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In this work, we use a Bayesian optimization (BO) algorithm to sample the space of covalent organic framework (COF) components aimed at the design of COFs with a high hole conductivity. COFs are crystalline, often porous coordination polymers, where organic molecular units—called building blocks (BBs)—are connected by covalent bonds. Even though we limit ourselves here to a space of three-fold symmetric BBs forming two-dimensional COF sheets, their design space is still much too large to be sampled by traditional means through evaluating the properties of each element in this space from first principles. In order to ensure valid BBs, we use a molecular generation algorithm that, by construction, leads to rigid three-fold symmetric molecules. The BO approach then trains two distinct surrogate models for two conductivity properties, level alignment vs a reference electrode and reorganization free energy, which are combined in a fitness function as the objective that evaluates BBs' conductivities. These continuously improving surrogates allow the prediction of a material's properties at a low computational cost. It thus allows us to select promising candidates which, together with candidates that are very different from the molecules already sampled, form the updated training sets of the surrogate models. In the course of 20 such training steps, we find a number of promising candidates, some being only variations on already known motifs and others being completely novel. Finally, we subject the six best such candidates to a computational reverse synthesis analysis to gauge their real-world synthesizability. [ABSTRACT FROM AUTHOR]

We report the free energy barriers for the elementary reactions in the 2e− and 4e− oxygen reduction reaction (ORR) steps on Au(100) in an alkaline solution. Due to the weak adsorption energy of O2 on Au(100), the barrier for the association channel is very low, and the 2e− pathway is clearly favored, while the barrier for the O–O dissociation channel is significantly higher at 0.5 eV. Above 0.7 V reversible hydrogen electrode (RHE), the association channel becomes thermodynamically unfavorable, which opens up the O–O dissociation channel, leading to the 4e− pathway. The low adsorption energy of oxygenated species on Au is now an advantage, and residue ORR current can be observed up to the 1.0–1.2 V region (RHE). In contrast, the O–O dissociation barrier on Au(111) is significantly higher, at close to 0.9 eV, due to coupling with surface reorganization, which explains the lower ORR activity on Au(111) than that on Au(100). In combination with the previously suggested outer sphere electron transfer to O2 for its initial adsorption, these results provide a consistent explanation for the features in the experimentally measured polarization curve for the alkaline ORR on Au(100) and demonstrate an ORR mechanism distinct from that on Pt(111). It also highlights the importance to consider the spin state of O2 in ORR and to understand the activation barriers, in addition to the adsorption energies, to account for the features observed in electrochemical measurements. [ABSTRACT FROM AUTHOR]

The development of water electrolysis catalysts that accelerate the oxygen evolution reaction (OER) is a crucial challenge. Ni-based oxides are promising OER catalysts; however, quantitative studies of Ni-based oxides remain unexplored. In this study, we quantitatively evaluated the OER activity of LiNi0.5Mn1.5O4 as a thin-film electrode catalyst. The LiNi0.5Mn1.5O4 thin film fabricated using a sputtering method exhibited a current density of 6.6 and ∼2.6 mAcm−2 for geometric and estimated areas, respectively, at 1.78 V vs. a reversible hydrogen electrode. X-ray photoelectron spectroscopy indicated the presence of Ni3+ in the as-grown and post-OER LiNi0.5Mn1.5O4 thin films. These results suggest that Ni3+ plays a key role in the OER of LiNi0.5Mn1.5O4. [ABSTRACT FROM AUTHOR]

We have developed and implemented an implicit electrolyte model in the Vienna Ab initio Simulation Package (VASP) that includes nonlinear dielectric and ionic responses as well as a nonlocal definition of the cavities defining the spatial regions where these responses can occur. The implementation into the existing VASPsol code is numerically efficient and exhibits robust convergence, requiring computational effort only slightly higher than the original linear polarizable continuum model. The nonlinear + nonlocal model is able to reproduce the characteristic "double hump" shape observed experimentally for the differential capacitance of an electrified metal interface while preventing "leakage" of the electrolyte into regions of space too small to contain a single water molecule or solvated ion. The model also gives a reasonable prediction of molecular solvation free energies as well as the self-ionization free energy of water and the absolute electron chemical potential of the standard hydrogen electrode. All of this, combined with the additional ability to run constant potential density functional theory calculations, should enable the routine computation of activation barriers for electrocatalytic processes. [ABSTRACT FROM AUTHOR]

The computational modeling of electrochemical interfaces and their applications in electrocatalysis has attracted great attention in recent years. While tremendous progress has been made in this area, however, the accurate atomistic descriptions at the electrode/electrolyte interfaces remain a great challenge. The Computational Hydrogen Electrode (CHE) method and continuum modeling of the solvent and electrolyte interactions form the basis for most of these methodological developments. Several posterior corrections have been added to the CHE method to improve its accuracy and widen its applications. The most recently developed grand canonical potential approaches with the embedded diffuse layer models have shown considerable improvement in defining interfacial interactions at electrode/electrolyte interfaces over the state-of-the-art computational models for electrocatalysis. In this Review, we present an overview of these different computational models developed over the years to quantitatively probe the thermodynamics and kinetics of electrochemical reactions in the presence of an electrified catalyst surface under various electrochemical environments. We begin our discussion by giving a brief picture of the different continuum solvation approaches, implemented within the ab initio method to effectively model the solvent and electrolyte interactions. Next, we present the thermodynamic and kinetic modeling approaches to determine the activity and stability of the electrocatalysts. A few applications to these approaches are also discussed. We conclude by giving an outlook on the different machine learning models that have been integrated with the thermodynamic approaches to improve their efficiency and widen their applicability. [ABSTRACT FROM AUTHOR]

This work vividly demonstrates the rational design of VSe 2-x O x -SS cathode as an effective strategy to achieve fast and highly aqueous zinc ion storage. [Display omitted] • A simple and fast surface oxygen implantation strategy was designed to adjust the electronic structure of VSe 2 and form a surface protective film. • The VSe 2-x O x -SS-30 electrode showed higher specific capacity, better rate performance and more satisfactory cycling stability. • The zinc (de)intercalation and transformation reactions mechanism was revealed by some ex-situ/in-situ techniques. Interfacial chemical modification is an effective strategy to adjust the strong Coulombic ion-lattice interactions with high valence cations experienced by electrode materials, facilitating the reaction kinetic. In this paper, a simple and fast surface oxygen implantation strategy was designed to adjust the electronic structure of stainless steel (SS) supported vanadium diselenide (VSe 2) nanosheets and form a surface protective film, which effectively accelerates the reaction kinetics of Zn2+ and extends the cycle life of the battery. It is demonstrated that the conductivity, pseudocapacitance and specific capacity can be tuned by selectively introducing oxygen species to the surface, which provides an important reference for the design of electrodes with controlled surface chemistry. Density functional theory (DFT) calculations also confirm that the electronic structure can be adjusted by surface oxygen injection strategy, which not only improves the conductivity, but also adjusts the adsorption energy, thus providing favorable conditions for zinc ion storage. Benefiting from the selenium vacancies and pores generated by the removal of part of selenium, and the oxide film formed on the surfaces, the VSe 2-x O x -SS-30 electrode showed higher specific capacity (188.4 mAh/g at 0.5 A g−1 after 50 cycles), better rate performance (107.1 mAh/g at 4 A g−1) and more satisfactory cycling stability (83.1 mAh/g at 5 A g−1 after 1800 cycles) than VSe 2 -SS electrode. Importantly, the flexible quasi-solid-state VSe 2-x O x -SS-30//Zn battery also exhibits high specific capacity and excellent environmental adaptability. Furthermore, the zinc (de)intercalation and transformation reactions mechanism was revealed by some ex-situ/in-situ techniques. [ABSTRACT FROM AUTHOR]

