronopotentiometry. When applied in a real PEMWE assembly, only 1.51 V is needed for the catalyst to reach a current density of 1 A cm−2. [ABSTRACT FROM AUTHOR]

Nanosized tungsten carbide (WC)/carbon (C) catalyst was synthesized via a novel ultra-rapid confinement combustion synthesis method. The amount of activated carbon (AC) plays an important role in the morphology and structure, controlling both the precursor and final powder. The WC particles synthesized inside the pores of the AC had been 10–20 nm because of the confinement of the pore structure and the large specific surface area of AC. When used for oxygen reduction performance, the half-wave potential was −0.24 V, and the electron transfer number was 3.45, indicating the main reaction process was the transfer of four electrons. The detailed electrocatalytic performance and underlying mechanism were investigated in this work. Our study provides a novel approach for the design of catalysts with new compositions and new structures, which are significant for promoting the commercialization of fuel cells. [ABSTRACT FROM AUTHOR]

Abstract Future energy demands for green hydrogen have fueled intensive research on proton‐exchange membrane water electrolyzers (PEMWE). However, the sluggish oxygen evolution reaction (OER) and highly corrosive environment on the anode side narrow the catalysts to be expensive Ir‐based materials. It is very challenging to develop cheap and effective OER catalysts. Herein, Co‐hexamethylenetetramine metal–organic framework (Co‐HMT) as the precursor and a fast‐quenching method is employed to synthesize RuO2 nanorods loaded on antimony‐tin oxide (ATO). Physical characterizations and theoretical calculations indicate that the ATO can increase the electrochemical surface areas of the catalysts, while the tensile strains incorporated by quenching can alter the electronic state of RuO2. The optimized catalyst exhibits a small overpotential of 198 mV at 10 mA cm−2 for OER, and keeps almost unchanged after 150 h chronopotentiometry. When applied in a real PEMWE assembly, only 1.51 V is needed for the catalyst to reach a current density of 1 A cm−2.

A novel electrochemically assisted cycloaddition process is proposed, in which highly efficient coupling of CO2 with styrene oxide (SO) can be achieved to form styrene carbonate (SC) as a high‐value‐added product. A series of Cu catalysts with different morphologies and chemical states were fabricated on carbon paper (CP) by using in‐situ electrodeposition, and the sample with nano‐dendrimer structure was found to exhibit a relatively high activity of 74.8 % SC yield with 92.7 % SO conversion under gentle reaction conditions, thus showing its potential for practical applications. The relatively high electrochemically active surface area and charge transfer ability of dendrimer‐like Cu benefited the electrochemical reaction. In particular, the Cu2+ species that were formed in situ during the reaction played a vital role in enhancing the activity and selectivity of the proposed Cu/CP hybrid catalyst. Cu2+ atoms served as active sites that can not only electrochemically activate CO2 but also facilitate the ring opening of SO. Mechanistic analysis suggested that the reaction followed electrochemical and liquid‐phase heterogeneous paths, which provide a new green and sustainable route for efficient utilization of CO2 resources for fine chemical electrosynthesis. [ABSTRACT FROM AUTHOR]

Hydrodefluorination (HDF) is a very important fundamental transformation for conversion of the C−F bond into the C−H bond in organic synthesis. In the past decade, much progress has been achieved with HDF through the utility of low‐valent metals, transition‐metal complexes and main‐group Lewis acids. Recently, novel methods have been introduced for this purpose through photo‐ and electrochemical pathways, which are of great significance, due to their considerable environmental and economical advantages. This Review highlights the HDF of fluorinated organic compounds (FOCs) through photo‐ and electrochemical strategies, along with mechanistic insights. [ABSTRACT FROM AUTHOR]

A long‐time challenge in aqueous CO2 electrochemical reduction is to catalyze the formation of products beyond carbon monoxide with selectivity. Formaldehyde is the simplest of these products and one of the most relevant due to its broad use in the industry. Paradoxically it is one of the less reported product. Such scarcity may be in part explained by difficult identification and quantification using conventional chromatography or proton nuclear magnetic resonance techniques. Likewise, indirect detection methods are usually not compatible with labelled studies for asserting product origin. Recently, the possible production of formaldehyde during electrochemical reduction of carbon monoxide to methanol at cobalt phthalocyanine molecular catalyst in basic media has been the object of contradictory reports. By applying an analytical procedure based on proton NMR along with labelled studies, we provide definitive evidence for HCHO formation. We have further identified the possible scenarios for methanol formation through formaldehyde and revealed that the formation of the intermediate and its subsequent reduction are taking place at the same single active site. These studies open a new perspective to improve selectivity toward formaldehyde formation and to develop a subsequent chemistry based on reacting it with nucleophiles. [ABSTRACT FROM AUTHOR]

