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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]

[Display omitted] Electrochemical nitrate reduction to ammonia is a promising alternative strategy for producing valuable ammonia. This prospective route, however, is subject to a slow electrocatalytic rate, which resulted from the weak adsorption and activation of intermediate species, and the low density electron cloud of active centers. To address this issue, we developed a novel approach by doping boron into metal hydroxyl oxides to adjust the electronic structure of active centers, and consequently, led a significant improvement in the Faraday efficiency upto approaching 100 %, as well as an impressive ammonia yield upto approximately 23 mg/h mgcat−1 at −0.6 V vs. reversible hydrogen electrode (RHE). Experimental data in mechanism demonstrate that the doped boron play a crucial role in modulating the local electronic environment surrounding the active sites Co. In situ Raman and FTIR spectra provide evidences that boron facilitates the formation of deoxidation and hydrogenation intermediates. Additionally, density functional theory (DFT) calculations support the notion that boron doping enhances the adsorption capability of intermediates, reduces the reaction barrier, and facilitates the desorption of NH 3. [ABSTRACT FROM AUTHOR]

The electrocatalytic C−N coupling from CO2 and nitrate emerges as one of the solutions for waste upgrading and urea synthesis. In this work, we constructed electron‐deficient Cu sites by the strong metal‐polymer semiconductor interaction, to boost efficient and durable urea synthesis. In situ Raman spectroscopy identified the existence of electron‐deficient Cu sites and was able to withstand electrochemical reduction conditions. Operando synchrotron‐radiation Fourier transform infrared spectroscopy and theoretical calculations disclosed the vital role of electron‐deficient Cu in adsorption and C−N coupling of oxygen‐containing species. The electron‐deficient Cu displayed a high urea yield rate of 255.0 mmol h−1 g−1 at −1.4 V versus the reversible hydrogen electrode and excellent electrochemical durability, superior than that of non‐electron‐deficient counterpart with conductive carbon material as the support. It can be concluded that the regulation of site electronic structure is more important than the optimization of catalyst conductive properties in the C−N coupling reactions. [ABSTRACT FROM AUTHOR]

We texture the Ni electrodes by nanosecond lasers under different conditions and study their electrochemical performance for hydrogen evolution reaction through alkaline water electrolysis. The parameters we vary are the ambient gas (air, N 2 , and Ar) and laser wavelength (1064 or 355 nm), focal length of the f-θ lens (160 and 63 mm), laser power, and beam overlapping. Using a 1 M KOH electrolyte at room temperature we find that the Ni electrode textured by the 355 nm laser in N 2 gas with the f-θ lens of focal length 160 mm shows the best electrochemical performance. The attained overpotential at the current density of −200 mA/cm2 and Tafel slope are 275 mV and 78 mV/dec, respectively. Our results demonstrate that nanosecond laser texturing is a high-speed and cost-effective technique which is industrially suitable to fabricate efficient electrodes for hydrogen evolution reaction. • Nanosecond laser texturing of electrode produces hierarchical micro/nanostructures. • Morphology of the textured surface strongly depends on the texturing parameters. • Choice of laser wavelength and ambient gas is important to achieve high HER. • Too much laser-texturing results in deep microstructures to spoil the HER activity. [ABSTRACT FROM AUTHOR]