[Display omitted] Photoelectrochemical (PEC) water splitting on semiconductor electrodes is considered to be one of the important ways to produce clean and sustainable hydrogen fuel, which is a great help in solving energy and environmental problems. Bismuth vanadate (BiVO 4) as a promising photoanode for photoelectrochemical water splitting still suffers from poor charge separation efficiency and photo-induced self-corrosion. Herein, we develop heterojunction-rich photoanodes composed of BiVO 4 and iron vanadate (FeVO 4), coated with nickel iron oxide (NiFeO x /FeVO 4 /BiVO 4). The formation of the interface between BiVO 4 and FeVO 4 (Bi-VO 4 -Fe bridges) enhances the interfacial interaction, resulting in improved performance. Meanwhile, high-conductivity FeVO 4 and NiFeO x oxygen evolution co-catalysts effectively enhance bulk electron/hole separation, interface water's kinetics and photostability. Concurrently, the optimized NiFeO x /FeVO 4 /BiVO 4 possesses a remarkable photocurrent density of 5.59 mA/cm2 at 1.23 V versus reversible hydrogen electrode (vs RHE) under AM 1.5G (Air Mass 1.5 Global) simulated sunlight, accompanied by superior stability without any decreased of its photocurrent density after 14 h. This work not only reveals the crucial role of built-in electric field in BiVO 4 -based photoanode during PEC water splitting, but also provides a new guide to the design of efficient photoanode for PEC. [ABSTRACT FROM AUTHOR]

Symmetric solid oxide fuel cells (SSOFCs) are attracting much attention due to their ability to improve chemical and thermal compatibility between electrolytes and electrodes and reduce manufacturing costs. The in-situ precipitating of electrode in reduction atmosphere has been proved to be an effective strategy to improve the maximum power density of SSOFCs. Herein, we use the Li(Ni x Co 2/3-x Mn 1/3)O 2 (LNCM) serial material as the symmetrical electrodes to fabricate SSOFCs, which are operated in normal and reverse mode. In reverse operation, the LNCM is firstly reduced by hydrogen and in-situ precipitates the Ni–Co alloy and Li 2 MnO 3. The electrochemical impedance spectra (EIS) indicates that the reduced product delivers excellent oxygen reducing activity as well as promising catalytic activity toward hydrogen oxidation reaction. Thus, the SSOFCs based on LNCM symmetric electrodes present superior electrochemical performance in the reverse operation. Moreover, in the LNCM serial samples, the atomic ratio of Ni and Co at the B site is adjusted to control the contents of in-situ precipitation for further optimizing the cell performance. Using Li[Ni 1/2 Co 1/6 Mn 1/3 ]O 2 as symmetric electrodes shows outstanding performance of 923 mW cm−2 at 550 °C. This work provides a reference scheme for electrode design of SSOFCs. [ABSTRACT FROM AUTHOR]

Making green hydrogen from natural biomass glucose electrolysis represents a successful win-win scenario which not only achieves energy-efficient hydrogen production but also yields high-value-added chemicals. Herein, we report a NiFe-PBA catalyst synthesized by a facile co-precipitation method for glucose electrooxidation reaction (GOR). Benefiting from the unique ligand structure and the optimal electron, the Ni 1·6 Fe-PBA achieves a current density of 50 mA cm⁻2 at a potential of only 1.42 V versus Reversible Hydrogen Electrode (RHE), and it maintains potential stability for 50 h. Through an intermittent multipotential-step method it was known that NiOOH is the active site of GOR. Based on the superior GOR activity of this catalyst, we constructed a two-electrode glucose electrolysis hydrogen making system. At a current density of 50 mA cm⁻2, this system reduced the voltage of 230 mV compared to traditional water electrolysis. This improvement significantly reduces energy consumption, requiring only 43.4 kWh to produce 1 kg of H 2 , saving 6.1 kWh of energy power. To our excitement, we analyzed the electrolyte after stability measurement and found the production of GRA, an important platform molecule for chemical industry and medical treatment. This research provides a promising and sustainable approach for efficient hydrogen production and the value-up of biomass feed-stock. [Display omitted] • NiFe-PBA was synthesized using a simple and economical room-temperature co-precipitation method. • By adjusting the Ni/Fe molar ratio, the electronic environment of Ni was tuned, maximizing the stabilization energy. • The Ni 1·6 Fe-PBA‖Pt/C device requires only 43.4 kWh to produce 1 kg of H 2 under a current density of 50 mA cm−2 and produces GRA in anode. [ABSTRACT FROM AUTHOR]

This study reports a unique flow-through electrode design for hydrogen production in alkaline water electrolysis. This paper investigates a variety of electrodeposition coatings on the 3D-printed electrodes, including nickel, nickel-copper, and nickel-iron. The catalytic activity and properties of the electrodes are examined through electrochemical measurements involving linear sweep voltammetry, cyclic voltammetry, electrochemical impedance spectroscopy, and surface morphology analysis. An experimental setup is also developed to measure hydrogen production and evaluate the efficiency of the designed electrodes. The study finds the flow-through electrodes coated with nickel-copper and nickel-iron achieve the current densities of 54 mA/cm2 and 45 mA/cm2, respectively. The activation overpotentials for the nickel-copper coated electrode are reported as 539 mV, and 408 mV for the nickel-iron coated electrode, both at a current density of 10 mA/cm2. The highest production rate is obtained within the first 15 minutes, 0.273 μg/s for the Ni-Cu flow-through electrode and 0.255 μg/s for the Ni-Fe flow-through electrode. The study further shows that flow-through electrodes produce hydrogen with an efficiency approximately 74% higher than traditional electrodes, suggesting a potentially better design for better hydrogen production in industrial applications. • This study reports a new flow-through electrode design for hydrogen production. • The electrodes are fabricated using 3D-printing and coated using electrodeposition. • The performance is evaluated using electrochemical and hydrogen measurements. • The study finds that flow-through electrodes perform better than traditional. • The flow-through electrodes consume less energy with the same or higher production. [ABSTRACT FROM AUTHOR]

[Display omitted] The acidic CO 2 reduction reaction (CO 2 RR) offers a promising approach to mitigate CO 2 reactant loss and carbonate deposition, which are challenging issues in alkaline or neutral electrolytes. However, the hydrogen evolution reaction (HER) competes in the proton-rich environment near the catalyst surface as a side reaction, reducing the energy efficiency of generating multi-carbon (C 2+) products. In this work, we proposed a palladium (Pd) doping strategy in a copper (Cu)-based catalyst to stabilize polarized Cu0-Cu+ sites, thus enhancing the C C coupling step during the CO 2 RR while suppressing HER. At an optimal doping ratio of 6%, the Pd dopants were well dispersed as single atoms without aggregation, allowing for the stabilization of subsurface oxygen (O Sub), preserving the polarized Cu0-Cu+ active sites, and reducing the energy barrier of C C coupling. The Pd-doped Cu/Cu 2 O catalyst exhibited a peak Faradaic efficiency (FE) of 64.0% for C 2+ products with a corresponding C 2+ partial current density of 407.1 mA∙cm−2 at −2.18 V versus a reversible hydrogen electrode, a high CO 2 single-pass conversion efficiency (SPCE) of 73.2%, as well as a high electrochemical stability of ∼ 150 h at industrially relevant current densities, thus suggesting a potential approach for tuning the electrocatalytic CO 2 performances in acidic environments with higher carbon conversion efficiencies. [ABSTRACT FROM AUTHOR]

Silver-based catalytic materials have garnered considerable attention due to their high selectivity towards carbon monoxide (CO) in the electrochemical reduction (ECR) of CO2. However, the fabrication of silver-based ECR catalysts with high product selectivity and low competitive reaction activity using facile methods remains challenging. This study employed in situ electrochemical reconstruction to design high-performance silver-based catalytic materials for ECR, exploring performance enhancement mechanisms. Low-temperature electrochemical reconstruction was used to prepare silver-based catalysts, and the effects of metal ion chelating agents including ethylenediaminetetraacetic acid, citric acid, and sodium citrate were also investigated. Results showed that Ag-SC, namely the catalysts fabricated with sodium citrate as chelating agent, exhibited highly selective CO production, with faradaic efficiency of 93.23% at −0.85 V (versus reversible hydrogen electrode, RHE) and CO partial current density of −7.92 mA cm−2. Electrochemical impedance analysis confirmed low electron transfer resistance of Ag-SC, with 14.54 Ω, indicating superior electron transfer capability, and high ECR activity. Ag-SC also demonstrated excellent hydrophobicity, suppressing the competitive hydrogen evolution reaction and enhancing CO selectivity. In situ electrochemical reconstruction thus offers a simple, low-cost method for preparing silver-based catalysts tailored for ECR, with practical implications for electrode fabrication and catalytic material design. [ABSTRACT FROM AUTHOR]

