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As an effective decoupling and quantification tool, reference electrodes (REs) are increasingly utilized in the development of high‐performance and high‐safety lithium (Li) batteries. However, it is still challenging to construct durable REs in practical battery systems given the sophistication of multi‐field interactions. In this contribution, the two‐stage failure mechanism of Li metal REs set inside working batteries is determined, including the active material loss period due to spatial redistribution behavior and then accelerated failure period based on mixed potential theory, which greatly threatens the dynamic service lifespan of REs. Furthermore, the targeted encapsulation strategy is proposed to control the structural vulnerability issue of Li metal REs. Compared to the unmodified RE, the encapsulated RE is validated feasible to kinetically mitigate the redistribution current through it via designed model experiments. Benefited from the improved structural stability, the encapsulated RE achieved twofold lifetime prolongation in 1 Ah pouch full cells during cycling. This work reveals the neglected structural failure mechanism of Li metal REs in operation and provides fresh design implications toward more durable REs in working batteries, with which deeper insights into battery landscape will be acquired. [ABSTRACT FROM AUTHOR]

Battery materials research is of crucial importance to the development of next‐generation batteries. However, the transition from lab‐scale studies, typically in gram quantities, to industrially relevant ones (i.e., kilogram scale) has been holding back by challenges in scale‐up synthesis and a lack of reliable approaches to verify the electrochemical performance of the lab‐made materials. Here the design and assembly procedures of sub‐Ah‐scale pouch cells that provide validations of several lab‐made Li‐ion and Na‐ion cathode materials available in a limited quantity (<5 g) are reported. These lab‐made pouch cells show superior cycle stability and consistency over the widely used coin cells, exemplified by multiple Ni‐rich layered oxide‐graphite full batteries retaining 84.29 ± 0.16% of the initial capacities over 1000 cycles. A four‐electrode pouch cell with a reparable reference electrode is further designed to monitor impedance growth and Li plating during long‐term electrochemical tests. It can be further integrated with in situ ultrasonic imaging to enable multi‐modal studies. This work provides a powerful platform to evaluate and boost the technology readiness levels of laboratory‐discovered battery materials. [ABSTRACT FROM AUTHOR]

Dissolved lead is a serious but common health hazard in drinking water, yet there is still no practical way to monitor its levels continuously in the distribution system or at the point of use. Here we propose using a lead-selective membrane on top of a chemiresistive device to continuously measure Pb2+ ion concentrations in real time. The detection limit was lowered by stabilizing the surface of the resistive film with sodium hydroxide and 15-crown-5 ether and optimizing the sensor geometry to maximize the effective surface area. The detection mechanism is based on the complexation of the Pb2+ ions by the lead ionophores within the membrane, thus modulating the interactions between the ionophores and the chemiresistive film. The limit of detection of the fabricated devices was reliably below 2 μg L−1, with concentrations up to 3 mg L−1 routinely quantifiable over several measurement cycles. The chemiresistive sensors can thus achieve lower detection limits than potentiometric devices while being more robust and simpler to fabricate by omitting the reference electrode. Ion-selective membrane-covered chemiresistors can therefore be deployed to continuously monitor drinking water sources and detect harmful levels of lead in real time. [ABSTRACT FROM AUTHOR]

Fast-scan cyclic voltammetry (FSCV) is a widely used technique for detecting neurotransmitters. However, electrode fouling can negatively impact its accuracy and sensitivity. Fouling refers to the accumulation of unwanted materials on the electrode surface, which can alter its electrochemical properties and reduce its sensitivity and selectivity. Fouling mechanisms can be broad and may include biofouling, the accumulation of biomolecules on the electrode surface, and chemical fouling, the deposition of unwanted chemical species. Despite individual studies discussing fouling effects on either the working electrode or the reference electrode, no comprehensive study has been conducted to compare the overall fouling effects on both electrodes in the context of FSCV. Here, we examined the effects of biofouling and chemical fouling on the carbon fiber micro-electrode (CFME) as the working electrode and the Ag/AgCl reference electrode with FSCV. Both fouling mechanisms significantly decreased the sensitivity and caused peak voltage shifts in the FSCV signal with the CFME, but not with the Ag/AgCl reference electrode. Interestingly, previous studies have reported peak voltage shifts in FSCV signals due to the fouling of Ag/AgCl electrodes after implantation in the brain. We noticed in a previous study that energy-dispersive spectroscopy (EDS) spectra showed increased sulfide ion concentration after implantation. We hypothesized that sulfide ions may be responsible for the peak voltage shift. To test this hypothesis, we added sulfide ions to the buffer solution, which decreased the open circuit potential of the Ag/AgCl electrode and caused a peak voltage shift in the FSCV voltammograms. Also, EDS analysis showed that sulfide ion concentration increased on the surface of the Ag/AgCl electrodes after 3 weeks of chronic implantation, necessitating consideration of sulfide ions as the fouling agent for the reference electrodes. Overall, our study provides important insights into the mechanisms of electrode fouling and its impact on FSCV measurements. These findings could inform the design of FSCV experiments, with the development of new strategies for improving the accuracy and reliability of FSCV measurements in vivo. [ABSTRACT FROM AUTHOR]

In order to accurately determine the mass balance of hydrogen in steel sheet in electrochemical hydrogen permeation tests, channel flow double electrode (CFDE) technique was combined with the Devanathan-Stachurski (DS) cell. One side of a steel sheet was used as the hydrogen entry electrode in the DS cell and as the generator electrode in the CFDE. The back side of the steel sheet was anodically polarized in NaOH solution for hydrogen withdrawal, and anodic polarization of the platinum detector electrode for CFDE was performed for molecular hydrogen that did not enter the steel sheet while cathodic polarization of the hydrogen entry electrode in Na 2 SO 4 solution. The mass balance obtained from the mass of adsorbed hydrogen, the mass of permeated hydrogen, and the mass of evolved hydrogen enabled quantitative analysis of the hydrogen un-permeated in the steel sheet. • CFDE-DS cell was developed to quantify non-adsorbed hydrogen in sample membrane. • Mass balance of hydrogen during permeation test was considered for the first time. • Hydrogen absorption reaction on entry side electrode proceeds in Volmer process. • Mass of hydrogen absorbed at entry interface was fixed after irreversible trapping. [ABSTRACT FROM AUTHOR]

A Fe-Co dual-metal co-doped N containing the carbon composite (FeCo-HNC) was prepared by adjusting the ratio of iron to cobalt as well as the pyrolysis temperature with the assistance of functionalized silica template. Fe1Co-HNC, which was formed with 1D carbon nanotubes and 2D carbon nanosheets including a rich mesoporous structure, exhibited outstanding oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic activities. The ORR half-wave potential is 0.86 V (vs. reversible hydrogen electrode, RHE), and the OER overpotential is 0.76 V at 10 mA cm−2 with the Fe1Co-HNC catalyst. It also displayed superior performance in zinc–air batteries. This method provides a promising strategy for the fabrication of efficient transition metal-based carbon catalysts. [ABSTRACT FROM AUTHOR]

