Electrochemical Oxidation Reaction Research Articles

Synthesis of 3-sulfonylisoindolin-1-ones from olefinic amides and sodium sulfinates via electrooxidative tandem cyclization.

Sulfonyl groups are motifs that are widely found in biologically active compounds and drug molecules, many isolated natural products as well as pharmaceuticals contain sulfonyl groups. Herein, we present the synthesis of sulfonyl-substituted isoindolones by a electrochemical oxidative radical cascade cycloaddition reaction of olefinic amides with sodium sulfite under oxidant- and catalyst-free conditions. Various olefinic amides and sodium sulfinates were compatible and gave the desired products in yields up to 99%.

Advanced Nanocarbons Toward two-Electron Oxygen Electrode Reactions for H2O2 Production and Integrated Energy Conversion.

Hydrogen peroxide (H2O2) plays a pivotal role in advancing sustainable technologies due to its eco-friendly oxidizing capability. The electrochemical two-electron (2e-) oxygen reduction reaction and water oxidation reaction present an environmentally green method for H2O2 production. Over the past three years, significant progress is made in the field of carbon-based metal-free electrochemical catalysts (C-MFECs) for low-cost and efficient production of H2O2 (H2O2EP). This article offers a focused and comprehensive review of designing C-MFECs for H2O2EP, exploring the construction of dual-doping configurations, heteroatom-defect coupling sites, and strategic dopant positioning to enhance H2O2EP efficiency; innovative structural tuning that improves interfacial reactant concentration and promote the timely release of H2O2; modulation of electrolyte and electrode interfaces to support the 2e- pathways; and the application of C-MFECs in reactors and integrated energy systems. Finally, the current challenges and future directions in this burgeoning field are discussed.

Stable production of hydrogen peroxide over zinc oxide @ zeolitic imidazolate Framework-8 composite catalysts

A promising method of producing hydrogen peroxide (H2O2) is the electrochemical two-electron water oxidation reaction (2e− WOR). In this process, it is important to design electrocatalysts that are both earth abundant and environmentally friendly, as well as offering high stability and production rates. The research of WOR catalysts, such as the extensively used transition metal oxides, is mainly focused on the modification of transition metal elements. Few studies pay attention to the protective heterostructure of metal oxides. Here, we demonstrate for the first time an organometallic skeleton protection strategy to develop highly stable WOR catalysts for H2O2 generation. Unlike the pure ZnO and zeolite imidazole framework-8 (ZIF-8) catalysts, ZnO@ZIF-8 enabled the production of hydrogen peroxide at high voltages. The experimental results demonstrate that the ZnO@ZIF-8 catalyst stably generates H2O2 even under a high voltage of 3.0 V vs. RHE, with a yield reaching 2845.819 μmol/min g−1. ZnO@ZIF-8 shows a relatively low overpotential, with a current density of 10 mA cm−2 and an overpotential of 110 mV. The ZnO@ZIF-8 catalyst’s maximal FE value was 4.72 %. Moreover, the ZnO@ZIF-8 catalyst exhibits remarkable durability even after an extended 60-hour stability test. Operando Raman and theoretic calculation analyses reveal that the metal–organic skeleton being encapsulated on the metal oxide surface synergizes with each other, not only expanding the electrochemical surface area, but also adjusting the catalyst metal sites’ adsorption capacity. A novel approach to the modification of 2e− WOR metal oxide catalyst is presented in this work.

Locally Varying Surface Binding Affinity on Pd-Au Nanocrystals Enhances Electrochemical Ethanol Oxidation Activity.

Noble metal nanocrystals face challenges in effectively catalyzing electrochemical ethanol oxidation reaction (EOR)-represented multistep, multielectron transfer processes due to the linear scaling relationship among binding energies of intermediates, impeding independent optimization of individual elemental steps. Herein, we develop noble metal nanocrystals with a range of local surface binding affinities in close proximity to overcome this challenge. Experimentally, this is demonstrated by applying tensile strain to a Pd surface and decorating it with discrete Au atoms, forming a diversity of binding sites with varying affinities in close proximity for guest molecules, as evidenced by CO probing and density functional theory calculations. Such a surface enables reaction intermediates to migrate between different binding sites as needed for each elemental step, thereby reducing the energy barrier for the overall EOR when compared to reactions at a single site. On these tailored surfaces, we attain specific and mass activities of 32.7 mA cm-2 and 47.8 A mgPd-1 in EOR, surpassing commercial Pd/C by 10.9 and 43.8 times, respectively, and outperforming state-of-the-art Pd-based catalysts. These results highlight the promise of this approach in improving a variety of multistep, multielectron transfer reactions, which are crucial for energy conversion applications.