• The ammonia removal efficiency of Fe/TiO 2 under 2 V VS Ag/AgCl during 2 h is 100 % and 94 % of ammonia is converted to N 2. • The non-noble metal Fe decorated anodes (Fe/TiO 2) show higher catalytic activity, great stability and reusability. • The mechanism for ammonia on TiO 2 , Fe/TiO 2 and Ir/TiO 2 are studied by density functional calculation. • Fe/TiO 2 anodes exhibits the best treatment effect on simulated real water for ammonia removal, which is beneficial to future water treatment process. Electrochemical ammonia oxidation process through active chlorine has been proposed as a potentially effective method for ammonia removal. Currently, most of the anodes require to use high-stable TiO 2 loaded with large particles of noble metal Ru or Ir, which have low activity and high cost. Herein, we prepare ultrasmall and uniform metal nanoparticles of Ir on TiO 2 to remove ammonia. Moreover, we use non-noble metal Fe to replace noble metals. The ammonia removal efficiency of Fe/TiO 2 under 2 V VS Ag / AgCl during 2 h is 100 % and 94 % of ammonia is converted to N 2. The Fe/TiO 2 anodes not only have higher catalytic activity but also show excellent stability and reusability. Fe/TiO 2 anodes still exhibit excellence activity and selectivity after 1 year. As a common metal, Fe will have more application space than iridium in ammonia removal for its low cost and selectively high efficiency. [ABSTRACT FROM AUTHOR]

This study examines the use of tetrabutylammonium tetrafluoroborate (TBABF 4) as a catalyst for the depolymerization of lignin and its model compound without the addition of oxidants. The impact of electrolytes, reaction times, and solvents on the cleavage of the α-O-4 bond in lignin is investigated. The experimental setup includes specific conditions such as the use of carbon cloth (CC) as the counter electrode and a platinum plate as the working electrode. The TBABF 4 catalyst effectively cleaved the α-O-4 bond in the lignin model molecule with notable selectivity and minimal formation of by-products, resulting in a substantial conversion rate of benzyl phenyl ether (95.7 %) and a high yield of benzaldehyde dimethyl aceta (92.4 %) under specific conditions. This investigation showcases a mild electrochemical catalytic depolymerization approach for lignin model molecules at ambient temperature, thereby presenting novel avenues for further exploration in the field. [Display omitted] • The α-O-4 bond in lignin was effectively cleaved using tetrabutylammonium tetrafluoroborate as an auxiliary electrolyte. [ABSTRACT FROM AUTHOR]

A series of Au nanoparticles decorated nickel tungstate/oxide nanocomplexes with different atom molar ratio of Ni:W were synthesized, and utilized for the electro-oxidation of methanol in alkaline media. [Display omitted] • A series of nickel based catalysts with different Ni:W atom ratio were synthesized. • Catalyst with Ni:W atom ratio of 2:1 exhibits best performance for MOR. • Larger surface area and pore size enhance the electrochemical catalytic efficiency. The methanol oxidation reaction (MOR) serves as a critical determinant of the energy conversion efficiency within direct methanol fuel cells (DMFC). Consequently, the development of cost-effective and efficient electrocatalysts is paramount for enhancing energy conversion efficiency associated with MOR. The nanomaterials with diverse metal atomic molar ratio of (Ni:W) were synthesized via hydrothermal method for the immobilization of Au nanoparticles (Au NPs) onto the sample surface. The crystal structure of nanocomposites was confirmed through X-ray diffraction (XRD), and transmission electron microscopy (TEM) images depicted a specific surface topography. The catalytic performance of the synthesized catalysts in the MOR was assessed through electrochemical analysis. Notably, catalyst with the Ni:W atomic ratio of 2:1, displayed superior electrocatalytic performance when compared to catalysts possessing other different metal ratios. Moreover, chronoamperometry tests conducted over 7200 s and Tafel slope analysis demonstrated the enduring activity and strong resistance to toxicity of the synthesized catalysts. These results highlight the potential of nickel-tungstate bimetallic oxide as an exceptionally efficient catalyst in the field of electrocatalysis. [ABSTRACT FROM AUTHOR]