Bi-based materials are promising catalysts for electrochemical reduction of carbon dioxide (CO2) to formate, but remain challenging in terms of activity and stability. Herein, we report the facile synthesis of Zn-doped Bi nanosheets (Zn–Bi NSs) as a highly active and robust catalyst for electrochemical reduction of CO2 to formate. Specifically, the Zn–Bi NS catalyst can be obtained using a hydrothermal method to prepare a Zn-decorated Bi2O2CO3 nanosheet followed by electrochemical reduction treatment. The as-prepared catalyst exhibits a remarkable formate faradaic efficiency of 94.6% and a high formate current density of 40.5 mA cm−2 at −1.2 V vs. reversible hydrogen electrode (RHE). In particular, the faradaic efficiency of formate remained at above 90% over a wide potential window from −0.8 to −1.2 V vs. RHE. In the H-type electrolytic cell, the Zn–Bi NS catalyst can be operated stably for 10 h at a cathode potential of −1.0 V vs. RHE with good retention of the physical phase. [ABSTRACT FROM AUTHOR]

[Display omitted] The zinc-air battery (ZAB) performance and stability strongly depend on the structure of bifunctional electrocatalyst for oxygen reduction/evolution reaction (ORR/OER). In this work, we combine the tip and heterogeneous effects to construct cobalt/cobalt oxide heterostructure nanoarrays (Co/CoO-NAs). Due to the formed heterostructure, more oxygen vacancies are found for Co/CoO-NAs resulting in a 1.4-fold higher ORR intrinsic activity than commercial carbon supported platinum electrocatalyst (Pt/C) at 0.8 V versus reversible hydrogen electrode (vs. RHE). Moreover, a fast surface reconstruction is observed for Co/CoO-NAs during OER catalysis evidenced by in-situ electrochemical impedance spectroscopy and Raman tests. In addition, the tip effect efficiently lowers the mass transfer resistance triggering a low overpotential of 347 mV at 200 mA cm−2 for Co/CoO-NAs. The strong electronic interplay between cobalt (Co) and cobalt oxide (CoO) contributes to a stable battery performance during 1200 h galvanostatic charge–discharge test at 5 mA cm−2. This work offers a new avenue to construct high-performance and stable oxygen electrocatalyst for rechargeable ZAB. [ABSTRACT FROM AUTHOR]

A novel porous Ni matrix with optimal pore structure and adequate mechanical property is successfully prepared by a modified spark plasma sintering progress, while a self-supporting HER electrode of Ni 3 Se 2 @Porous Ni is subsequently obtained via a facile one-step hydrothermal synthesis. Such the Ni 3 Se 2 @Porous Ni electrode has performed a superior conductivity, excellent catalytic activity and robust durability, which can be attributed to the strong covalent bonding between Ni 3 Se 2 and Ni matrix, abundant active sites of the vertically arranged nanosheets, as well as the metallurgically bonded metal skeleton, exhibiting a fascinating potential for the industrial application. [Display omitted] Developing efficient and durable self-supporting catalytic electrodes is an important way for industrial applications of hydrogen evolution reaction. Currently, commercial nickel foam (NF)-based electrode has been widely used due to its good catalytic performance. However, the NF consisting of smooth skeleton surface and large pores not only exhibits poor conductivity but also provides insufficient space for catalyst decoration and sufficient adhesion, resulting in inadequate catalytic performance and poor durability of NF-based electrodes. In this paper, a novel three-dimensional porous Ni substrate with multangular skeleton surface and small pore structure was prepared by a modified spark plasma sintering technique, and subsequently Ni 3 Se 2 @Porous Ni electrode with a large number of Ni 3 Se 2 nanosheets uniformly distributed on the surface was obtained by one-step in-situ selenization. The electrode exhibits outstanding conductivity and catalytic hydrogen evolution reaction, providing a low overpotential of 183 mV at a current density of 100 mA cm−2. Due to the strong interfacial bonding between Ni and Ni 3 Se 2 , the Ni 3 Se 2 @Porous Ni electrode shows strong durability, which can work stably at 85 mA cm−2 for more than 200 h. This work provides an effective strategy for the rational preparation of metal substrates for efficient and durable self-supporting catalytic electrodes. [ABSTRACT FROM AUTHOR]

Flexible pH sensors have attracted a great deal of attention in numerous applications, such as wearable healthcare devices, smart wound bandages, and other pH monitor sensors for chemical and bioprocess control. Herein, a facile approach to fabricate conducting polymer polypyrrole nanopillar arrays is proposed, and its potential as an advanced pH sensing interface is shown. Using oxygen plasma treatment as the etching tool, polypyrrole nanopillar/hair arrays can be prepared after etching 3D polypyrrole network structures. Conductive polypyrrole nanopillar arrays possessed unique advantages in sensing: their featured nanopillars has enhanced antibacterial properties; their structures showed excellent hydrophilicity and are favorable for interaction with analytes in small‐volume liquids. A flexible polypyrrole nanopillar array‐based potentiometric pH sensor integrated with a solid‐state reference electrode is further designed and fabricated. Superior performance with a near‐Nernstian response of 60.1±1.0 mV pH−1, excellent repeatability, high stability, and reproducibility is verified in the physiological pH range. The reliabilities of flexible and small‐volume sample testing, as well as the applicability for artificial sweat sample pH sensing, are examined. Provided with the advantages of antibacterial properties and hydrophilicity, the proposed flexible pH sensor is promising for trace analysis in biological, medical, and healthcare applications. [ABSTRACT FROM AUTHOR]

Cu2O has emerged as a promising material for sustainable hydrogen production through photoelectrochemical (PEC) water splitting, while inefficient charge separation remains one of the main challenges hindering its development. In this work, a new architecture of InAlN/Cu2O heterojunction photocathode is demonstrated by combining n‐type InAlN and p‐type Cu2O to improve the charge separation efficiency, thus enhancing PEC water‐splitting performance. The Pt/InAlN/Cu2O photoelectrode exhibits a photocurrent density of 2.54 mA cm−2 at 0 V versus reversible hydrogen electrode (VRHE), which is 3.21 times higher than that of Cu2O (0.79 mA cm−2 at VRHE). The enhanced PEC performance is explained by the larger built‐in potential Vbi of 1.43 V formed at the InAlN/Cu2O p–n junction than that in the single Cu2O photocathode (Vbi < 0.77 V), which improves the separation of the photogenerated carriers and thus relieves the bottlenecks of charge‐transfer kinetics at the electrode bulk and electrode/electrolyte interface. In this work, an avenue is opened for designing III‐nitrides/Cu2O heterojunction toward solar energy conversion. [ABSTRACT FROM AUTHOR]

Heteroatom doping can tune the band structure of semiconductors and enhance their carrier transfer capacity for improving the performance of photoelectrochemical water oxidation. Nevertheless, the introduction of dopants is not always beneficial. In this study, magnesium (Mg) is adopted to dope ZnIn2S4 nanosheet array photoanodes to form a type‐II band structure and reduce bulk recombination, but concurrently introduced deleterious oxygen (O) defects slow down the surface catalytic reaction kinetics. Furthermore, a facile heat treatment strategy is proposed to transform these O defects into Mg─O bonds. First‐principles calculations and electrochemical characterization indicate that the presence of Mg─O bonds provides abundant active sites and efficiently accelerates the surface oxygen evolution reaction by precisely realigning the rate‐determining step from OH* to O* (step 2) to OOH* to O2 (step 4), thereby retarding charge trapping and recombination. As a result, such a photoanode achieves a remarkable performance with a photocurrent as high as 4.91 mA cm−2 at 1.23 V versus reversible hydrogen electrode, and the onset potential shifts negatively about 340 mV. This work provides a new defect modulation idea for converting detrimental defects to favorable ones, and it can be expected to have wide applications in the fields of energy, catalysis, and optoelectronics, etc. [ABSTRACT FROM AUTHOR]