Efficcient elecctro-oxidation of 5-hydroxymethylfurfural (HMF) to produce 2,5-furandicarboxylic acid (FDCA) was achieved in a low-concentrated alkaline electrolyte over a single-atom-ruthenium supported on Co 3 O 4 (Ru 1 -Co 3 O 4). Single-atom-Ru enhances hydroxyl (OH–) adsorption, thereby improving the oxidation of HMF. The design for the Ru 1 -Co 3 O 4 catalyst enables efficient HMF-to-FDCA electrocatalysis without using strong alkaline electrolytes, which may greatly improve the profitability of HMF-to-FDCA electroccatalysis. [Display omitted] Electrocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), a sustainable strategy to produce bio-based plastic monomer, is always conducted in a high-concentration alkaline solution (1.0 mol L−1 KOH) for high activity. However, such high concentration of alkali poses challenges including HMF degradation and high operation costs associated with product separation. Herein, we report a single-atom-ruthenium supported on Co 3 O 4 (Ru 1 -Co 3 O 4) as a catalyst that works efficiently in a low-concentration alkaline electrolyte (0.1 mol L−1 KOH), exhibiting a low potential of 1.191 V versus a reversible hydrogen electrode to achieve 10 mA cm−2 in 0.1 mol L−1 KOH, which outperforms previous catalysts. Electrochemical studies demonstrate that single-atom-Ru significantly enhances hydroxyl (OH−) adsorption with insufficient OH− supply, thus improving HMF oxidation. To showcase the potential of Ru 1 -Co 3 O 4 catalyst, we demonstrate its high efficiency in a flow reactor under industrially relevant conditions. Eventually, techno-economic analysis shows that substitution of the conventional 1.0 mol L−1 KOH with 0.1 mol L−1 KOH electrolyte may significantly reduce the minimum selling price of FDCA by 21.0%. This work demonstrates an efficient catalyst design for electrooxidation of biomass working without using strong alkaline electrolyte that may contribute to more economic biomass electro-valorization. [ABSTRACT FROM AUTHOR]

This article presents a comparative study of the production of hydrogen by the electrolysis of water using two forms of electrodes; cylindrical and flat. The objective of this comparison is to select the best type of electrolyzer to produce hydrogen for the same volume of water and the same operating voltage. An analytical study and experimental tests were carried out on a cylindrical electrolyser consisting of two concentric cylindrical electrodes separated by a variable thickness e (3.5 mm, 4 mm, 5.5 mm, 8.5 mm and 9 mm), then a flat electrolyser consisting of two flat electrodes spaced by a distance d (2 mm, 4 mm, 6 mm, 10 mm and 15 mm). For each cylindrical electrolyser there corresponds a single electrolyser with flat electrodes. The preliminary study revealed that the production of hydrogen in an electrolyzer is significantly affected by the distance separating the two electrodes and their shapes. Indeed, the comparative electrolysis results show that in each case the electrolyzer with cylindrical electrodes clearly prevails over its counterpart with flat electrodes for the same operating conditions and for the same quantity of water injected into the electrolysis. • The technique used to produce hydrogen is water electrolysis. • The production of hydrogen in an electrolyzer is significantly affected by the distance separating the two electrodes. • The production of hydrogen in an electrolyzer depends on the shapes of the electrodes (cylindrical or flat). • An electrolyzer with cylindrical electrodes produces more hydrogen than its counterpart with flat electrodes. • The approval of the two electrolysers is based on the same quantity of water to be electrolysed. [ABSTRACT FROM AUTHOR]

Molybdenum sulphide (2D-MoS 2) promises great potential as a hydrogen evolution (HER) catalyst, especially, when combined with conductive carbon supports like graphene oxide (GO) and carbon nanotubes (CNT). However, the hydrophobic nature of these carbon supports limits the catalytic potential of MoS 2. To overcome this, we introduced hydrophilic Nickel Boride (Ni 2 B) into GO/CNT electrodes (Ni 2 B-GO/CNT), enhancing wettability (Contact angle-25.3°) and HER activity. By hydrothermally depositing MoS 2 onto the hydrophilic Ni 2 B-GO/CNT electrode, we fabricated a self-supporting MoS 2 @Ni 2 B-GO/CNT electrode. The MoS 2 deposition led to the formation of MoS 2 @Ni 2 B-GO/CNT heterostructure with multiple interfaces, favoring interfacial electronic redistribution (XPS) to significantly improve the HER activity. Thus, the proposed MoS 2 @Ni 2 B-GO/CNT electrode exhibited an excellent durability of 100 h (97%) and an overpotential of 224 mV at 10 mA cm−2 in acidic medium. [Display omitted] • Hydrothermal growth of MoS 2 on Ni 2 B-GO/CNT to form a self-supporting electrode. • Hydrophilic Ni 2 B was incorporated into the GO/CNT matrix to enhance electrode wettability. • Enhanced HER catalytic activity from a heterostructure of MoS 2 with Ni 2 B, GO and CNT. • Excellent durability of MoS 2 @ Ni 2 B-GO/CNT was achieved for 100 h in acidic medium. [ABSTRACT FROM AUTHOR]

The simple addition of a Zn(II) precursor to a preoptimized poly(carboxylic acid) binder solution enhances the electrochemical performance and cycle life of silicon‐based electrodes. The binder/cation couple forms a cross‐linked coordinated binder that plays a key role in enhancing the mechanical and chemical stability of the electrode microstructure. The impact of the addition of the Zn precursor on the microstructural evolution of the electrode during cycling is investigated at different scales (from cell/electrode to silicon particle scale) using complementary operando, in situ, and ex situ X‐ray tomography techniques. Comparative analyses conducted on the reference and with Zn electrode formulations using operando and in situ X‐ray micro‐tomography allow for monitoring of the electrode morphological deformations along with the crack pattern formation and evolution during cycling. The benefits of the precursor addition include enhancing the mechanical stability of the electrode through a strengthened microstructure more apt to maintaining its integrity, as well as a better anchoring to the current collector leading to decreased electrical disconnections and capacity fade. Moreover, complementary ex situ X‐ray nano‐tomography measurements highlight the benefits of the precursor addition in terms of chemical stability with mitigated solid electrolyte interface (SEI) formation over the electrode cycling. [ABSTRACT FROM AUTHOR]

Pronounced compositional regulation and microstructure evolution have a significant influence on hydrogen electrocatalysis. Herein, for the first time, we demonstrate that N,Co-codoped carbon supported Co5.47N nanoparticles (Co5.47N/N,Co-C-800) derived from a nitrogen-rich porphyrin-bridged covalent triazine polymer (CoTAPPCC) are an effective electrocatalyst for the HER in 1.0 M KOH when compared to CoCo2O4/N,Co-C-900 (pyrolysis at 900 °C) and CoO/N,Co-C-1000 (pyrolysis at 1000 °C). The structural and morphological variations of CoTAPPCC at different heat treatment temperatures were investigated through various spectroscopic techniques. We reveal that electrocatalytic HER activity is temperature- and component-dependent. The overpotentials for Co5.47N/N,Co-C-800 to reach current densities of 10 and 100 mA cm-2 were determined to be 76 and 229 mV, respectively, outperforming many other state-of-the-art HER electrocatalysts. This work also sheds light on the influence of calcination temperature on the electrocatalytic HER of final samples. [ABSTRACT FROM AUTHOR]

Rational design of high-efficiency, durable and cost-effective electrocatalysts for H 2 production is essential to accelerate hydrogen production from fundamental experiments to practical industrial applications. Herein, cobalt-nickel-iron phosphides are constructed on Ni foam (CoNiFeP@NF) via a simple one-step electrochemical deposition method as self-supported electrodes for efficiently water splitting. The introduction of Fe element significantly enhances the catalytic properties of CoNiP@NF electrode for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Additionally, the optimal HER and OER electrodes are obtained by adjusting the Fe3+ concentration at 0.1 (CoNiFeP@NF-0.1) and 0.15 M (CoNiFeP@NF-0.15), respectively. Benefiting from the modulation of the electronic structure of CoNiP by the Fe element, CoNiFeP@NF-0.1 and CoNiFeP@NF-0.15 electrodes only require the overpotentials (η) of 48 mV for HER and 223 mV for OER to reach the current density of 10 mA cm−2, superior to the reference CoNiP@NF electrode (η 10, HER = 89 mV, η 10, OER = 333 mV). Subsequently, the electrolyzer constructed by CoNiFeP@NF-0.1 as cathode and CoNiFeP@NF-0.15 as anode exhibits excellent overall water splitting performance with a cell voltage of 1.56 V at a current density of 10 mA cm−2. This work provides a convenient and effective strategy for regulating the catalytic activity of bifunctional phosphide catalysts for water splitting. [Display omitted] • The cobalt-nickel-iron phosphides are successfully constructed on Ni foam via electrodeposition. • The catalytic activity can be optimized with the Fe3+ concentration. • CoNiFeP-0.1@NF presents a low overpotential (η 10 = 48 mV) toward HER. • CoNiFeP-0.15@NF presents a low overpotential (η 10 = 223 mV) toward OER. • CoNiFeP-0.15@NF displays excellent durability for OER. [ABSTRACT FROM AUTHOR]