Energy‐Efficient Co‐production of Benzoquinone and H2 Using Waste Phenol in a Hybrid Alkali/Acid Flow Cell

AbstractIn both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8‐Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8‐Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8‐Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm−2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long‐term stability. The unique configuration of the acid‐base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone.

Energy-Efficient Co-production of Benzoquinone and H2 Using Waste Phenol in a Hybrid Alkali/Acid Flow Cell.

In both the manufacturing and chemical industries, benzoquinone is a crucial chemical product. A perfect and economical method for making benzoquinone is the electrochemical oxidation of phenol, thanks to the traditional thermal catalytic oxidation of phenol process requires high cost, serious pollution and harsh reaction conditions. Here, a unique heterostructure electrocatalyst on nickel foam (NF) consisting of nickel sulfide and nickel oxide (Ni9S8-Ni15O16/NF) was produced, and this catalyst exhibited a low overpotential (1.35 V vs. RHE) and prominent selectivity (99 %) for electrochemical phenol oxidation reaction (EOP). Ni9S8-Ni15O16/NF is beneficial for lowering the reaction energy barrier and boosting reactivity in the EOP process according to density functional theory (DFT) calculations. Additionally, an alkali/acid hybrid flow cell was successfully established by connecting Ni9S8-Ni15O16/NF and commercial RuIr/Ti in series to catalyze phenol oxidation in an alkaline medium and hydrogen evolution in an acid medium, respectively. A cell voltage of only 0.60 V was applied to produce a current density of 10 mA cm-2. Meanwhile, the system continued to operate at 0.90 V for 12 days, showing remarkable long-term stability. The unique configuration of the acid-base hybrid flow cell electrolyzer provides valuable guidance for the efficient and environmentally friendly electrooxidation of phenol to benzoquinone.

Gas Diffusion Electrodes for Electrocatalytic Oxidation of Gaseous Ammonia: Stepping Over the Nitrogen Energy Canyon

As ammonia continues to gain more and more interest as a promising hydrogen carrier compound, so does the electrochemical ammonia oxidation reaction (AmOR). To avoid the liberation of H2 in a reverse Haber‐Bosch reaction under release of the energetically more favorable N2, we propose the oxidation of ammonia to value‐added nitrite (NO2‐), which is usually obtained during the Ostwald process. We investigated the anodic oxidation of gaseous ammonia directly supplied to a gas diffusion electrode (GDE) using a variety of compositionally different multi‐metal catalysts coated on Ni foam under the simultaneous formation of H2 at the cathode. This will double the amount of H2 per ammonia molecule while applying a lower overpotential than that required for water electrolysis (1.4‐1.8 V vs. RHE at 50 mA·cm‐2). A selectivity study demonstrated that some of the catalyst compositions were able to produce significant amounts of NO2‐, and further investigations using the most promising catalyst composition Nif_AlCoCrCuFe integrated within a GDE demonstrated up to 88% Faradaic efficiency for NO2‐ at the anode coupled to close to 100% Faradaic efficiency for the cathodic H2 production.

Unraveling the Mechanism of Ammonia Electrooxidation by Coupled Differential Electrochemical Mass Spectrometry and Surface-Enhanced Infrared Absorption Spectroscopic Studies.

Ammonia electrooxidation has received considerable attention in recent times due to its potential application in direct ammonia fuel cells, ammonia sensors, and denitrification of wastewater. In this work, we used differential electrochemical mass spectrometry (DEMS) coupled with attenuated total reflection-surface-enhanced infrared absorption (ATR-SEIRA) spectroscopy to study adsorbed species and solution products during the electrochemical ammonia oxidation reaction (AOR) on Pt in alkaline media, and to correlate the product distribution with the surface ad-species. Hydrazine electrooxidation, hydroxylamine electrooxidation/reduction, and nitrite electroreduction on Pt have also been studied to enhance the understanding of the AOR mechanism. NH3, NH2, NH, NO, and NO2 ad-species were identified on the Pt surface with ATR-SEIRA spectroscopy, while N2, N2O, and NO were detected with DEMS as products of the AOR. N2 is formed through the coupling of two NH ad-species and then subsequent further dehydrogenation, while the dimerization of HNOad leads to the formation of N2O. The NH-NH coupling is the rate-determining step (rds) at high potentials, while the first dehydrogenation step is the rds at low potentials. These new spectroscopic results about the AOR and insights could advance the search and design of more effective AOR catalysts.