Urea oxidation reaction (UOR) has garnered significant attention in recent years as a promising and sustainable clean‐energy technology. Urea‐containing wastewater poses severe threats to the environment and human health. Numerous studies hence focus on developing UOR as a viable process for simultaneously remediating wastewater and converting it into energy. Moreover, UOR, which has a thermodynamic potential of 0.37 V (vs reversible hydrogen electrode, RHE), shows great promise in replacing the energy‐intensive oxygen evolution reaction (OER; 1.23 V vs RHE). The versatility and stability of urea, particularly at ambient temperatures, make it an attractive alternative to hydrogen in fuel cells. Since UOR entails a complex intermediate adsorption/desorption process, many studies are devoted to designing cost‐effective and efficient catalysts. Notably, transition metal‐based materials with regulated d orbitals have demonstrated significant potential for the UOR process. However, comprehensive reviews focusing on transition metal‐based catalysts remain scarce. In light of this, the review aims to bridge the gap by offering an in‐depth and systematic overview of cutting‐edge design strategies for transition metal‐based catalysts and their diverse applications in UOR. Additionally, the review delves into the status quo and future directions, charting the course for further advancements in this exciting field. [ABSTRACT FROM AUTHOR]

Achieving a high current density during electrochemical overall water splitting is a promising strategy for industrial energy conversion. The mass diffusion rate of OH− ions from the electrolyte to the interfacial active sites strongly influences the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, the delayed‐release of OH− ions modulated by a proper organic polymer membrane on the electrode surface can optimize the OH− accessibility to the active sites (as indicated by the molecular dynamics simulations) is demonstrated and that van der Waals interaction force modulates the OH− residence time in the reaction system. The remarkable performance of the membrane‐modified electrode is achieved at ultra‐high current densities of 1.9 A cm−2 (with an HER overpotential of 602 mV) and 2 A cm−2 (with an OER overpotential of 459 mV) in 1 M KOH solution. Consequently, a super‐high current density of 1.3 A cm−2 is obtained for overall water splitting (at a voltage of only 2.2 V), which is 1.9‐fold higher than that of a benchmarked Pt/C‐IrO2 (684 mA cm−2). Therefore, the delayed‐release of OH− has optimized the mass conversion efficiency of the active sites, thus improving the electrochemical performance of overall water splitting. [ABSTRACT FROM AUTHOR]

The article explores the potential of using uranyl(VI) oxygen to initiate C-H activation through hydrophobic interaction. The authors conducted experiments using bovine serum albumin (BSA) and amino acids to demonstrate the ability of uranyl(VI) to cleave C-H bonds. Molecular dynamics simulations were also used to analyze the interaction between uranyl(VI) and BSA, revealing that uranyl(VI) can bind to BSA without causing significant changes in its structure. The study suggests that uranyl(VI) could serve as a sustainable catalyst for C-H activation. Additionally, the article discusses the binding of uranyl(VI) ions to a protein called bovine serum albumin (BSA), highlighting the specific residues involved in the binding process. This unique binding pattern may have implications for uranyl photocatalysis and the environmental impact of uranium. The study received support from the Japan Society for the Promotion of Science. [Extracted from the article]

Intense pulsed light was investigated for partial photoreduction of AgCl in a poly(vinyl butyral) matrix to obtain a Ag/AgCl reference membrane. The membrane was deposited on both glassy carbon and inkjet‐printed silver electrodes giving all‐solid‐state reference electrodes. Regardless of the electrode material, a sufficient potential stability was obtained in a broad concentration range of various salt solutions. Long‐term potential stability was significantly improved with inkjet‐printed silver electrical contacts. The electroanalytical performance of inkjet‐printed electrodes was successfully demonstrated in potentiometric and amperometric systems. [ABSTRACT FROM AUTHOR]

Promising metal hydride electrode performance of LaNi4.5Co0.4Al0.1, prepared by induction melting and next hydrogen-induced decrepitation, was proven in the present study. Both the composition and microstructure of the electrode material were found to be responsible for its reliable hydrogen capacity and cycle stability. After prolonged exposure to air, the alloys retain their high hydrogen sorption characteristics, revealing only 10% capacity reduction. The gas phase hydriding of the alloys confirms the hydrogen capacity obtained under electrochemical conditions. Furthermore, the influence of C, Co, and Co3O4 additions to the LaNi5-based alloy on the hydrogen electrode performance was also elucidated. The highest capacity of 300 mAh g−1, remaining constant for 20 cycles, was obtained for LaNi4.5Co0.4Al0.1 + 15 mg Co3O4. This material maintains excellent capacity also at high current densities, making it a suitable electrode material in Ni/MH batteries. [ABSTRACT FROM AUTHOR]

The oxidation of carbon in conventional gas diffusion electrodes is a limiting factor for the life of secondary metal-air batteries. Replacement of carbon with zeolite is a possible solution to avoid its oxidation in the gas-diffusion electrodes (GDE) and thus to increase the battery lifetime. Due to the fact that the technology provides the required number of charge/discharge cycles, it is applicable for solar energy storage. Zeolites are a large group of natural or synthetic porous aluminosilicate minerals. Their porous structure provides good gas permeability. The gas diffusion layer of the electrode must also have good hydrophobicity. To prevent leakage of electrolyte from the battery, the zeolite was mixed with an appropriate amount of polytetrafluoroethylene, and the electrode was subjected to hot pressing according to a specially developed procedure. The experiments were performed in a specially designed test cell. Its construction ensures measurements of the bifunctional gas-diffusion electrode in a half-cell configuration applying a reference hydrogen electrode. The stationary volt-ampere characteristics and impedance tests were performed on the zeolite electrodes at certain operating points. The cell was subjected to cycling at charge/discharge current ± 2 mA/cm2, respectively. The obtained experimental results show that zeolite is a suitable material for carbon substitution in secondary metal air batteries. The zeolite/polytetrafluoroethylene (PTFE) ratio needs to be optimised in order to improve the gas permeability of the gas diffusion layer without compromising hydrophobicity. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4) is reported as a key material in photoelectrocatalysis owing to high theoretical efficiency, relatively narrow band gap of 2.4 eV, and favorable conduction band edge position for hydrogen evolution. However, the sluggish hole transport dynamics lead to slow photogenerated charge separation and transport efficiencies, which result in charge recombination due to aggregation. Herein, a novel hole transport layer of copper(I) thiocyanate (CuSCN) with the aim of significantly enhancing the efficiency of charge transport and stability of BiVO4 photoanodes is reported. The introduction of the hole transport layer could provide an appropriate intermediate energy level for photogenerated hole transfer and avoid charge recombination and trapping. After a photoassisted electrodeposition process of NiCoFe‐Bi catalysis, the obtained photoanode achieves a photocurrent density of 5.6 mA cm−2 at 1.23 V versus reversible hydrogen electrode under AM 1.5 G simulated solar radiation, and an applied bias photon to current efficiency of 2.31%. With the CuSCN layer, BiVO4 photoanode presented impressive stable photocurrent during 50 h continuous illumination. Meanwhile, the unbiased tandem device of the NiCoFe‐Bi/CuSCN/BiVO4 photoanode and the Si solar cell exhibit a solar‐to‐hydrogen efficiency of 5.75% and excellent stability for 14 h. [ABSTRACT FROM AUTHOR]