An electrocatalytic membrane reactor (ECMR) with an anode consisting of Pt nanoparticles (NPs) loaded on a Ti membrane electrode (Pt NPs/Ti) was designed to oxidize cyclohexanone (K) to produce sodium adipate (SA) under mild conditions. The effects of residence time, reaction temperature, current density and initial K concentration on K conversion were investigated. Optimization experiments were conducted to determine the effects of and interactions between different operating parameters on K conversion using a central composite design within the response surface methodology. A 88.3% conversion of K and 99% selectivity to SA were obtained by the ECMR under the optimum conditions of reaction temperature = 30.8 °C, K concentration = 22.54 mmol L−1, residence time = 25 min and current density = 2.07 mA cm−2. The high performance of the ECMR is attributed to electrocatalytic oxidation (at the Pt NPs/Ti electrode), convection-enhanced mass transfer, and the timely removal of the desired products. [ABSTRACT FROM AUTHOR]

We show that a Single-Atom Electrocatalyst (SAC) for the Nitrogen Reduction Reaction (NRR) can provide an environmentally green alternative to the Haber–Bosch high-temperature high-pressure process, replacing the water gas shift production of H2 with H extracted from water. Anchoring the single atom on a two-dimensional substrate provides control to tune NRR catalytic performance toward a SAC possessing high utilization, high activity, and high selectivity. Experimental results suggest that this can significantly improve the activity and selectivity of NRR, but the specific reaction mechanism remains uncertain. This makes it difficult to select new catalytic materials for further optimization. Here we use Density Functional Theory to study the NRR catalytic mechanism on a catalytic model using a MoS2 substrate to support a single atom site. We correct for solvation effects on the electrochemical reactions. We started with Fe@MoS2, for which there are promising experimental reports, and conducted a systematic study of the NRR reaction mechanisms. These results show that N2 adsorption, hydrogenation of N2, desorption of NH3, and Hydrogen Evolution are all critical steps affecting the reaction rates. Based on these steps, we scanned 23 transition metal elements to find improved catalysts. We identified Ir@MoS2 (Mo top site) as the best candidate, predicted to have good catalytic activity and selectivity with 64.11% Faraday Efficiency. These results on the mechanism for NRR and the in silico search for alternative catalysts provide new promising targets for synthesizing novel and efficient SAC@MoS2 NRR catalysts. [ABSTRACT FROM AUTHOR]

We show that a Single-Atom Electrocatalyst (SAC) for the Nitrogen Reduction Reaction (NRR) can provide an environmentally green alternative to the Haber–Bosch high-temperature high-pressure process, replacing the water gas shift production of H2 with H extracted from water. Anchoring the single atom on a two-dimensional substrate provides control to tune NRR catalytic performance toward a SAC possessing high utilization, high activity, and high selectivity. Experimental results suggest that this can significantly improve the activity and selectivity of NRR, but the specific reaction mechanism remains uncertain. This makes it difficult to select new catalytic materials for further optimization. Here we use Density Functional Theory to study the NRR catalytic mechanism on a catalytic model using a MoS2 substrate to support a single atom site. We correct for solvation effects on the electrochemical reactions. We started with Fe@MoS2, for which there are promising experimental reports, and conducted a systematic study of the NRR reaction mechanisms. These results show that N2 adsorption, hydrogenation of N2, desorption of NH3, and Hydrogen Evolution are all critical steps affecting the reaction rates. Based on these steps, we scanned 23 transition metal elements to find improved catalysts. We identified Ir@MoS2 (Mo top site) as the best candidate, predicted to have good catalytic activity and selectivity with 64.11% Faraday Efficiency. These results on the mechanism for NRR and the in silico search for alternative catalysts provide new promising targets for synthesizing novel and efficient SAC@MoS2 NRR catalysts. [ABSTRACT FROM AUTHOR]