Electrocatalytic Glycerol Conversion: A Low-Voltage Pathway to Efficient Carbon-Negative Green Hydrogen and Value-Added Chemical Production.

Electrochemical glycerol oxidation reaction (GLYOR) could be a promising way to use the abundantly available glycerol for production of value-added chemicals and fuels. Completely avoiding the oxygen evolution reaction (OER) with GLYOR is an evolving strategy to reduce the overall cell potential and generate value-added chemicals and fuels on both the anode and cathode. We demonstrate the morphology-controlled palladium nanocrystals, afforded by colloidal chemistry, and their established morphology-dependent GLYOR performance. Although it is known that controlling the morphology of an electrocatalyst can modulate the activity and selectivity of the products, still it is a relatively underexplored area for many reactions, including GLYOR. Among nanocube (Pd-NC), truncated octahedron (Pd-TO), spherical and polycrystalline (Pd-PC) morphologies, the Pd-NC electrocatalyst deposited on a Ni foam exhibits the highest glycerol conversion (85%) along with 42% glyceric acid selectivity at a low applied potential of 0.6 V (vs reversible hydrogen electrode (RHE)) in 0.1 M glycerol and 1 M KOH at ambient temperature. Owing to the much favorable thermodynamics of GLYOR on the Pd-NC surface, the assembled electrolyzer requires an electricity input of only ∼3.7 kWh/m3 of H2 at a current density of 100 mA/cm2, in contrast to the requirement of ≥5 kWh/m3 of H2 with an alkaline/PEM electrolyzer. Sustainability has been successfully demonstrated at 10 and 50 mA/cm2 and up to 120 h with GLYOR in water and simulated seawater.

Integrated Electrolytic Hydrogen Production for Boosting Energy Utilization

AbstractElectrocatalytic water splitting, powered by clean energy sources, represents a sustainable method for hydrogen (H2) production. Although extensive research has concentrated on performance indicators like current density and faradaic efficiency, the widespread adoption of electrocatalytic water splitting encounters challenges primarily due to high cell voltages and electricity costs. These issues stem from the sluggish kinetics of the anodic oxygen evolution reaction (OER). Various efforts to replace sluggish OER with thermodynamically more favorable anodic reactions have been demonstrated as pathbreaking strategies for energy‐efficient H2 evolution. In this concept, we aim to comprehensively explore alternative electrochemical oxidation reactions combined with H2 evolution and propose insights for the future development of cost‐effective integrated electrolysis for H2 production.

Electrosynthesis of nitrate by FeS2-TiO2 heterogeneous nanoparticles supported on 2-methylimidazolium functionalized polypyrrole/graphene oxide

Electrochemical nitrogen oxidation reaction (NOR) acts as a clean and sustainable approach for promisingly replacing the conventional industrial method for producing nitrate. Designing and preparing the effective electrocatalysts for NOR has aroused great research interests. Herein, FeS2-TiO2 heterostructures are well-dispersed on the surface of 2-methylimidazolium functionalized polypyrrole/graphene oxide (2-MeIm/PPy/GO) by the in situ growth due to the ion-exchange and the coordination between the 2-MeIm groups and the metal precursors, which exhibit the excellent NOR electroactivity. The highest NO3– yield by the obtained FeS2-TiO2@2-MeIm/PPy/GO reaches to 137.04 μg h−1 mg-1act. with the maximum Faradic efficiency (FE) of 4.38 % at 2.04 V (vs. RHE), better than most reported electrocatalysts. The good selectivity for producing nitrate is also achieved, but the stability of both the NO3– yield and FE present a trend of rising and then declining in the cyclic test of FeS2-TiO2@2-MeIm/PPy/GO. The irreversible conversion of the electrocatalysts can be confirmed through detailed characterization towards the crystal structures and chemical states of FeS2-TiO2@2-MeIm/PPy/GO after long term NOR test. The electrochemical step of NOR mainly occurs at FeS2, converting the inert N2 to active *NO intermediates. SO42- generated at high NOR potential gradually increase by the oxidation of S element, which can cause the promotion of the NOR performance before the fourth cycle. But along with the disappearance of FeS2 phase, FeS2-TiO2 as the catalytic center is finally irreversibly converted to Fe and S ions doped TiO2, resulting in the sharp drop of both the NO3– yield and FE at the sixth cycle. This work will provide valuable guidance for the designing and preparing NOR electrocatalysts.