Introduction: A new analytical method based on the coupling of microextraction and microfluidics was developed and investigated for the pre-concentration, separation, and electrochemical detection of fenitrothion (FT) and parathion (PA) at the sub-ppm concentrations. Methods: In the first step, the microchip capillary electrophoresis technique was used to serve as a separation and detection system. Analytes were injected in the 40 mm long microchannel with 10 mm sidearms. Then, they were separated by applying a direct electrical field (+1800 V) between the buffer and detection reservoirs. 2-(n-morpholino)ethanesulfonic acid (MES) buffer (20 mM, pH 5) was used as a running buffer. The electrochemical detection was performed using three Pt microelectrodes with the width of working, counter, and reference electrodes (50, 250, and 250 µm, respectively) in the out-channel approach. Results: The system was devised to have the optimum detection potential equal to -1.2 V vs. pseudo-reference electrode. The dimensions of the SU-8 channel have 20 µm depth and 50 µm width. In the second step, an air-assisted liquid-liquid microextraction technique was used to extract and preconcentration of analytes from human blood plasma. Then, 1, 2 di-bromoethan was used as extractant solvent, the analytes were preconcentrated, and the sedimented solvent (50 µL) was evaporated in a 60 °C water bath followed by substitution of running buffer containing 10% ethanol. The optimal extraction cycles were found to be 8 with adding 1% NaCl to the aqueous phase. Analyzing time of the mentioned analytes was less than 100s, the precision range was 3.3 - 8.2 with a linear range of 0.8-100 ppm and 1.2-100 ppm for FT and PA, respectively. The extraction recoveries were about 91% and 87% for FT and PA, respectively. The detection limits for FT and PA were 240 and 360 ppb, respectively. Finally, the reliability of the method was investigated by GC-FID. Conclusion: The proposed method and device were validated and can be used as in situ and portable detection systems for detecting fenitrothion and parathion insecticides. [ABSTRACT FROM AUTHOR]

Highlights: What are the main findings? Square-wave power has the greatest influence on Ni cathode HER compared to step- and triangle-power. Increasing the amplitude of square-wave power enhances coated cathode's degradation. What is the implication of the main finding? Guidance for industrializing hydrogen production via renewable energy-coupled electrolytic water. Evaluation theory of cathode materials in electrolytic water. The combination of water electrolysis and renewable energy to produce hydrogen is a promising way to solve the climate and energy crisis. However, the fluctuating characteristics of renewable energy not only present a significant challenge to the use of water electrolysis electrodes, but also limit the development of the hydrogen production industry. In this study, the effects of three different types of waveforms (square, step, and triangle, which were used to simulate the power input of renewable energy) on the electrochemical catalysis behavior of Ni plate cathodes for HER was investigated. During the test, the HER performance of the Ni cathode increased at first and then slightly decreased. The fluctuating power led to the degradation of the Ni cathode surface, which enhanced the catalysis effect by increasing the catalytic area and the active sites. However, prolonged operation under power fluctuations could have damaged the morphology of the electrode surface and the substances comprising this surface, potentially resulting in a decline in catalytic efficiency. In addition, the electrochemical catalysis behavior of the prepared FeNiMo-LDH@NiMo/SS cathode when subjected to square-wave potential with different fluctuation amplitudes was also extensively studied. A larger amplitude of fluctuating power led to a change in the overpotential and stability of the LDH electrode, which accelerated the degradation of the cathode. This research provides a technological basis for the coupling of water electrolysis and fluctuating renewable energy and thus offers assistance to the development of the "green hydrogen" industry. [ABSTRACT FROM AUTHOR]

Oxygen reduction reaction (ORR) is an important reaction process that occurs at the cathode of zinc-air batteries. An efficient reaction process is conducive to further research on sustainable energy devices. In order to improve the reaction speed, the ORR electrocatalyst containing uniform Fe–N-C sites in a porous carbon network similar to the shape of moth-eaten rotten wood was prepared using water hyacinth with a thin-layer structure inside as a template. Water hyacinth, plays a variety of synthetic functions in the construction of nanocatalysts, not only has a good enrichment effect on metal elements, but also is rich in N element. The doped Fe elements combine with the carbon and N elements of water hyacinth to form Fe–N-C active sites. The half-wave potential of SHL-Fe-HMNC is raised to 0.881 V (0.838 V for commercial 20wt% Pt/C) compared to the reversible hydrogen electrode (RHE). The power density of the liquid battery prepared based on SHL-Fe-HMNC reaches 110 mW·cm−2 (90 mW·cm−2 for 20 wt% Pt/C). Furthermore, the cycle time of ZABs exceeds 200 h. The flexible battery based on SHL-Fe-HMNC has a cycle stability of more than 10 h at a current of 10 mA·cm−2, and the open circuit voltage (OCV) reaches 1.511 V. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochemical reduction of CO 2 (CO 2 RR) to fuels and chemicals is a promising route to close the anthropogenic carbon cycle for sustainable society. The Cu-based catalysts in producing high-value hydrocarbons feature unique superiorities, yet challenges remain in achieving high selectivity. In this work, Cu@ZIF-8 NWs with highly-exposed Cu nanowires (Cu NWs) and ZIF-8 interface are synthesized via a surfactant-assisted method. Impressively, Cu@ZIF-8 NWs exhibit excellent stability and a high Faradaic efficiency of 57.5% toward hydrocarbons (CH 4 and C 2 H 4) at a potential of −0.7 V versus reversible hydrogen electrode. Computational calculations combining with experiments reveal the formation of Cu and ZIF-8 interface optimizes the adsorption of reaction intermediates, particularly stabilizing the formation of *CHO, thereby enabling efficient preference for hydrocarbons. This work highlights the potential of constructing metals and MOFs heterogeneous interfaces to enhance catalytic properties and offers valuable insights for the design of highly efficient CO 2 RR catalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] The use of low-cost and effective cocatalyst is a potential strategy to optimize the effectiveness of photoelectrochemical (PEC) water splitting. In this study, tungsten phosphide (WP) is introduced as a remarkably active cocatalyst to enhance the PEC efficiency of a Bi 2 WO 6 photoanode. The onset potential of Bi 2 WO 6 /WP demonstrates a negative shift, while the photocurrent density demonstrates a significant 5.5-fold increase compared to that of unmodified Bi 2 WO 6 at 1.23 V RHE (reversible hydrogen electrode). The loading of WP cocatalyst facilitates the rapid transfer of holes, increasing the range of visible light absorption, the water adsorption ability as well as promoting the separation of photogenerated electrons and holes via the built-in electric field between Bi 2 WO 6 and WP. This study proposes a strategy to hinder the recombination of electron-hole pairs by using WP cocatalyst as a hole capture agent, improve the photoelectric conversion efficiency, and enhance the overall photoelectrochemical properties of Bi 2 WO 6 photoanode. [ABSTRACT FROM AUTHOR]