Heterogeneous Electron-Fenton (HEF) has been recognized as a prospective solution in tackling refractory organic contaminants. Nevertheless, the low production efficiency of H2O2 and external addition of H2O2 or Fe2+ limit its wide application. In this work, the bi-functional Fe/CeO2 composites were designed to achieve the simultaneous generation of H2O2 and •OH. The electro-catalysis experiments indicate Fe/CeO2 composites present 97% degradation efficiency for 17 mg/L phenol within 0.5 h and it still presented good degradation performance in high salinity condition. The H2O2 yield produced by Fe, CeO2, and Fe/CeO2 revealed that CeO2 and Fe/CeO2 have similar H2O2 productivity about 24 mg/L h−1, suggesting that H2O2 is mainly produced by CeO2. O2-TPD profiles, XPS and Raman spectra indicate that the relative amount of oxygen deficient region (Ov) and chemisorbed oxygen in Fe/CeO2 composites is higher than that in CeO2, which promote the adsorption of O2. Then the effective O2 adsorption can ensure the subsequent electrocatalysis of O2 to H2O2. The impedance measurement shows that Fe/CeO2 composite exhibits excellent conductivity, enabling the transporting of electron. EPR experiments and radical scavenging experiments disclosed that the primary reactive species was •OH, proving the in-situ activation of H2O2 to •OH by Fe/CeO2 composites. This work should offer new insights about the rational design of bi-functional catalyst towards simultaneous generation and activation H2O2 to •OH, thus improving electrocatalytic performance.

Open framework materials (OFMs), such as metal‐organic frameworks and covalent organic frameworks have emerged as promising electrocatalysts to address the global energy crisis and environmental problems. Powdered non‐film forms, that is, bulk OFMs exhibit excellent catalytic activities toward electrocatalytic carbon dioxide reduction, water splitting, and the oxygen reduction reaction. However, electrode preparation using bulk solids suffers from a range of oft‐encountered difficulties, primarily limited by challenges in controlling their thickness, roughness, and particle sizes, despite early performance promises. Targeting energy sustainability, it is a matter of growing interest to directly integrate OFMs in the form of thin films onto conductive substrates. In essence, this leads to electrocatalysts with controlled features: thickness, roughness, and particle sizes. Thus far, there are only a handful of OFM thin films developed for electrocatalysis. Exploration of these understudied OFM thin films to serve electrocatalysis still lies at its infancy. This review will cover the key discoveries of OFM thin films as electrocatalysts and will critically examine the strengths, challenges, and future goals in exploring bespoke OFM thin films for electrocatalysis, under conditions that mimic real‐world applications. [ABSTRACT FROM AUTHOR]

Nitrogen-doped graphdiyne quantum dots (NGDYQDs) have been synthesized hydrothermally from sp-hybridized N-doped graphdiyne and employed to fabricate an electrochemical sensor for the quantification of chloramphenicol (CAP), a typical nitro group-containing antibiotic, in water. The principle of this quantification is based on the high electrocatalytic activity of NGDYQDs to the reduction of −NO2 groups in CAP to hydroxylamine groups. The effects of the electronic structure and size of the quantum dots on electrocatalytic activity were studied experimentally and theoretically. To prepare a sensor for CAP quantification, a suspension of NGDYQDs was prepared, and the NGDYQDs were deposited on a glassy carbon (GC) electrode. The prepared sensor showed a linear response to CAP from 0.1 to 114.5 μM with a limit of detection of approximately 5 nM (at a signal-to-noise ratio of 3) and a sensitivity of approximately 8.79 μA–1 μM–1 cm–2, as well as high repeatability, reproducibility, and stability. Moreover, the sensor has high selectivity and resistance to interference in the presence of other antibiotics (five randomly selected antibiotics: furazolidone, 2-nitroimidazole, amoxicillin, ciprofloxacin, and erythromycin), common biological compounds (glucose, ascorbic acid, and uric acid), common aqueous ions (Na+, K+, Fe3+, Cu2+, Ca2+, Cl–, Br–, CO32–, SO42–, and NO3–), other nitroaromatic compounds (4-nitrophenol and 4-nitroaniline), and common surfactants (sodium dodecyl sulfate and Triton X-100). Furthermore, the sensor was employed to quantify CAP in water samples with high accuracy. Thus, this work provides an electrochemical method for quantifying CAP in real samples with various applications such as biomedical analysis, environmental pollutant detection, and water safety evaluation. [ABSTRACT FROM AUTHOR]

Cu-Ni oxide nanocomposite was synthesized via solvothermal method with nickel (II) nitrate and copper nitrate as Ni and Cu resource respectively. AuNPs/oxide nanocomposite was obtained by dispersing the oxide into the pre-synthesized Au colloid. Transmission electron microscope (TEM) shows that the synthesized oxides are nanoplate morphology. Interplanar distance from the high resolution TEM (HRTEM) image shows that the Ni and Cu in the oxide are multivalent state. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization further proves that the Ni and Cu are multivalent state, and the Au is Au0 form in the nanocomposte. EDS-mapping images confirm large numbers of AuNPs are uniformly absorbed onto the ultra-thin multivalent Cu-Ni oxide nanoplate. The electrochemical properties of multivalent oxide (m-v oxide) with or without AuNPs decoration are investigated in 0.1 M potassium chloride electrolyte with 2.0 mM Ferri/Ferro-Cyanide. When employed for the electrochemical catalysis in methanol oxidation reaction (MOR), the AuNPs/m-v oxide exhibits better electrochemistry performance than m-v oxide. The current density of AuNPs/m-v oxide (21.1 mA/cm2) is 3.4 times bigger than that of m-v oxide/GCE (6.2 mA/cm2). What’s more, it shows good electrochemical stability and lower slope of the Tafel plot (41.87 mV/dec).