Electrochemical analysis of U 60 nanoclusters (Li 40 K 20 [UO 2 (O 2)(OH)] 60 (H 2 O) 214) and their natural analog, the mineral studtite (UO 2)O 2 (H 2 O) 2 ·(H 2 O) 2 , was carried out using cyclic voltammetry with a powder microelectrode setup. Voltammetric analysis was supplemented by ab initio quantum mechanical modeling to understand the mechanism, thermodynamics, and structural changes during redox transition (with a semi-quantitative kinetics evaluation). This research aims to better understand the redox behavior and transport of dissolved and structural (incorporated) uranyl units in the environment. Further analysis is performed to determine if redox switching of actinyl ions in clusters can be performed while leaving the cluster intact or at what redox transition it disintegrates. Quantum-mechanical calculations were applied to approximate electrochemical peak potential shifts and add them to standard reduction potentials to more accurately assign peaks to specific redox transitions between different species. These peak potentials are calculated from oxidation state-dependent binding energies between different uranyl species either within or adsorbed to U 60. This theoretical approach incorporates extensive error cancellation and serves to predict electrochemical redox potentials and identify the reaction taking place. Voltammograms of U 60 in electrolyte solutions exhibit kinetically-inhibited coupled redox peaks assigned to the U(VI)/U(V) transition of cluster structural uranyl units at −0.34 V (vs. standard hydrogen electrode), indicative of U 60 reduction from UO 2 2+ to UO 2 +. The U(V)/U(IV) transition at −0.71 V is assigned to the subsequent U 60 reduction of UO 2 + to UO 2 0. A method of observing these transitions in situ using synchrotron x-ray absorption spectroscopy was explored. Voltammetry, modeling, and peak analysis indicate a kinetically-inhibited two-step, one-e- (per step) reduction of U 60 from U(VI) to U(V) to U(IV). Voltammetry and x-ray absorption spectroscopy measurements performed before and after exhaustive cycling and the highly stable nature of U 60 provide evidence that clusters typically do not break apart upon reduction. Voltammograms of U 60 collected in varied uranyl solutions are indicative of UO 2 2+ adsorption to the cluster surface and its subsequent reduction at +0.24 V (U(VI)/U(V)) and −0.05 V (U(V)/U(IV)). For uranyl solutions in electrolyte, the two-step, one-e- (per step) reduction of U 60 is superseded by uranyl adsorption from solution to the electrode surface with subsequent reduction via U(V) disproportionation. This study represents the sole electrochemical investigation of U 60 in the literature and only the second of any uranyl peroxide nanocluster. It is also one of the first to use quantum–mechanical approaches in combination with existing solution-based standard reduction potentials to calculate Pourbaix (E H -pH) diagrams for adsorbed and structural species. [ABSTRACT FROM AUTHOR]

Recently, tungsten oxide (WO 3) and bismuth vanadate (BiVO 4) have been considered as an intriguing combination for constructing a heterojunction for efficient photoelectrochemical (PEC) applications. Herein, we report the preparation of ternary WO 3 /BiVO 4 /NiCo layered double hydroxide (LDH) photoanodes for boosting photogenerated carrier transport and promotion of catalytic activity. WO 3 /BiVO 4 heterostructures were synthesized by a hydrothermal process of WO 3 nanoplates on a fluorine-doped tin oxide (FTO) glass substrate, followed by spin-coating for BiVO 4 materials. We investigated the effect of a NiCo LDH catalyst on PEC performance by controlling the growth temperatures of the NiCo LDH via hydrothermal synthesis. Moreover, the X-ray diffraction (XRD), Fourier‒transform infrared (FTIR) and X‒ray photoelectron spectroscopy (XPS) analyses revealed that the WO 3 /BiVO 4 heterojunction was retained after the NiCo LDH growth process regardless of synthesis temperatures. The PEC results verified that the WO 3 /BiVO 4 heterostructure with the optimized NiCo LDH catalyst (WBN60) possessed the best photocurrent density of 3.2 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE), which created improved charge separation and surface oxidation kinetics of photogenerated carriers. Consequentially, the smallest charge transfer resistance and recombination rate were achieved in the WBN60 electrode compared to others, indicating a much lower photoelectrode‒electrolyte interfacial resistance and the enhancement of photogenerated carrier transport by suppressing recombination. [ABSTRACT FROM AUTHOR]

Green hydrogen (H2) production from solar water splitting necessitates photoelectrodes with superior photoelectrochemical (PEC) activity and durability. However, surface defects and photocorrosion instability—especially at high potentials—limit PEC performance and stability. Herein, the prototypical bismuth vanadate (BiVO4) photoanode is used to demonstrate a holistic approach to improve photocurrent density and long‐term stability. In this approach, high surface‐area nanostructuring of BiVO4 is combined with barium (Ba) doping with semi‐crystalline hafnium oxide (HfO2) surface passivation and single‐atom nickel platinum (NiPt) catalysts. The introduction of Ba2+ ions into BiVO4 increases the concentration of conductive V4+ ions or the ratio of V4+ ions to oxygen vacancies, avoiding V5+ dissolution during water oxidation. The semi‐crystalline HfO2, which serves as a passivation layer, prevents BiVO4 photocorrosion by suppressing harmful chemical reactions when holes are transferred to the electrolyte. The synergistic use of isolated single‐atom and Ni‐Pt coordination improves charge transfer at the photoanode/electrolyte interface, leading to enhanced PEC kinetics and stability. As a result, a photoelectrode is demonstrated with ≈6.5 mA cm−2 at 1.23 V versus a reversible hydrogen electrode (RHE) and continuous operation for 800 h with a negligible degradation rate. This work provides a promising approach to improve photoanodes for PEC H2 production. [ABSTRACT FROM AUTHOR]

It is crucial to develop a non‐precious metal catalyst with high efficiency, affordable cost, and minimal environmental impact for conducting research on the oxygen reduction reaction (ORR) in fuel cells. In this study, BaFe12O19 functional porous carbon (BaFe12O19/PC) nanocomposite was successfully prepared using Fe2O3, BaCO3 and glucose as precursors. Meanwhile, the BaFe12O19/PC catalyst‐modified glassy carbon electrode, carbon rod, and Hg/HgO electrode were used as the working electrode, counter electrode, and reference electrode, respectively, to investigate the electrochemical behavior. The uniform distribution of nano‐scale BaFe12O19 particles in a porous carbon framework was confirmed by field emission scanning electron microscopy characterization. In addition, a double‐layer interface (Fe/Fe3C) was formed between the porous carbon and the nano‐sized BaFe12O19 particles. Fe/Fe3C has a synergistic effect with C, facilitating the migration and transfer of electrons from BaFe12O19 to porous carbon. The BaFe12O19/PC nanocomposite exhibited a four‐electron pathway for electrocatalytic kinetics, showcasing a significantly elevated half‐wave potential of 0.77 V, an impressively reduced Tafel slope of 84.95 mV/dec, and exceptional tolerance towards methanol. It is important to highlight that the BaFe12O19/PC nanocomposite not only possess high catalytic activity for oxygen reduction reactions (ORR), but also demonstrate excellent stability. Consequently, this synthesized BaFe12O19/PC nanocomposite hold promising prospects as cost‐effective and efficient catalysts in fuel cell applications. [ABSTRACT FROM AUTHOR]