[Display omitted] The Cu0-Cu+ interfaces play a key role in the electrochemical CO 2 reduction reaction (CO 2 RR) to produce multi-carbon products (C 2+), however, it is difficult for Cu+ to exist stably under reducing conditions. Herein, we construct highly dispersed and stable Cu-Cu 2 O-CeO x interface on reduced graphene oxide (rGO) for CO 2 electroreduction to C 2+ products. During the synthesis process, utilizing strong electrostatic interactions, the complex ions of Cu2+ and Ce3+ are uniformly adsorbed on the surface of graphene oxide. Then, under the solvothermal reaction of ethylene glycol and thiourea, the two metal complex ions are converted into highly dispersed and ultrafine Cu 2 S-CeO x nanocomposites on rGO. Interestingly, CeO x and thiourea synergistically regulate the generation of only Cu+. Under the CO 2 RR process, the reconstruction of Cu 2 S promotes the formation of Cu0 and Cu 2 O species. CeO x stabilizes partial Cu+ species and promotes the formation of Cu-Cu 2 O-CeO x composite interface. With the help of synergistic effect of Cu0, Cu+ and CeO x , the optimized reaction interface achieves the Faradaic efficiency (FE) of 74.5 % for C 2+ products with the current density of 230 mA cm−2 at −0.9 V versus the reversible hydrogen electrode. In situ attenuate total reflectance-infrared absorption spectroscopy (ATR-IRAS) spectra show that the composite interfaces promote the adsorption and activation of H 2 O and CO 2 , improve the surface coverage of CO intermediates (*CO), and thus accelerate the C C coupling process. [ABSTRACT FROM AUTHOR]

[Display omitted] The controlled cation substitution is an effective strategy for optimizing the density of states and enhancing the electrocatalytic activity of transition metal oxide catalysts for water splitting. However, achieving tailored mesoporosity while maintaining elemental homogeneity and phase purity remains a significant challenge, especially when aiming for complex multi-metal oxides. In this study, we utilized a one-step impregnation nanocasting method for synthesizing mesoporous Mn-, Fe-, and Ni-substituted cobalt spinel oxide (Mn 0.1 Fe 0.1 Ni 0.3 Co 2.5 O 4 , MFNCO) and demonstrate the benefits of low-temperature calcination within a semi-sealed container at 150–200 °C. The comprehensive discussion of calcination temperature effects on porosity, particle size, surface chemistry and catalytic performance for the alkaline oxygen evolution reaction (OER) highlights the importance of humidity, which was modulated by a pre-drying step. The catalyst calcined at 170 °C exhibited the lowest overpotential (335 mV at 10 mA cm−2), highest current density (433 mA cm−2 at 1.7 V vs. RHE, reversible hydrogen electrode) and further displayed excellent stability over 22 h (at 10 mA cm−2). Furthermore, we successfully adapted this method to utilize cheap, commercially available silica gel as a hard template, yielding comparable OER performance. Our results represent a significant progress in the cost-efficient large-scale preparation of complex multi-metal oxides for catalytic applications. [ABSTRACT FROM AUTHOR]

The paper presents an original method for synthesizing high-density composite ceramics with a Mo 2 C/Mo 3 Co 3 C composition using the technology of high-speed Spark Plasma Sintering (SPS) of a mechanically activated powder mixture of Mo 2 C-10 wt%Co. The activated homogeneous starting mixture was obtained by wet milling/activation of the initial powders of Mo 2 C and Co in an anhydrous isopropanol medium. The ceramic samples were consolidated by SPS under vacuum (10−5 atm.) at 1000, 1100, 1150, and 1200 °C with a heating rate of 87.3 °C·min−1 under constant external uniaxial pressing pressure of 50 MPa. The sintering kinetics were studied, the twofold nature of sintering was established, and the temperature range of active densification was determined. The ceramic synthesis is accompanied by a reactive interaction of the components, resulting in the formation of the Mo 3 Co 3 C phase and a change in the crystal lattice of the non-stoichiometric Mo 2 C x compound. The ceramic obtained in the temperature interval of the isothermal sintering stage of 1150–1200 °C is homogeneous in the distribution of Mo and Co, consists of a Mo 2 C/Mo 3 Co 3 C phase mixture, has a density value of 98.13 ± 0.5 % theoretical density, and has an average Vickers hardness value of ∼1526 HV. Increasing the sintering temperature to 1200 °C results in the formation of almost monolithic structures in the samples, but also induces the formation of large defects due to the collective consolidation of pores within the bulk material and increases the susceptibility of the ceramic to cracking. The paper presents preliminary results from electrochemical testing. The proposed method for synthesizing Mo 2 C/Mo 3 Co 3 C ceramics has potential for use in optimizing the composition and production methods of electrode materials for the realization of active components in heterostructured electrodes used for hydrogen evolution. [ABSTRACT FROM AUTHOR]

A series of isostructural Co/Ni-MOFs with different linearly bridged bipyridines as organic linkers has been designed and synthesized. Experimental studies reveal that linker engineering by tuning the functional block of the pyridine-bridging units renders these MOFs derived materials with significantly improved electrocatalytic nitrogen reduction reactions (eNRR) to NH 3. Among them, at −0.4 V vs reversible hydrogen electrode the one containing a 1,3,4-thiadiazole unit exhibits the best eNRR performance in 0.1 M Na 2 SO 4 with the highest NH 3 yield (39.7 μg h−1 mg−1) and Faraday efficiency (33.3 %). This excellent nitrogen fixation performance comes from the synergistic effect of the heterojunction formed by the Co 2 N component that is conducive to nitrogen fixation and the Co 9 S 8 component that inhibits hydrogen evolution in the derived material. Significantly, the systematic tuning of the bridging ligands in MOFs provides a new pathway to develop eNRR electrocatalysts. By tuning the functional block of the pyridine-bridging units renders these MOFs derived materials with significantly improved electrocatalytic nitrogen reduction reactions to NH 3. [Display omitted] • Six isostructural Co/Ni-MOFs with different ligands were designed and synthesized. • Tuning the functional block of catalysts improves nitrogen fixation property. • The Co-dpt-hfipbb-800 catalyst exhibits the highest NH 3 yield of 39.7 μg h−1 mg−1. • The synergistic effect of the heterojunction is conducive to nitrogen fixation. [ABSTRACT FROM AUTHOR]

Single atom catalysts (SACs) play a crucial role in energy catalysis due to their distinct coordination environment and high atomic utilization efficiency. This study focuses on the synthesis of a monatomic Cu catalyst with Cu-N1C1 coordination anchored to N-doped Ti3C2Tx MXene (Cu SA@N-Ti3C2Tx) to achieve efficient reduction of CO2 to CO. Detailed characterization, including morphology and multispectral analysis, confirmed the uniform distribution of asymmetrically coordinated Cu atoms in unsaturated C-Cu-N bridge fragments on Ti3C2Tx. The Cu SA@N-Ti3C2Tx catalyst exhibited an excellent CO selectivity with Faraday efficiency of 97.4% at −0.58 V vs. reversible hydrogen electrode (RHE) and satisfactory durability. The in situ X-ray absorption fine structure (XAFS) results confirmed that the carbon dioxide reduction reaction (CO2RR) product distribution is mainly affected by potential-dependent valence change of Cu species. These findings highlight the extensive potential of tuning coordination structure of MXene-based single-atom catalysts for CO2 reduction reactions. [ABSTRACT FROM AUTHOR]