Conversion of CO2 into valuable compounds, including fuels, with renewable energy sources and sustainable compounds is a challenge addressed by artificial photosynthesis research. In particular, the application of solar assisted electrochemical (EC) processes, in which electrons are furnished by a photovoltaic (PV) cell, is a promising approach. A PV‐EC system is described, consisting of a CIGS (copper indium gallium selenide) PV unit linked to a carbon electrode loaded with cobalt phthalocyanine as molecular catalyst, able to achieve the CO2 reduction to CO and then to methanol in aqueous media with limited bias voltage. Using CO as starting material, a partial current density of ca. 0.6 mA cm−2 for methanol is obtained at a bias voltage corresponding to a low 240 mV overpotential. Remarkably, the liquid fuel production can be sustained for at least 7 h. Under ideal conditions, the CO2‐to‐CH3OH reaction shows a global Faradaic efficiency of 28 %. [ABSTRACT FROM AUTHOR]

Metal telluride nanocatalysts have been widely used in the catalytic reactions. However, there are few examples of electrocatalytic water oxidation with metal telluride as catalysts, especially Fe‐based telluride, to the best of our knowledge, has not yet been reported. In this work, the Te‐doped Fe‐based catalysts (FeTex) with crystalline and amorphous nanosheet structures have been successfully synthesized by chemical vapor deposition (CVD) as well as electrodeposition (ED) on the iron foam (IF), where the latter exhibited more remarkable electrocatalytic performance towards the oxygen evolution reaction (OER) in the alkaline electrolyte, requiring the overpotential (η) of only 264.4 mV to reach a current density of 10 mA cm−2 with a Tafel slope of 54.2 mV dec−1. The electrochemical study confirmed that the residual Te in ED‐FeTex does play a role in promoting the catalytic activity for the electrocatalytic water oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sm-MOF and NH 2 functionalized Sm-MOF are synthesized by a simple hydrothermal method and characterized by different analytical techniques. • The prepared catalysts are applied for OER and HER. • NH 2 functionalized Sm-MOF exhibits HER/OER performance with overpotential of 20.9/433 mV and Tafel slope of 198/95.1 mV/dec. • Sm-MOF exhibits HER/OER performance with overpotential of 21.6/635 mV and Tafel slope of 38.2/158 mV/dec. • Sm-MOF and NH 2 functionalized Sm-MOF are promising catalysts for renewal energy production via OER and HER. Due to ever-increasing energy demand, development of inexpensive and highly active metal-based materials such as metal–organic framework (MOF) nanoarchitectures for efficient electrocatalytic water splitting via oxygen evolution reactions (OER) and hydrogen evolution reactions (HER) has become a highly challenging task in recent years. Herein, we synthesized two different MOFs by hydrothermal method using 1,4-benzene dicarboxylic acid (1,4-BDC) and 2-amino-1,4-benzenedicarboxylic acid (2-NH 2 -1,4-BDC) as ligands and samarium (Sm) as the metal center. These samarium-based MOF (Sm-MOF) and amine-functionalized samarium-based MOF (NH 2 functionalized Sm-MOF) worked as multifunctional catalysts for OER and HER owing to their attractive rod and hollow spherical morphology with visible pores. Among both, NH 2 functionalized Sm-MOF exhibited significant HER/OER performance with low overpotential of 20.9/433 mV at 10/10 mA/cm2 and a small Tafel slope of 198/95.1 mV/dec in 1 M KOH electrolyte respectively. Moreover, its stability is maintained with 1000 cycles with a minute shift in performance. This strategy shows the novel approach to design a bifunctional electrocatalyst with improved electrochemical surface area (ECSA) of 5650/7425 cm2 for HER/OER and more efficiency for overall electrocatalytic water splitting under alkaline conditions. [ABSTRACT FROM AUTHOR]