Nickel/oxygen ion conducting ceramic composite powders (Ni/YSZ) are commonly used materials for fuel electrodes of solid oxide fuel cells and electrolyzers. One of the ways for increasing the activity of Ni/YSZ is infiltration/impregnation, where a formed porous electrode is impregnated with solutions of active elements, followed by thermolysis. In this study, Ni/YSZ electrodes simultaneously impregnated with nickel and ceria particles in different ratios are investigated. It is shown that the introduction of highly dispersed nickel only slightly increases the activity of the Ni/YSZ electrode and does not affect the pathway of the hydrogen oxidation reaction. If a minor amount of ceria particles is introduced into the electrode, it significantly increases its activity and partially changes the reaction mechanism. The best performance is obtained for the electrode impregnated with an equal volume solution of nickel and cerium nitrates. The polarization resistance of such an electrode in wet hydrogen is about 0.05 and 0.17 Ohm cm2 at 850 and 600 °C, respectively, which is about 10 and 65 times lower compared to initial Ni/YSZ. Long-term tests of more than 1100 h in a wet hydrogen atmosphere at 700 °C showed satisfactory stability of polarization resistance of all investigated electrodes. [Display omitted] • Ni/YSZ electrodes infiltrated with nickel and/or ceria were investigated. • The injection of nickel resulted in a negligible enhancement of Ni/YSZ activity. • Introduction of minor amounts of ceria leads to a partial change in HOR mechanism. • Introduction of close amounts of nickel and cerium is most effective. • Introduction of a significant amount of ceria completely changes the HOR mechanism. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrate reduction reaction (NO3RR) can convert nitrate contaminants into ammonia with higher added value. However, due to the NO3RR involving complex multi‐electron reactions, there is an urgent need to develop efficient electrocatalysts. Herein, CoCu Janus nanoparticles loaded on Ti3C2Tx MXene (CoCu‐Ti3C2Tx) is synthesized via the combination of molten salt etching and galvanic replacement strategy. The tandem catalysis of CoCu Janus NPs can maintain the balance between nitrogenous intermediates and active hydrogen (Hads). CoCu‐Ti3C2Tx exhibits a high NH3 yield of 8.08 mg h−1 mgcat.−1 and a satisfactory Faradaic efficiency of 93.6% at −0.7 V versus reversible hydrogen electrode (RHE). The Zn‐NO3− battery assembled with CoCu‐Ti3C2Tx shows an excellent power density of 10.33 mW cm−2, an NH3 yield of 1.52 mg h−1 mgcat.−1 and a Faradaic efficiency of 95.3% at 10 mA cm−2, which enables the simultaneous elimination of nitrate pollutants, ammonia production, and energy supply. Moreover, a series of verification experiments and density functional theory calculation are combined to reveal the reaction path and tandem catalytic mechanism. This work not only provides a new inspiration for the design of tandem catalysts but also promotes the development of Zn‐nitrate battery. [ABSTRACT FROM AUTHOR]

The performance of electrocatalysts is critical for renewable energy technologies. While the electrocatalytic activity can be modulated through structural and compositional engineering following the Sabatier principle, the insufficiently explored catalyst-electrolyte interface is promising to promote microkinetic processes such as physisorption and desorption. By combining experimental designs and molecular dynamics simulations with explicit solvent in high accuracy, we demonstrated that dimethylformamide can work as an effective surface molecular pump to facilitate the entrapment of oxygen and outflux of water. Dimethylformamide disrupts the interfacial network of hydrogen bonds, leading to enhanced activity of the oxygen reduction reaction by a factor of 2 to 3. This strategy works generally for platinum-alloy catalysts, and we introduce an optimal model PtCuNi catalyst with an unprecedented specific activity of 21.8 ± 2.1 mA/cm2 at 0.9 V versus the reversible hydrogen electrode, nearly double the previous record, and an ultrahigh mass activity of 10.7 ± 1.1 A/mgPt. [ABSTRACT FROM AUTHOR]

Electrocatalysts based on high‐valent indium are promising for formate production via CO2 electroreduction. However, reconstruction often occurs during the reaction progress, resulting in a decline in catalytic performance. Here, a composite of In2O3/In2S3 is developed, and its catalytic performance exceeds that of either individual phase, particularly in stability. Analysis of morphology, valence state, and in situ Raman spectroscopy reveals that In2O3 is well preserved during the reaction. Theoretical calculations suggest that the desorption energy of lattice oxygen on In2O3 can be strengthened due to In2O3‐In2S3 bonding within the composite. This reinforcement facilitates the formation of more active sites and promotes CO2 adsorption, further decreasing the energy barrier of formate production to only 0.12 eV. As a result, the composite exhibits a formate selectivity over 95.05% at –1.13 V vs reversible hydrogen electrode accompanied by a partial current density of 434.4 mA cm–2. Notably, the selectivity of formate maintains over 95% even after 50 h at an industrial‐level current density of 200 mA cm–2, 17 times longer than the individual phase. Furthermore, 18.33% solar‐to‐formate and 19.49% solar‐to‐fuel are obtained when coupled with III‐V solar cells, demonstrating its feasibility. [ABSTRACT FROM AUTHOR]

Facilitating equilibrium in the nitrogen cycle, electrochemical nitrate reduction (NitRR) to ammonia stands as a carbon‐free method for ammonia synthesis. Copper‐based catalysts, renowned for NitRR, face a hurdle in supplying sufficient hydrogen radicals (*H) for efficient hydrogenation of NitRR intermediates. Addressing this, NiMoO4 is leveraged as an excellent *H donor, synergistically coupling it with a copper‐based catalyst. The work introduces a high‐performance NiMoO4/CuO nanowire (NW)/Copper foam (CF) catalyst for NitRR, achieving a remarkable Faraday efficiency (FE) of 98.8% and a yield of 0.8221 mmol cm−2 h−1. Operating at −0.2 V versus reversible hydrogen electrode (vs RHE) in an H‐type electrolytic cell, the catalyst demonstrates exceptional stability over 20 h. Additionally, coupling NitRR with an air stripping process enables efficient collection of NH4Cl products, offering a practical avenue for converting waste nitrates into valuable ammonia products. In‐depth in situ electrochemistry and density‐functional theory (DFT) calculations affirm the transformation of CuO into Cu/Cu2O during the electrocatalytic reduction process. Cu/Cu2O catalyzes nitrate conversion to nitrite, while NiMoO4, serving as a *H donor, facilitates deoxidation and hydrogenation of other N intermediates on the Cu/Cu2O surface, effectively driving the reduction of nitrate to ammonia. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) loaded catalysts show high activity and selectivity for ammonia (NH3) synthesis via electrochemical reduction of nitrate (NO3−), but their practical application is still restricted by their high cost and insufficient stability. Herein, a multi‐component electrocatalyst of Ru nanoclusters loaded on phosphorus‐doped/phosphate‐modified and oxygen vacancy (OV)‐rich Fe/Fe3O4 composite nanorods (Ru@P‐Fe/Fe3O4) to synergistically promote electrocatalytic NO3− reduction reaction (NO3−RR)‐to‐NH3 performance via strong metal‐support interaction (SMSI) is reported. Impressively, the best Ru@P‐Fe/Fe3O4 catalyst exhibits outstanding NO3−RR activity, selectivity, and durability in 0.1 M KNO3 + 0.5 M KOH solution, with an NH3 yield rate of 14.37 ± 0.21 mgNH3 h−1 cm−2 (1710.71 ± 25 mgNH3 h−1 mgRu−1) at −0.75 V versus reversible hydrogen electrode (vs. RHE), an NH3 Faradaic efficiency (FE) of 97.2% at −0.55 V vs. RHE, and a superior stability over 50 h, suppressing most of reported Fe‐based and Ru‐based electrocatalysts. The characterizations and theoretical calculations unveil that the SMSI between Ru nanoclusters and P‐Fe/Fe3O4 composite nanorods can promote the generation of OV, tune the electronic structure of Ru species, and stabilize Ru nanoclusters, thereby reducing the reaction energy barrier of NO3−RR‐to‐NH3, inhibiting the competitive hydrogen evolution reaction, and boosting the NH3 yield rate NH3 FE, and stability. [ABSTRACT FROM AUTHOR]