Electrochemical nitrate reduction reaction (NO3RR) towards ammonia, as an emerging and appealing technology alternative to the energy-intensive Haber–Bosch process and inefficient nitrogen reduction reaction, has recently aroused wide concern and research. However, the current research of the NO3RR towards ammonia lacks the overall performance comparison of various electrocatalysts. Given this, we here make a comparison of 12 common transition metal oxide catalysts for the NO3RR under a high cathodic current density of 0.25 A·cm−2, wherein Co3O4 catalyst displays the highest ammonia Faradaic efficiency (85.15%) and moderate activity (ca. −0.25 V vs. reversible hydrogen electrode). Other external factors, such as nitrate concentrations in the electrolyte and applied potential ranges, have also been specifically investigated for the NO3RR. [ABSTRACT FROM AUTHOR]

The electrochemical CO2 reduction reaction (CO2RR) has received widespread attention as a promising method for producing sustainable chemicals and mitigating the global warming. Here, we demonstrate a general and facile synthetic route for the metal-nitrogen-carbon (M-N-C) type catalyst by simply calcinating metal acetate and urea with commercial carbon black, which have potential application in CO2RR. The synthesized Ni−NC−600 catalyst has the structure of single Ni atom coordinated with one N atom and three C atoms (Ni−N1C3), which is suggested by X-ray absorption spectroscopy. The Ni−NC−600 catalyst exhibits high CO2RR catalytic performance and a high CO Faraday efficiency above 98% in a wide potential range from −0.7 to −1.3 V (vs. reversible hydrogen electrode (RHE)), superior to most of the reported Ni−N−C catalysts. This work has developed a facile strategy to synthesize high performance CO2RR catalyst. [ABSTRACT FROM AUTHOR]

The efficiency of water electrolysis is significantly affected by the bubbles on the surface and inside the electrode. To enhance the gas–liquid transfer within the porous electrodes, we developed an innovative design termed dual-aligned porous electrode (D-APE), achieved by integrating magnetic alignment with freeze casting techniques. This paper investigates the hydrogen evolution performance of porous electrodes prepared using four different methods: evaporation, magnetic-aligned evaporation, freeze casting, and dual-aligned methods. The findings demonstrate that the magnetic-aligned process effectively alters the electrode structure, resulting in improved hydrogen evolution performance. Notably, among all the examined electrodes, the D-APE exhibits the highest hydrogen evolution performance, with further enhancements observed with prolonged the time of magnetic alignment. Furthermore, a comparison is made between electrodes prepared using the freeze casting method and the dual-aligned method at various thickness. The results show that the thinner D-APE exhibits excellent hydrogen evolution performance at high current density. Moreover, the D-APE demonstrates significantly improved material utilization rates compared to the conventional freeze casting method, offering promising prospects for enhancing the efficiency of water electrolysis. [ABSTRACT FROM AUTHOR]

Effective electrochemical conversion of CO2 to value-added liquid multi-carbon products driven by renewable energy is a promising approach to alleviate excessive CO2 emission and achieve large-scale renewable energy storage. However, the selectivity and catalytic activity towards liquid multi-carbon products of CO2 electroreduction reaction are still unsatisfactory due to the sluggish C–C coupling process and the formation of complex oxygen-containing intermediates. Hence, designing and fabricating highly effective electrocatalysts is crucial for practical applications in this field. Here, we developed Cl-modified Cu catalyst (Cu-Cl) for efficient electrochemical reduction of CO2 to ethanol. The optimal Faradaic efficiency and partial current density of ethanol on the Cu-Cl sample reached 26.2% and 343.2 mA·cm−2 at −0.74 V (vs. reversible hydrogen electrode (RHE)), which were 1.66 and 1.76 times higher than those of the catalyst without Cl decoration, outperforming those in most previously reported works. Density functional theory (DFT) calculations revealed that the Cl-modified Cu surface suppressed the parasitic hydrogen evolution reaction (HER) and reduced the energy barrier for the C–C coupling process, making the formation of key intermediates favorable for ethanol production. Thus, the decoration of Cl on the Cu surface facilitated ethanol formation. [ABSTRACT FROM AUTHOR]

Regulating the electronic structure of Bi-based materials by alloying engineering is promising to promote the electrocatalytic activity, but it remains some challenges to be solved. In this study, a facile electrochemical co-deposition strategy is developed to synthesize the bimetallic Bi9Cu1 alloy nanosheet on carbon cloth (Bi9Cu1/CC), which represents a novel self-supporting electrode for the electrocatalytic carbon dioxide (CO2) reduction reaction (CO2RR). The Bi9Cu1/CC catalyst has achieved a remarkable catalytic performance with high Faradaic efficiencies (FE) of over 90% for formate at wide potentials from −0.7 to −1.2 V vs. reversible hydrogen electrode (RHE). Moreover, the reversible Zn-CO2 battery can be driven by Bi9Cu1/CC cathode with a largest power density of 1.4 mW·cm−2, and superior operating stability. The systematic characterizations and electrochemical results confirm that the improved catalytic active sites, the enhanced mass/charge transport and the optimal reaction kinetics of Bi nanosheet are realized for CO2RR by Cu alloying. In situ attenuated total reflection infrared (ATR-IR) result confirms the bimetallic Bi-Cu active sites prefer to follow the ⋆OCHO conversion pathway. The density functional theory (DFT) calculations suggest that the Cu alloying contributes to the increased density of states near the Fermi surface of Bi and the optimized adsorption of ⋆OCHO intermediates on the Bi sites, resulting in the excellent catalytic performance. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4) is a promising photoanode material for efficient photoelectrochemical (PEC) water splitting, whereas its performance is inhibited by detrimental surface states. To solve the problem, herein, a low-cost organic molecule 1,3,5-benzenetricarboxylic acid (BTC) is selected for surface passivation of BiVO4 photoanodes (BVOs), which also provides bonding sites for Co2+ to anchor, resulting in a Co-BTC-BVO photoanode. Owing to its strong coordination with metal ions, BTC not only passivates surface states of BVO, but also provides bonding between BVO and catalytic active sites (Co2+) to form a molecular cocatalyst. Computational study and interfacial charge kinetic investigation reveal that chemical bonding formed at the interface greatly suppresses charge recombination and accelerates charge transfer. The obtained Co-BTC-BVO photoanode exhibits a photocurrent density of 4.82 mA/cm2 at 1.23 V vs. reversible hydrogen electrode (RHE) and a low onset potential of 0.22 VRHE under AM 1.5 G illumination, which ranks among the best photoanodes coupled with Co-based cocatalysts. This work presents a novel selection of passivation layers and emphasizes the significance of interfacial chemical bonding for the construction of efficient photoanodes. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2 reduction reaction (ECO2RR) converts CO2 to high-value chemical products and promotes the carbon cycle. Sulfur (S)-modified copper (Cu) and bismuth (Bi)-based catalysts have been recognized as promising catalysts for ECO2RR. Both of them are highly active for selective formate generation, however, their poor stability and severe competing hydrogen evolution reaction (HER) remain challenging. Herein, S-doped Cu coated with Bi (Bi/Cu-S) is developed to improve ECO2RR selectivity to formate. Bi/Cu-S/brass mesh (BM) electrode material for ECO2RR was prepared by electrodepositing Bi on the surface of Cu-S/BM nanowires obtained from CuS/BM after the electroreduction. The Faradaic efficiency (FE) of the formate reaches the maximum of 94.3% at −0.9 V vs. reversible hydrogen electrode (RHE) with a partial current density as high as −50.7 mAcm−2 and a yield of 30.7 mmolh−1cm−2 under 0.5 M KHCO3 electrolyte. Meanwhile, the FE of formate is higher than 90% in the voltage range of −0.8 to −1.0 V vs. RHE. It also shows good stability at −0.9 V vs. RHE with the FE of formate remaining above 93% after a 10 h reaction. Density functional theory (DFT) calculations demonstrate that the Bi/Cu-S structure promotes the adsorption of CO2 and effectively inhibits HER by enhancing the adsorption of *H to a great extent, improving the selective conversion of CO2 to formate. This work deepens the understanding of the mechanism of Cu-Bi-based catalysts and S-modified Cu-based catalysts in selective ECO2RR to formate, and also provides a new strategy for catalyst design. [ABSTRACT FROM AUTHOR]