Sleep is a prominent physiological state observed across the animal kingdom. Yet, for some animals, our ability to identify sleep can be masked by behaviors otherwise associated with being awake, such as for some sharks that must swim continuously to push oxygenated seawater over their gills to breathe. We know that sleep in buccal pumping sharks with clear rest/activity cycles, such as draughtsboard sharks (Cephaloscyllium isabellum, Bonnaterre, 1788), manifests as a behavioral shutdown, postural relaxation, reduced responsiveness, and a lowered metabolic rate. However, these features of sleep do not lend themselves well to animals that swim nonstop. In addition to video and accelerometry recordings, we tried to explore the electrophysiological correlates of sleep in draughtsboard sharks using electroencephalography (EEG), electromyography, and electrooculography, while monitoring brain temperature. The seven channels of EEG activity had a surprising level of (apparent) instability when animals were swimming, but also when sleeping. The amount of stable EEG signals was too low for replication within‐ and across individuals. Eye movements were not measurable, owing to instability of the reference electrode. Based on an established behavioral characterization of sleep in draughtsboard sharks, we offer the original finding that muscle tone was strongest during active wakefulness, lower in quietly awake sharks, and lowest in sleeping sharks. We also offer several critical suggestions on how to improve techniques for characterizing sleep electrophysiology in future studies on elasmobranchs, particularly for those that swim continuously. Ultimately, these approaches will provide important insights into the evolutionary confluence of behaviors typically associated with wakefulness and sleep. Research Highlights: Some fishes need to swim to breathe, which makes it difficult to identify sleep because the animal is continuously moving. Here, we present relaxed muscle tone as an electrophysiological characteristic of sleep in draughtsboard sharks. [ABSTRACT FROM AUTHOR]

The exponential growth of electrical resistivity tomography (ERT) methods for exploring the subsurface at large depths widened the applicability of the self-potential (SP) method, a passive geoelectrical technique suitable for a variety of purposes like mapping ore bodies or inferring fluid flow in the subsurface. Several new-generation resistivity meters have been designed to continuously log the electric potentials thus allowing for the identification of weak amplitude signals and resulting in deeper inversion models. In such approaches, long SP time-series are collected but are totally ignored as only marginal intervals are retained and analysed in the ERT procedure. The discarded SP records could be valuable although not collected using the traditional methodology, based on a reference electrode. We present an SP forward modelling feasibility study of different array techniques, based on numerical finite-element methods. The SP has been modelled in a variety of electrical settings to assess the imaging potentials of non-conventional (i.e. sparse gradient and full sparse gradient) arrays in comparison to traditional (i.e. fixed-base and the leapfrog) arrays. The analytic signal amplitude (ASA) algorithm was employed to compare numerical modelling results obtained from the different type of arrays, highlighting the great potentials of non-conventional arrays for the recognition of several sources of SP anomalies. The ASA maps, presenting a single peak centred over the targets, can significantly help in identifying the source anomalies for all the analysed array techniques. The cost-effectiveness along with the imaging capability of these non-conventional arrays constitute important benefits that could be exploited resulting in a systematic inclusion of SP analysis when collecting deep ERT data using distributed systems. [ABSTRACT FROM AUTHOR]

The catalytic CO 2 conversion activity of well-defined M-N 3 C 1 sites is evaluated by density functional theory calculations and subsequent experimental tests. [Display omitted] Asymmetric nitrogen/carbon-coordinated single metal sites (M-N x C 4-x) outperform symmetric M-N 4 sites in carbon dioxide (CO 2) electroreduction. However, the challenge of crafting well-defined M-N x C 4-x sites complicates the understanding of their structure-catalytic performance relationship. In this study, we employ metallized N -confused tetraphenylporphyrin (M-NCTPP) to investigate CO 2 conversion on M-N 3 C 1 sites using both density functional theory and experimental methods. The optimal cobalt (Co)-N 3 C 1 site (Co-NCTPP) achieves a current density of 500 mA cm−2 and a carbon monoxide Faraday efficiency exceeding 90 % at −1.25 V vs. the reversible hydrogen electrode, surpassing the performance of Co-N 4 (Co-TPP). This research introduces a novel approach for designing and synthesizing high-activity heteroatom-anchored single metal sites, advancing fundamental understanding in the field. [ABSTRACT FROM AUTHOR]