Formic acid (HCOOH) is a highly energy efficient product of the electrochemical CO2 reduction reaction (CO2RR). Bismuth‐based catalysts have shown promise in the conversion of CO2 to formic acid, but there is still a great need for further improvement in selectivity and activity. Herein, we report the preparation of Bi nanosheets decorated by cerium oxide nanoparticles (CeOx) with high Ce3+/Ce4+ ratio and rich oxygen vacancies. The CeOx nanoparticles affect the electronic structures of bismuth, enhance CO2 adsorption, and thus promote the CO2RR properties of Bi nanosheets. Compared with elemental Bi nanosheets, the hetero‐structured CeOx/Bi nanosheets exhibit much higher activity over a wide potential window, showing a current density of 16.1 mA cm−2 with a Faradaic efficiency of 91.1% at −0.9 V vs. reversible hydrogen electrode. [ABSTRACT FROM AUTHOR]

Copper (Cu)‐based catalysts have established their unique capability for yielding wide value‐added products from CO2. Herein, we demonstrate that the pathways of the electrocatalytic CO2 reduction reaction (CO2RR) can be rationally altered toward C1 or C2+ products by simply optimizing the coordination of Cu with O‐containing organic species (squaric acid (H2C4O4) and cyclohexanehexaone (C6O6)). It is revealed that the strength of Cu−O bonds can significantly affect the morphologies and electronic structures of derived Cu catalysts, resulting in the distinct behaviors during CO2RR. Specifically, the C6O6−Cu catalysts made up from organized nanodomains shows a dominant C1 pathway with a total Faradaic efficiency (FE) of 63.7 % at −0.6 V (versus reversible hydrogen electrode, RHE). In comparison, the C4O4−Cu with an about perfect crystalline structure results in uniformly dispersed Cu‐atoms, showing a notable FE of 65.8 % for C2+ products with enhanced capability of C−C coupling. The latter system also shows stable operation over at least 10 h with a high current density of 205.1 mA cm−2 at −1.0 VRHE, i.e. is already at the boarder of practical relevance. This study sheds light on the rational design of Cu‐based catalysts for directing the CO2RR reaction pathway. [ABSTRACT FROM AUTHOR]

Creating affordable and efficient bifunctional electrocatalysts is crucial for producing clean hydrogen energy through complete water splitting. We describe a way to make S-doped carbon-encapsulated iron-nickel phosphide nanowires (S/FeNiP@C) using metal-organic frameworks. These nanowires exhibit exceptional electrocatalytic performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. The optimized S/FeNiP@C nanowires exhibit low overpotentials of 53 mV and 270 mV at a current density of 10 mA cm˗2 for HER and OER, respectively. They also have tiny Tafel slopes of 159 mV dec˗1 for HER and 50 mV dec˗1 for OER. The water electrolyzer uses S/FeNiP@C nanowires as both the anode and the cathode to reach a current density of 10 mA cm˗2 at a voltage of 1.61 V and stays very stable for 48 h. The great catalytic performance is mostly due to the simple carbon framework and low sulfur integration. This creates a large surface area for the catalyst and electrolyte to interact, allowing charge and mass to move quickly, and a lot of active sites that last a long time. [Display omitted] • A S/FeNiP@C nanowire catalyst was successfully prepared. • The S/FeNiP@C catalyst displays excellent HER and OER catalytic properties. • For HER and OER, the S/FeNiP@C catalyst performed well in alkaline conditions. • S/FeNiP@C has better alkaline water splitting activity. [ABSTRACT FROM AUTHOR]

Electrosynthesis of adipic acid (a precursor for nylon-66) from KA oil (a mixture of cyclohexanone and cyclohexanol) represents a sustainable strategy to replace conventional method that requires harsh conditions. However, its industrial possibility is greatly restricted by the low current density and competitive oxygen evolution reaction. Herein, we modify nickel layered double hydroxide with vanadium to promote current density and maintain high faradaic efficiency (>80%) within a wide potential window (1.5 ~ 1.9 V vs. reversible hydrogen electrode). Experimental and theoretical studies reveal two key roles of V modification, including accelerating catalyst reconstruction and strengthening cyclohexanone adsorption. As a proof-of-the-concept, we construct a membrane electrode assembly, producing adipic acid with high faradaic efficiency (82%) and productivity (1536 μmol cm−2 h−1) at industrially relevant current density (300 mA cm−2), while achieving >50 hours stability. This work demonstrates an efficient catalyst for adipic acid electrosynthesis with high productivity that shows industrial potential. Here, authors use a membrane electrode assembly is conducted to produce adipic acid with high faradaic efficiency and productivity at an industrially relevant current density, while achieving >50 hours stability. [ABSTRACT FROM AUTHOR]

A nanohybrid-modified glassy carbon electrode based on conducting polypyrrole doped with carbon quantum dots (QDs) was developed and used for the electrochemical detection of anti-tissue transglutaminase (anti-tTG) antibodies. To improve the polypyrrole conductivity, carrier mobility, and carrier concentration, four types of carbon nanoparticles were tested. Furthermore, a polypyrrole-modified electrode doped with QDs was functionalized with a PAMAM dendrimer and transglutaminase 2 protein by cross-linking with N-hydroxysuccinimide (NHS)/N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC). The steps of electrode surface modification were surveyed via electrochemical measurements (differential pulse voltammetry (DPV), impedance spectroscopy, and X-ray photoelectron spectroscopy (XPS)). The surface characteristics were observed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and contact angle measurements. The obtained modified electrode exhibited good stability and repeatability. DPV between − 0.1 and 0.6 V (vs. Ag/AgCl 3 M KCl reference electrode) was used to evaluate the electrochemical alterations that occur after the antibody interacts with the antigen (transglutaminase 2 protein), for which the limit of detection was 0.79 U/mL. Without the use of a secondary label, (anti-tTG) antibodies may be detected at low concentrations because of these modified electrode features. [ABSTRACT FROM AUTHOR]

The negative electric potential difference observed in a YSZ-based thin film potentiometric sensor at a low operating temperature of 673 K is investigated. The multilayered sensor is grown sequentially using pulsed laser deposition at 998 K with Cu-Cu2O reference electrode, YSZ electrolyte and Pt as working electrode respectively. The thickness of the Cu-Cu2O reference layer is a critical factor in thin film sensors as the Pt3O4 phase stabilized along with Cu-Cu2O can reach the YSZ interface. XRD, μ- Raman and XPS confirm the formation of the Pt3O4 phase on the reference side along with the Cu-Cu2O layer. However, the pure Pt3O4 phase could not be stabilized in the thin film without Cu-Cu2O. The presence of the Pt3O4 phase on the reference side generates a Pt-Pt3O4 reference couple with an equilibrium oxygen partial pressure of ~ 104 ppm higher than the sample oxygen pressure of 10-103 ppm giving rise to a negative electric potential difference with a sensitivity of -7.5 mV/decade. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) can be used as a fertilizer, a chemical or a new generation of fuel and has important agricultural and industrial value. Electrochemical NO3–-to-NH3 (NITRR) can realize the conversion of waste into treasure and waste resources, which is a promising method for ammonia synthesis. However, the process of NITRR is very complicated, resulting in product diversification and poor selectivity. In this work, an iron modified cerium oxide in rod form (Fe/CeO2-rod) catalysts was designed and used for the NITRR. The Fe/CeO2-rod catalyst showed excellent activity, and achieves high Faradaic efficiency (FE 95%) and NH3 yield rate (4.04 mg h–1 cm–2) in 0.1 M KOH electrolyte at – 0.52 V versus reversible hydrogen electrode. Furthermore, this catalyst exhibits a negligible activity decay during continuous electrolysis for 25 h. Further experiments provide the important role of Fe, which promote the formation of hydrogen radicals (H*). This study may provide new pathways to improve the activity of inexpensive catalysts for NITRR. [ABSTRACT FROM AUTHOR]