Developing high‐performance electrocatalysts for CO2 reduction reaction (CO2RR) is vital in achieving a carbon‐neutral society by converting CO2 into valuable chemicals. CO2RR electrocatalyst with lower overpotential, higher selectivity and wider working potential range is urgently desired, but it is still challenging to realize these factors simultaneously. Here, high‐performance bismuthene‐based electrocatalysts were synthesized by reducing bismuth precursors like BiCl3, BiBr3, and BiI3 in liquid phases. Especially, bismuthene‐I derived from BiI3 showed a nanosheet morphology (around four‐layer) with significantly enhanced (110) surfaces. It enabled an ultrawide potential window (0.7 V) for high formate selectivity (>90%) in a H‐type cell and achieved an ultralow potential (−0.46 V vs. reversible hydrogen electrode) to attain a current density of 200 mA cm−2 in a gas‐diffusion flow cell. The prominent long‐term operational capability of bismuthene‐I was demonstrated in both H‐type and gas‐diffusion cells. Density functional theory calculations revealed that bismuthene‐I possessed abundant topological Bi(110) surfaces states that can reduce the CO2RR overpotential, suppress the competitive hydrogen evolution reaction, and facilitate electron donation during CO2 electrocatalysis. The bismuthene‐I realized low overpotential, high selectivity and wide working potential range simultaneously for electrochemical CO2RR. This work unfolds the broader plausibility of facilely reducing precursors for the scalable fabrication of high‐performing CO2RR electrocatalysts. [ABSTRACT FROM AUTHOR]

Nitrogen electrofixation under ambient conditions is a promising approach to synthesize ammonia sustainably but improving the yield and efficiency remains a challenge. This is due to the competition between the nitrogen electrofixation and hydrogen evolution reactions, which can be depressed through appropriate working electrode design. This study investigated the influence of the catalyst‐binder configuration on ammonia yield and Faradic efficiency. A series of working electrodes were tested in an aqueous system, with the proton and electron transfer on the working electrode found to be dependent on the catalyst material, binder material, and binder hydrophobicity. The use of a binder with low proton/electron conductivity increased Faradic efficiency by hindering the hydrogen evolution reaction and reducing charge transfer to the catalytic material. Utilising a hydrophobic binder significantly improved ammonia yield. Furthermore, nitrogen sorption experiments revealed that the catalyst's nitrogen affinity exerts a greater influence on ammonia yield than the binder's affinity. The best performance was observed for a semi‐conductive catalyst based on vanadium, integrated within a highly hydrophobic perfluorinated binder. At ambient conditions in 0.1 M hydrogen chloride, 39.3±4.3 μgh-1mgcat.-1 ${\mu g{{\rm \ }h}^{-1}{\rm \ }{mg}_{cat.}^{-1}}$ of ammonia was synthesized with 38.5±4.5 % Faradic efficiency at −0.2 V versus a reversible hydrogen electrode. [ABSTRACT FROM AUTHOR]

Despite the coexistence of CO and H2S in reformed hydrogen, studies on the interaction between impurities are lacking. In this study, the co‐poisoning effect of CO and H2S on a polymer electrolyte membrane fuel cell (PEMFC) is systematically investigated using a hydrogen reference electrode inserted into a membrane electrode assembly (MEA). Notably, when CO and H2S are present simultaneously, the poisoning rate is accelerated and is higher than the simple sum of the poisoning by the individual gases, suggesting a complex synergic effect between the two gases. This phenomenon can be attributed to the potential‐dependent behavior of H2S poisoning, whereas CO poisoning remains independent of the potential but depends on the total poisoning time. Therefore, the potential of the anode rises over time due to the time‐dependent CO poisoning, which accelerates the potential‐dependent H2S poisoning. As a result, the cell voltage decreases more rapidly in the CO and H2S mixture. [ABSTRACT FROM AUTHOR]

Metal‐organic frameworks recently have been burgeoning and used as precursors to obtain various metal–nitrogen–carbon catalysts for oxygen reduction reaction (ORR). Although rarely studied, Mn–N–C is a promising catalyst for ORR due to its weak Fenton reaction activity and strong graphitization catalysis. Here, we developed a facile strategy for anchoring the atomically dispersed nitrogen‐coordinated single Mn sites on carbon nanosheets (MnNCS) from an Mn‐hexamine coordination framework. The atomically dispersed Mn–N4 sites were dispersed on ultrathin carbon nanosheets with a hierarchically porous structure. The optimized MnNCS displayed an excellent ORR performance in half‐cells (0.89 V vs. reversible hydrogen electrode (RHE) in base and 0.76 V vs. RHE in acid in half‐wave potential) and Zn–air batteries (233 mW cm−2 in peak power density), along with significantly enhanced stability. Density functional theory calculations further corroborated that the Mn–N4–C12 site has favorable adsorption of *OH as the rate‐determining step. These findings demonstrate that the metal‐hexamine coordination framework can be used as a model system for the rational design of highly active atomic metal catalysts for energy applications. [ABSTRACT FROM AUTHOR]

Electrocatalytic CO2‐to‐formate conversion is considered an economically viable process. In general, Zn‐based nanomaterials are well‐known to be highly efficient electrocatalysts for the conversion of CO2 to CO, but seldom do they exhibit excellent selectivity toward formate. In this article, we demonstrate that a heterointerface catalyst ZnO/ZnSnO3 with nanosheet morphology shows enhanced selectivity with a maximum Faradaic efficiency (FE) of 86% at −0.9 V versus reversible hydrogen electrode and larger current density for the conversion of CO2 to formate than pristine ZnO and ZnSnO3. In particular, the FEs of the C1 products (CO + HCOO−) exceed 98% over the potential window. The experimental measurements combined with theoretical calculations revealed that the ZnO in ZnO/ZnSnO3 heterojunction delivers the valence electron depletion and accordingly optimizes Zn d‐band center, which results in moderate Zn–O hybridization of HCOO* and weakened Zn–C hybridization of competing COOH*, thus greatly boosting the HCOOH generation. Our study highlights the importance of charge redistribution in catalysts on the selectivity of electrochemical CO2 reduction. [ABSTRACT FROM AUTHOR]