Enhancing hydrogen production capability from urine-containing sewage through optimization of urea oxidation pathways

The electrochemical urea oxidation reaction (UOR) represents a promising route to sustainable hydrogen production and reuse of urea-containing sewage. However, the efficiency of UOR is hindered by the dehydrogenation of intermediate *CONH2NH and the conversion of toxic intermediate the *CO. Herein, we report a robust strategy to elevate UOR performance by introducing iron (Fe) atoms into the Ni3S2@NiSe2 heterojunctions (denoted Fe-Ni3S2@NiSe2). The Fe-Ni3S2@NiSe2 exhibits remarkable selectivity and electrocatalytic activity towards UOR, attributed to its reconstruction into Fe-NiOOH species during UOR process, as confirmed by in-situ Raman technology. Utilizing Fe-Ni3S2@NiSe2 as both the cathode and anode in a single-chamber electrolytic cell, the hydrogen production rate reaches 588.4 μmol h−1 in simulated urea-containing sewage and 432.1 μmol h−1 in actual human urine, respectively. Notably, in both scenarios, no oxygen product is detected, and the hydrogen production efficiency surpasses that of traditional water splitting by 5.8-fold and 4.3-fold, respectively. In-situ infrared spectroscopy study reveals that the UOR process involves the cleavage of C-N bond and the generation of CO2. Density functional theory calculations further signifies that the incorporation of Fe facilitates the dehydrogenation of *CONH2NH intermediates, strengthens the d-p hybridization, and weakens O-H bonds, thereby resulting in reduced energy barriers for UOR. Our strategy holds promise for efficient hydrogen production from sewage via UOR, offering potential implications for wastewater treatment and clean energy generation.

Novel Fe-Ti nanoparticles synthesized in deep eutectic solvents for enhanced photo-electro-Fenton processes: Synergistic effects and environmental applications

An innovative titanium-magnetite (Fe-Ti) catalyst was developed using a production strategy based on water-free solvents such as deep eutectic solvents (DES) for the removal of persistent pollutants. The prepared catalyst was applied in electro-Fenton and photo-electro-Fenton processes. To this end, a new cell design with electrodes based on conductive materials was developed using 3D printing in two different electrochemical cells configurations: vertical electrode configuration (VEC) and horizontal electrode configuration (HEC). The HEC showed good performance attaining a yield hydrogen peroxide production of 20 mg·L−1 and being able to operate in electro-Fenton degradation batch assays for the removal of the drugs (Antipyrine and Lissamine Green B). Then, the heterogeneous bimetallic catalyst (BC-FeTi) was tested and compared with the monometallic Fe catalyst (MC-Fe). The results with both catalysts showed a synergistic effect combining electrochemical oxidation and Fenton reaction, promoting the best removal of the target pollutants. Subsequently, the contribution of UV radiation was evaluated with BC-FeTi, achieving that more than 80 % of both pollutants were removed in 80 min by the photo-Fenton process, confirming the high affinity of oxidizing free radicals for high molecular weight organic molecules. Finally, the simultaneous application of electro- and photo-oxidation (photo-electro-Fenton) significantly improved the removal of the target contaminants from the aqueous solution, achieving complete removal in 50 and 80 min for Lissamine Green B and Antipyrine, respectively. The stability and reusability of BC-FeTi and 3D-printed electrodes were achieved in five successive working cycles, with negligible loss of activity compared to new catalysts, which achieved greater than 99 % removal after five consecutive runs. Leaching of iron and titanium from the catalyst evaluated throughout the cycles, was low, totalling 2.7 and 4.5 % at the end of the fifth cycle.