TiO 2 is one of the most promising photoanodes in photoelectrochemical (PEC) water-splitting due to its chemical stability, corrosion resistance, and cost-effectiveness. However, the TiO 2 nanoparticles with high surface area and fast electron transfer have been grown on a Ti foil substrate through dielectric barrier discharge (DBD) plasma using Ar/O 2 mixture gas. Optical emission spectroscopy (OES) was utilized to detect the reactive species existing in DBD plasma discharge during the process of treating titanium foil. The field emission scanning electron microscopy (FE-SEM) images revealed the morphology of TiO 2 nanoparticles aggregated to form a microwire structure on a Ti foil substrate. The X-ray diffraction (XRD) patterns agreed with the anatase phase of the monoclinic TiO 2 nanoparticles. PEC measurement showed that the synthesis of TiO 2 nanoparticles using Ar/O 2 DBD plasma for a duration of 3-min resulted in the highest photocurrent response. This response reached the highest photocurrent density of 1.92 mA/cm2 at 1.23 V vs. RHE (versus a reversible hydrogen electrode). The photoconversion efficiency (ŋ) improved from 1.31 to 1.85 as the plasma treatment time increased from 1 min to 3 min. The remarkable performance can be attributed to the large surface area of the nanoparticles and their low charge resistance. Transient photocurrent-time curves are utilized to demonstrate the stability and repeatability of TiO 2 nanoparticles. Ar/O 2 DBD plasma treatment is a promising superior method to enhance the functionality of TiO 2 in PEC water-splitting applications, as demonstrated in the literature comparison. [ABSTRACT FROM AUTHOR]

Water electrolysis plays a central role in the transition to a fossil‐free society, but there are significant challenges to overcome in order to increase its availability on a large scale. Alkaline water electrolysis is a mature and scalable technology, although it has several disadvantages compared to electrolyzers working in acidic environments. In particular, the use of highly alkaline aqueous electrolytes can lead to corrosion, and the achieved current densities are relatively low. This study addresses the latter limitation by introducing a gas diffusion electrode (GDE) setup as a novel development tool that bridges the gap between research and practical applications in commercial devices such as fuel cells and electrolyzers. A high surface area Ni foam catalyst that can sustain exceptional oxygen evolution reaction (OER) current densities of up to 4 A cm−2 in a quasi‐steady‐state within our GDE setup operating in an alkaline environment is presented. The high performance of this Ni‐based benchmark catalyst is attributed to its deposition onto a mesh‐like porous transport layer (PTL) via hydrogen‐templated electrodeposition. This forms a porous foam‐like structure that augments the mass transport of the gaseous reactants at the GDE. [ABSTRACT FROM AUTHOR]

Elucidation the relationship between electrode potentials and heterogeneous electrocatalytic reactions has attracted widespread attention. Herein we construct the well-defined Mn single-atom (MnSA) catalyst with four N-coordination through a simple thermal pyrolysis preparation method to investigate the electrode potential micro-environments effect on carbon dioxide reduction reactions (CO2RR) and oxygen reduction reactions (ORR). MnSA catalysts generate higher CO production Faradaic efficiency of exceeding 90% at −0.9 V for CO2RR and higher H2O2 yield from 0.1 to 0.6 V with excellent ORR activity. Density functional theory (DFT) calculations based on constant potential models were performed to study the mechanism of MnSA on CO2RR. The thermodynamic energy barrier of CO2RR is lowest at −0.9 V vs. reversible hydrogen electrode (RHE). Similar DFT calculations on the H2O2 yield of ORR showed that the H2O2 yield at 0.2 V was higher. This study provides a reasonable explanation for the role of electrode potential micro-environments. [ABSTRACT FROM AUTHOR]

Optimization of Pt atom utilization efficiency is critical for the development of proton-exchange-membrane fuel cells. Here we aim to develop an efficient oxygen reduction reaction (ORR) catalyst with a low Pt content through the concurrent modification of Pt-Co alloy catalysts and carbon substrate. In the present study, ultrafine Pt-Co alloy nanoparticles are successfully synthesized and stabilized by topological carbon defects via adopting the ammonia thermal treatment. Despite the low Pt loading, the obtained catalyst exhibits an impressive half-wave potential of 0.926 V versus the reversible hydrogen electrode in 0.1 M HClO4 electrolyte. Furthermore, the durability testing using the timed-current method demonstrates a tiny loss of only 3.6% after 12 h. Both experimental results and theoretical calculations demonstrate that topological carbon defects significantly enhance the charge transfer processes at the alloy/carbon interface, contributing to the strong electronic metal-support interactions between the Pt-Co alloy nanoparticles and topological carbon defects. These interactions, along with the alloy effect, play a crucial role in promoting the ORR performance in acidic media. [ABSTRACT FROM AUTHOR]

Integrated reference electrodes allow to deconvolute voltage contributions of anode and cathode and contribute to a better understanding of CO2 electrolyzers. However, in zero‐gap cell configurations, this integration can be challenging and obtaining error‐free data with such a setup is a non‐trivial task. This study compares five different methods to integrate a reference electrode into an alkaline zero‐gap CO2 electrolysis cell. Sources of error and measures to circumvent them are investigated and finite‐element simulation is used to gain a better understanding of observed effects. Placing a reference electrode into the inactive area of the cell is found to be a reliable method, as long as the placement of electrodes is sufficiently controlled. Sandwiching a wire quasi‐reference electrode between two membranes is especially useful for electrochemical impedance spectroscopy; however, it can affect the overall cell performance. Contacting the catalyst layer from the backside with a salt‐bridge is promising for localized measurements if sufficient reproducibility can be ensured. [ABSTRACT FROM AUTHOR]

Recently, lead halide perovskites have emerged as promising photoanode materials for efficient hydrogen production. However, the sluggish kinetics of the oxygen evolution reaction (OER) and interfacial defect‐mediated charge accumulation inevitably result in efficiency loss and degradation of perovskite photoanodes. Herein, a defect‐passivated electron transport layer‐based perovskite photoanode combined with a catalyst layer favorable is introduced for iodide oxidation reaction bearing a small thermodynamic barrier and rapid kinetics compared to OER for efficient solar fuel generation. The resulting perovskite photoanode revealed a saturated photocurrent density of 22.4 mA cm−2 at 0.3 V versus the reversible hydrogen electrode (VRHE) with an impressive onset potential of −0.2 VRHE as well as durability for 225 h in a neutral electrolyte. In addition, an unbiased hydrogen‐production device comprising a perovskite photoanode and Pt coil electrocatalyst is demonstrated, achieving a remarkable solar‐to‐chemical conversion efficiency of 11.45% and stable operation for 25 h. Moreover, a wireless artificial leaf‐structured device realizing solar‐driven hydrogen generation in natural sea water under outdoor sunlight is presented. [ABSTRACT FROM AUTHOR]

Aqueous zinc metal batteries (AZMBs) have emerged as a focal point of interest in academic research and industrial strategic planning. Zinc powder (ZP) is poised to assume a prominent position in both future research and practical applications due to its high Zn utilization rate and processability. However, critical challenges need to be addressed before realizing substantial progress. Notably, severe voltage polarization and gas production of ZP electrodes stand out as the primary causes of battery failure, differing with zinc foil where short circuits caused by zinc dendrites contribute to battery failure. While numerous comprehensive reviews have offered effective strategies for zinc foil, a systematic summary of ZP electrodes is still lacking. For ZP, electrode preparation dictates the performance. This review summarizes the criteria for optimal ZP electrodes, covering electrode components, preparation methods, and technique parameters. It emphatically introduces the underlying causes and strategies of water‐related side reactions and briefly analyzes the stripping/plating behaviors of ZP electrodes. The status quo of ZP‐based batteries is then discussed in categories of ZP, current collector, conductive scaffold, binder, and electrolytes. Finally, potential avenues for future research are proposed from three aspects to enhance the focus on ZP electrodes and facilitate the practical application of AZMBs. [ABSTRACT FROM AUTHOR]

Atomic Fe sites enabled electrochemical carbon dioxide (CO2) reduction (ECO2R) to carbon monoxide (CO) at low overpotentials. However, the narrow potential ranges for selective CO2 conversion on atomic Fe sites hindered the CO production at high current densities. Therefore, unveiling the CO2 electroreduction processes and clarifying the catalytic mechanisms on different atomic Fe sites are important for better design of atomic Fe catalysts toward efficient ECO2R. Herein, the ECO2R processes on single‐atom, dual‐atom, and cluster Fe sites are systematically investigated, and clarify that the balanced water dissociation and CO2 protonation on dual‐atom Fe sites promote the efficient CO production. The dual‐atom Fe catalyst achieves Faradaic efficiencies of CO (FECO) above 92% over a wide potential range of −0.4–−0.9 V versus reversible hydrogen electrode and maintains FECO of 91% after 153‐h electrolysis in H‐type cell. Benefitting from the favorable CO2 protonation for ECO2R on dual‐atom Fe sites, pH‐universal CO2 electroreduction is achieved in alkali‐/acid‐/bicarbonate‐fed membrane electrode assembly electrolyzer, with FECO exceeds 98% in strongly acidic/alkaline and neutral mediums. The work reveals a water dissociation‐promoted CO2 electroreduction on dual‐atom Fe sites and presents a feasible regulation of atomic Fe sites for highly active/selective ECO2R. [ABSTRACT FROM AUTHOR]