Surface platinum hydride structures may exist and play a potentially important role during electrocatalysis and cathodic corrosion of Pt(111). Earlier work on platinum hydrides suggests that Pt may form clusters with multiple equivalents of hydrogen. Here, using thermodynamic methods and density functional theory, we compared several surface hydride structures on Pt(111). The structures contain multiple monolayers of hydrogen in or near the surface Pt layer. The hydrogen in these structures may bind the subsurface or reconstruct the surface both in the set of initial configurations and in the resulting (meta)stable structures. Multilayer stable configurations share one monolayer of subsurface H stacking between the top two Pt layers. The structure containing two monolayers (MLs) of H is formed at −0.29 V vs normal hydrogen electrode, is locally stable with respect to configurations with similar H densities, and binds H neutrally. Structures with 3 and 4 ML H form at −0.36 and −0.44 V, respectively, which correspond reasonably well to the experimental onset potential of cathodic corrosion on Pt(111). For the 3 ML configuration, the top Pt layer is reconstructed by interstitial H atoms to form a well-ordered structure with Pt atoms surrounded by four, five, or six H atoms in roughly square-planar and octahedral coordination patterns. Our work provides insight into the operando surface state during low-potential reduction reactions on Pt(111) and shows a plausible precursor for cathodic corrosion. [ABSTRACT FROM AUTHOR]

Structural modulation of the active site with atomic-level precision is of great importance to meet the activity and selectivity challenges that electrocatalysts are commonly facing. In this work, we have designed a metal (M)–nonmetal diatomic site embedded in graphene-like C2N (denoted as Mo–B@C2N), where the electrocatalytic N2 reduction reaction (eNRR) was thoroughly explored using density functional theory combined with the computational hydrogen electrode method. Compared to M–M diatomic sites, the Mo–B site can generate a pronounced synergistic effect that led to eNRR proceeding via a novel quasi-dissociative reaction mechanism that has not been reported relative to the conventional enzymatic, consecutive, distal, and alternating associative mechanism. This newly uncovered mechanism in which N–N bond scission takes place immediately after the first proton-coupled electron transfer (PCET) step (i.e., *NH–*N + H+ + e− → *NH2*N) has demonstrated much advantage in the PCET process over the four conventional mechanism in terms of thermodynamic barrier, except that the adsorption of side-on *N2 seemed thermodynamically unfavorable (ΔGads = 0.61 eV). Our results have revealed that the activation of the inert N≡N triple bond is dominated by the π*-backdonation mechanism as a consequence of charge transfers from both the B and Mo sites and, unexpectedly, from the substrate C2N itself as well. Moreover, the hybrid Mo–B diatomic site demonstrated superior performance over either the Mo–Mo or B–B site for driving eNRR. Our study could provide insight into the delicate relationships among atomic site, substrate, and electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Revealing the effect of external applied potential on the reaction mechanism and product selectivity is of great significance in electrochemical studies. In this work, the grand canonical density functional theory method was applied to simulate the explicit electrocatalytic process of oxygen evolution reaction and electrochemical ozone production due to the O3 product sensitivity toward the applied potential. Over the Pt/Pd single atom embedded on B/N co-doped graphene (Pt/Pd-BNC) surface, crossover points of O2/O3 selectivity inversion were predicted to be 1.33 and 0.89 V vs standard hydrogen electrode, which were also consistent with the previous experimental results. An in-depth analysis of the energetic terms in the reaction free energies also found the considerable impact of the applied potential on the Helmholtz free energy term, with optimal potential predicted for the key elementary steps, and linear correlations between electrode potential (U) and reaction free energy were found for each elementary step. This study offers extensive knowledge on the potential effect on the O2/O3 selective formation on two-dimensional anode surfaces and provides new insights for investigating the reactivity/selectivity on electrode surfaces in real reaction conditions. [ABSTRACT FROM AUTHOR]

Hierarchical porous carbon materials have received significant attention for application in catalytic water splitting because of their high efficiency, cost-effectiveness, and biocompatibility. In this study, laser-induced graphene (LIG) was fabricated on a carbon film- (CF-) type substrate for an efficient hydrogen evolution reaction (HER). The LIG-CF electrode was fabricated via laser-induced graphitization on a commercial polyimide (PI) film, followed by the pyrolysis of the LIG on the PI film (LIG-PI). During pyrolysis, the microscopic and material properties of the LIG remained intact, as verified through various characterizations. The as-prepared all-carbon electrode was then utilized as an electrode for the HER study in a 1.0 M KOH electrolyte and compared with LIG-PI and Pt electrodes. In the HER experiments, the optimized LIG-CF electrode exhibited excellent catalytic performance with zero-onset potential, and the potentials required to achieve high current densities of 10 and 20 mA/cm2 were 134 and 139 mV (vs. reversible hydrogen electrode (RHE)), respectively. The excellent performance of the LIG-CF electrode originates from the hierarchical porous structure of the LIG material, which serves as an electrochemically active site, and carbon substrate that facilitates the fast transport of ions at the electrode/electrolyte interface. Additionally, the carbon substrate shortens the transportation length of electrons which played a significant role for the enhanced performance of the LIG-CF electrode. [ABSTRACT FROM AUTHOR]

Potassium metal batteries coupling with high-voltage manganese hexacyanoferrate (MnHCF) cathodes are promising candidates for energy storage devices. Ethers are the primary electrolyte solvent candidates for reversible potassium metal anodes, but their poor oxidative stability at high voltage restricts the application. Taking advantage of the steric hindrance, a dilute (1 m) non-fluorinated ether with extended alkyl groups is designed to reduce the solvation capability to K ions, thus suppressing the solvent decomposition and tailoring the interphase composition on both cathode and anode sides. The accompanying high viscosity associated with the long alkyl groups can be readily resolved by incorporating an S-containing additive, which further boosts the oxidative stability to 4.6 V. Furthermore, the additive contributes to the S-rich organic species among the interphases that inhibit the metal dissolution of the cathode and induce the homogenous K deposition through promoted kinetics. Benefiting from the stable interphases and restricted side reactions, the dilute non-fluorinated ether-based electrolyte enables the stable cycling of MnHCF||K cell for over 200 cycles with a high Coulombic efficiency of over 99.4% under a negative/positive capacity ratio of 4. [ABSTRACT FROM AUTHOR]

Aqueous zinc-based energy storage systems (Zn-ESSs) with intrinsic safety and good electrochemical performance are promising power suppliers for flexible electronics, whereas unstable zinc anodes especially in flexible Zn-ESSs pose a challenge. Herein, a self-assembled robust interfacial layer to achieve stable zinc anodes in non-flexible and flexible Zn-ESSs is reported. Specifically, zinc anodes and their slowly-released Zn2+ simultaneously interact with tannic acid molecules in ethanol-water solutions, triggering the self-assembly of a tannic acid/Zn2+ complex interfacial layer (CIL) that firmly anchors on the zinc anodes. The CIL containing abundant carboxyl and phenolic hydroxyl functional groups provides rich zincophilic sites to homogenize Zn2+ flux and accelerate Zn2+ desolvation-deposition, and traps H+/H2O species to prevent them from corroding zinc anodes, thereby stabilizing the zinc deposition interface. Consequently, the CIL@Zn anodes present superior stability with an operation lifetime exceeding 700 h even at 5 mA cm-2 (28 times longer than that of bare zinc anodes) and ultrahigh cumulative plated capacity of ≈1.8 Ah cm-2. The firm anchoring of the CIL enables the CIL@Zn anodes to endure diverse deformations, thus realizing highly flexible CIL@Zn anode-based Zn-ESSs. This work provides thinking in designing stable and flexible zinc anodes, promoting the development of flexible zinc-based energy storage. [ABSTRACT FROM AUTHOR]