Molecularly imprinted ratiometric electrochemical sensor based on 3D-1D MoS2@CNTs hetero-nanoflower for selective detection of trimethoprim

Trimethoprim (TMP) is a broad-spectrum antibiotic that is frequently found residue in the environment and food. An innovative electrochemical sensor was proposed for the detection of trimethoprim with high selectivity, sensitivity and reproducibility through the integration of the flower-like MoS2@CNTs heterostructure as substrate, molecular imprinted polymer (MIP) technology as recognition, and the ratiometric strategy between trimethoprim and ferrocene (Fc) for quantitative. The recognition reaction of TMP by MIP-MoS2@CNTs sensor was assumed as an irreversible electrochemical oxidation reaction controlled by a combination of adsorption-diffusion process with two electrons and protons. With the incorporation of Fc during detection, a satisfying linear relationship of ITMP/IFc and the concentration of TMP was achieved, indicating a detection concentration ranging from 50 to 3000 nmol·L−1 with a detection limit of 27.01 nmol·L−1. In addition, the MoS2@CNTs MIP ratiometric sensor exhibited good stability for 20 days and excellent reproducibility with a relative standard deviation of 1.06 %, which was lower than 3.89 % of single signal. The practical feasibility of the sensor was detected in water samples with recovery rates of 98.62 ∼ 107.47 % and fish samples with recovery rates of 98.93 ∼ 105.45 %. Overall, the developed MIP ratiometric sensor provides a versatile system with easy operation and great potential for detecting small hazardous molecules in the environment and food products.

Deciphering the Role of Nickel in Electrochemical Organic Oxidation Reactions

AbstractOrganic oxidation reactions (OORs) powered by renewable energy sources are gaining importance as a favorable alternative to oxygen evolution reaction, with the promise of reducing the cell potential and enhancing the overall viability of the water electrolysis. This comprehensive review delves into the electrochemical oxidation of diverse organic compounds, including alcohols, aldehydes, amines, and urea, as well as biomass‐derived renewable feedstocks such as hydroxymethylfurfural and glycerol. The key focus centers on the role of nickel (Ni)‐based catalysts for these OORs. The unique redox activity and chemical nature of Ni have been proven instrumental for the sustainable and cost‐effective oxidation of various organic molecules more efficiently and selectively. This review article discusses how strategic choices, such as the selection of foreign metals, intercalating species, vacancies, defects, and a secondary element (e.g. chalcogens and non‐metals), contribute to tuning the electrochemical performances of a Ni‐based (pre)catalyst for OORs. Moreover, this review provides insights into the active species in various reaction environments and further explores reaction mechanisms, to apparent phase changes of the catalyst with the most relevant examples. Finally, the review not only elucidates the limitations of the current approaches but also outlines potential avenues for future advancements in OOR.

Amorphous electrocatalysts for urea oxidation reaction

Electrochemical urea oxidation reaction (UOR) is a promising alternative to oxygen evolution reaction (OER) for realizing energy-saving hydrogen production. Developing efficient electrocatalysts for UOR becomes a central challenge. Recently, amorphous materials have been extensively used as UOR catalysts because of their numerous defective sites and flexible electronic properties. In this review, recent advancements in the development of amorphous UOR electrocatalysts are analyzed. The UOR mechanism is discussed, and the design of amorphous catalysts is then analyzed. The main catalyst design strategies are illustrated, including nanostructure control, heteroatom doping, composition regulation, and heterostructure construction. Also, electrocatalysts’ structure-performance correlation is interpreted. Perspectives in this field are proposed for guiding future studies on the development of high-performance amorphous catalysts towards energy sustainability.

Electrochemical hydrogenation and oxidation of organic species involving water.

Fossil fuel-driven thermochemical hydrogenation and oxidation using high-pressure H2 and O2 are still popular but energy-intensive CO2-emitting processes. At present, developing renewable energy-powered electrochemical technologies, especially those using clean, safe and easy-to-handle reducing agents and oxidants for organic hydrogenation and oxidation reactions, is urgently needed. Water is an ideal carrier of hydrogen and oxygen. Electrochemistry provides a powerful route to drive water splitting under ambient conditions. Thus, electrochemical hydrogenation and oxidation transformations involving water as the hydrogen source and oxidant, respectively, have been developed to be mild and efficient tools to synthesize organic hydrogenated and oxidized products. In this Review, we highlight the advances in water-participating electrochemical hydrogenation and oxidation reactions of representative organic molecules. Typical electrode materials, performance metrics and key characterization techniques are firstly introduced. General electrocatalyst design principles and controlling the microenvironment for promoting hydrogenation and oxygenation reactionsinvolving waterare summarized. Furthermore, paired hydrogenation and oxidation reactions are briefly introduced before finally discussing the challenges and future opportunities of this research field.