The quest for sustainable and clean energy sources has intensified research on the Hydrogen Evolution Reaction (HER) in recent decades. In this study, we have presented a novel Ce‐doped TiO2 catalyst synthesized through the sol‐gel method, showcasing its potential as a superior electrocatalyst for HER in an acidic medium. Comprehensive characterization through X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Energy dispersive X‐ray (EDX), and Raman spectroscopy confirms the successful formation of the catalyst. Electrocatalytic performance evaluation, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and Tafel analysis, demonstrates that GCE‐5wt.%CeTiO2 outperforms bare GCE, as well as Ce and TiO2‐based electrodes. Kinetic investigations reveal a Tafel slope of 105 mV dec−1, indicating the Volmer step as the rate‐determining step. The onset potential for HER at GCE‐5wt.%CeTiO2 is −0.16 V vs. RHE, close to the platinum electrode. Notably, the catalyst exhibits a low overpotential of 401 mV to achieve a current density of 10 mA cm−2 with an impressive 95 % Faradaic efficiency. Furthermore, the catalyst demonstrates outstanding durability, maintaining a negligible increase in overpotential during a 14‐hour chronoamperometry test. These results have far‐reaching implications for the development of cost‐effective and efficient electrocatalysts for hydrogen production. [ABSTRACT FROM AUTHOR]

Discovering a competent charge transport layer promoting charge separation in photoelectrodes is a perpetual pursuit in photoelectrochemical (PEC) water splitting to achieve high solar‐to‐hydrogen (STH) conversion efficiency. Here, a conjugated polythiophene framework (CPF‐TTB) on Ta3N5 is elaborately electropolymerized, substantiating the hole transport behavior in their heterojunction. Tailored band structures of the CPF‐TTB/Ta3N5 reinforce the separation of photogenerated carriers, elevating a fill factor of the photoanode modified with a cocatalyst. The enhanced hole extraction enables the NiFeOx/CPF‐TTB/Ta3N5/TiN photoanode to generate a remarkable water oxidation photocurrent density of 9.12 mA cm−2 at 1.23 V versus the reversible hydrogen electrode. A tandem device combining the photoanode with a perovskite/Si solar cell implements an unbiased solar water splitting with a STH conversion efficiency of 6.26% under parallel illumination mode. This study provides novel strategies in interface engineering for metal nitride‐based photoelectrodes, suggesting a promise of the organic–inorganic hybrid photoelectrode for high‐efficiency PEC water splitting. [ABSTRACT FROM AUTHOR]

Liquid metal alloys can accumulate specific solute metal atoms on their surface, creating distinct quasi‐ordered atomic layers. Such atomic layers can be tuned by varying the alloy composition to form catalytic interfaces suited for multi‐step reactions. Here, the surface enrichment in gallium‐indium alloys is studied and utilized for carbon dioxide (CO2) electrochemical reduction. The results show that adding a small amount of indium (16.8 at%) to gallium leads to a significant indium enrichment of >83 at% on the topmost layer of the alloy. This enrichment dictates the CO2 conversion pathway, leading to 98% faradaic efficiency toward formate at −1.90 V vs reversible hydrogen electrode (RHE). This study produces unprecedented insights into key interfacial processes and lays the foundation for significant further work within the areas of catalysis and liquid metals. [ABSTRACT FROM AUTHOR]

The electrochemical conversion of glycerol into high-value chemicals through the selective glycerol oxidation reaction (GOR) holds importance in utilizing the surplus platform chemical component of glycerol. Nevertheless, it is still very limited in producing three-carbon chain (C3) chemicals, especially glyceric acid/glycerate, through the direct oxidation of its primary hydroxyl group. Herein, Pd microstructure electrodeposited on the Ni foam support (Pd/NF) is designed and fabricated to achieve a highly efficient GOR, exhibiting a superior current density of ca. 120 mA cm−2 at 0.8 V vs. reversible hydrogen electrode (RHE), and high selectivity of glycerate at ca. 70%. The Faradaic efficiency of C3 chemicals from GOR can still be maintained at ca. 80% after 20 continuous electrolysis runs, and the conversion rate of glycerol can reach 95% after 10-h electrolysis. It is also clarified that the dual-component interfaces constructed by the adjacent Pd and Ni sites are responsible for this highly efficient GOR. Specifically, Ni sites can effectively strengthen the generative capacity of the active adsorbed hydroxyl (OHad) species, which can steadily immigrate to the Pd sites, so that the surface adsorbed glycerol species are quickly oxidized into C3 chemicals, rather than breaking the C–C bond of glycerol; thus, neither form the C2/C1 species. This study may yield fresh perspectives on the electrocatalytic conversion of glycerol into high-value C3 chemicals, such as glyceric acid/glycerate. [ABSTRACT FROM AUTHOR]

Developing a hydrogen evolution reaction (HER) electrocatalyst that can steadily drive a large current density is of great significance for industrial electrochemical water‐splitting technology. Herein, the compositionally complex noble‐metal‐lean system Co–Cu–Mo–Pd–Re is investigated for alkaline HER by a scanning droplet cell‐assisted high‐throughput screening of co‐sputtered thin‐film material libraries. The identified hit compositions are used to prepare a catalyst‐coated Ni foam‐based layer that is hot‐pressed with a specifically designed PEEK‐covered carbon‐based gas diffusion layer to obtain a novel‐design gas diffusion electrode (GDE). H2 bubbles that collect on the electrode surface are effectively reduced by controlling the hydrophobicity of the catalyst layer of the GDE, hence enabling a high current (−1 A cm−2) operation for HER in alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

The design of bifunctional electrocatalysts toward reduction reaction of carbon dioxide (ECO2RR) and oxygen evolution reaction (OER) in aqueous rechargeable Zn─CO2 batteries (ZABs) still poses a significant challenge. Herein, Ni clusters (Nix) of 0.5 and 0.8 nm in diameter coupled with single Ni site (Ni−N4−C), denoted as Ni−N4/Ni5 and Ni−N4/Ni8, respectively, are synthesized and the size effect of Ni nanoclusters are studied. Ni−N4/Ni5 exhibits an ≈100% Faradaic efficiency (FECO) toward ECO2RR for CO from −0.4 to −0.8 V versus the reversible hydrogen electrode, superior to that of Ni−N4−C (FECO = 55.0%) and Ni−N4/Ni8 (FECO = 80.0%). The OER performance of Ni−N4/Ni5 and Ni−N4/Ni8 are superior or comparable to that of commercial RuO2 but outperform that of Ni−N4−C. Theoretical calculation indicates that *COOH of ECO2RR intermediates bond synergistically with Nix clusters and Ni−N4−C single atom site, promoting the activation of CO2 and reducing the energy barrier of the potential determining step of ECO2RR. Such effect is strongly size‐dependent and larger Nix nanoclusters result in too strong binding of *COOH intermediates, impede the formation of *CO. As a bifunctional cathode electrocatalyst of rechargeable alkaline aqueous ZABs, Ni−N4/Ni5 exhibits a peak power density of 11.7 mW cm−2 and cycling durability over 1200 cycles and 420 h. [ABSTRACT FROM AUTHOR]

The development of effective and selective catalysts is the key to improving the multi-electron transfer nitrate reduction reaction (NO3−RR) to ammonia (NH3). Herein, we prepared a copper–tin bimetallic alloy using the dynamic hydrogen bubble template electrodeposition technique for electrocatalytic NO3− reduction to NH3. The NH3 yield rate and the faraday efficiency were up to 293.12 μmol h−1 cm−2 and 78.57% at −1.2 V versus reversible hydrogen electrode in 0.1 M Na2SO4 (containing 0.01 M NaNO3) electrolyte. This paper will provide new suggestions for the use of bimetallic alloys for electrochemical removal of nitrate and ammonia synthesis from water. [ABSTRACT FROM AUTHOR]