Nickel Hydroxide-Based Electrocatalysts for Promising Electrochemical Oxidation Reactions: Beyond Water Oxidation.

Transition metal hydroxides have attracted significant research interest for their energy storage and conversion technique applications. In particular, nickel hydroxide (Ni(OH)2 ), with increasing significance, is extensively used in material science and engineering. The past decades have witnessed the flourishing of Ni(OH)2 -based materials as efficient electrocatalysts for water oxidation, which is a critical catalytic reaction for sustainable technologies, such as water electrolysis, fuel cells, CO2 reduction, and metal-air batteries. Coupling the electrochemical oxidation of small molecules to replace water oxidation at the anode is confirmed as an effective and promising strategy for realizing the energy-saving production. The physicochemical properties of Ni(OH)2 related to conventional water oxidation are first presented in this review. Then, recent progress based on Ni(OH)2 materials for these promising electrochemical reactions is symmetrically categorized and reviewed. Significant emphasis is placed on establishing the structure-activity relationship and disclosing the reaction mechanism. Emerging material design strategies for novel electrocatalysts are also highlighted. Finally, the existing challenges and future research directions are presented.

Molybdenum, tungsten doped cobalt phosphides as efficient catalysts for coproduction of hydrogen and formate by glycerol electrolysis

H2 and formate are important energy carriers in fuel-cells and feedstocks in chemical industry. The hydrogen evolution reaction (HER) coupling with electro-oxidative cleavage of thermodynamically favorable polyols is a promising way to coproduce H2 and formate via electrochemical means, highly active catalysts for HER and electrooxidative cleavage of polycols are the key to achieve such a goal. Herein, molybdenum (Mo), tungsten (W) doped cobalt phosphides (Co2P) deposited onto nickel foam (NF) substrate, denoted as Mo-Co2P/NF and W-Co2P/NF, respectively, were investigated as catalytic electrodes for HER and electrochemical glycerol oxidation reaction (GOR) to yield H2 and formate. The W-Co2P/NF electrode exhibited low overpotential (η) of 113 mV to attain a current density (J) of −100 mA cm−2 for HER, while the Mo-Co2P/NF electrode demonstrated high GOR efficiency for selective production of formate. In situ Raman and infrared spectroscopic characterizations revealed that the evolved CoO2 from Co2P is the genuine catalytic sites for GOR. The asymmetric electrolyzer based on W-Co2P/NF cathode and Mo-Co2P/NF anode delivered a J = 100 mA cm−2 at 1.8 V voltage for glycerol electrolysis, which led to 18.2 % reduced electricity consumption relative to water electrolysis. This work highlights the potential of heteroelement doped phosphide in catalytic performances for HER and GOR, and opens up new avenue to coproduce more widespread commodity chemicals via gentle and sustainable electrocatalytic means.

Rational coupling of selective electrochemical oxidation and reduction reactions for in-situ value-added chemical generation

In this review, the recent developments achieved in the electrochemical production of Bi-value-added chemicals by replacing the conventional (oxygen evolution reaction) OER and (hydrogen evolution reaction) HER with thermodynamically favorable reactions are summarized. Beyond conventional electrolysis used for the generation of a single value-added product at the anode or cathode, hybrid electrolysis opens a new avenue for the simultaneous production of value-added concurrently at the anode and cathode. This new strategy can not only increase the efficiency of value-added products, but also abolish the generation of explosive gaseous products by eliminating conventional OER and HER. To construct a hybrid electrolyzer, various anodic oxidation reactions including the oxidation of glucose, glycerol, CH4, 1,2-propanediol, 1-phenylethanol, isopropanol, benzyl alcohol, biomass-derived HMF, syringaldehyde, and o-phenylenediamine are used to replace the anodic OER, whereas CO2RR is mostly used to replace the cathodic HER. Furthermore, the collective efforts of the electrocatalyst, device architecture, and fabrication method toward selective product formation are explained in detail.