[Display omitted] Regulating the electron structure and precise loading sites of metal-active sites within the highly conjugated and porous covalent-triazine frameworks (CTFs) is essential to promoting the nitrogen reduction reaction (NRR) performance for electrocatalytic ammonia (NH 3) synthesis under ambient conditions. Herein, experimental method and density functional theory (DFT) calculations were conducted to deeply probe the effect on NRR of the modulation of modulating the electron structure and the loading site of gold nanoparticles (Au NPs) in a two-dimensional (2D) CTF. 2D CTF synthesized using melem and hexaketocyclohexane octahydrate as building blocks (denoted as M−HCO−CTF) served as a robust scaffold for loading Au NPs to form an M−HCO−CTF@AuNP hybrid. DFT results uncovered that well-defined Au sites with tunable local structure were the active site for driving the NRR, which can significantly suppress the conversion of H+ into *H adsorption and enhance the nitrogen (N 2) adsorption/activation. The overlapped Au (3 d) and *N 2 (2 p) orbitals lowered the free energy of the rate-determining step to form *NNH, thereby accelerating the NRR. The M−HCO−CTF@AuNPs electrocatalyst exhibited a large NH 3 yield rate of 66.3 μg h−1 mg−1 cat. and a high Faraday efficiency of 31.4 % at − 0.2 V versus reversible hydrogen electrode in 0.1 M HCl, superior to most reported CTF-based ones. This work can provide deep insights into the modulation of the electron structure of metal atoms within a porous organic framework for artificial NH 3 synthesis through NRR. [ABSTRACT FROM AUTHOR]

Due to fossil fuel depletion and increasing pollution, researchers are now finding ways to develop alternative fuels. Recently, hydrogen became the most focused alternative that can act as a future fuel. Electrochemical water splitting is the cleanest method of producing oxygen and hydrogen from water. Costly noble metal-based materials are used for water splitting and oxygen generation, so there is a strong need to replace platinum with non-precious materials for water splitting. The morphology of the material has a considerable impact on its physical properties and performance. In this research work, we have synthesized flower-shaped nickel cobalt sulfide (NCS-AA) material via a facile hydrothermal method. The material was characterized using SEM and EDS for morphology observation and elemental analysis. The SEM results showed the formation of a flower-type morphology with a diameter of 500 nm to 2 µm and EDS analysis confirmed the presence of Ni, Co, and S. Further, electrochemical analysis was carried out to analyze its performance in oxygen evolution reaction (OER) by performing CV, LSV, and CA analysis techniques. NCS-AA demonstrated good OER activity with an overpotential of ~ 320 mV and a Tafel slope of 115 mV/dec versus a reversible hydrogen electrode for 10 mA/cm2 current density. Further, the stability of NCS-AA materials at 50 mA/cm2 and 200 mA/cm2 was excellent as examined using the chronopotentiometry technique. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction in alkaline water electrolysis is facilitated through the electrodeposition of trimetallic catalyst on nickel foam using the chronoamperometry technique. Specifically, the trimetallic catalyst CoWRu@NF is deposited onto a nickel foam substrate. The catalytic performance of this trimetallic catalytic electrode for the Hydrogen Evolution Reaction (HER) is then assessed in a 1.0 M potassium hydroxide (KOH) solution. This specially designed trimetallic catalytic electrode system efficiently provides the more active sites through the Co component. Subsequently, it facilitates the reduction of protons (H+) to generate hydrogen gas using the Ru component. Tungsten acts as a co‐catalyst in the system for water dissociation promotor by removing hydroxide formed after water dissociation and preventing the deactivation of Ruthenium by certain reaction intermediates. The CoWRu@NF trimetallic catalyst demonstrates excellent activity, showcasing a low overpotential (−8 mV) to achieve a current density of (−10 mA/cm2. Additionally, it exhibits low Tafel slope values (101.2 mV dec−1), credited to the presence of cobalt and tungsten alongside Ruthenium in the catalytic system. This configuration is specifically designed to enhance the kinetics of the hydrogen‐evolving reaction. [ABSTRACT FROM AUTHOR]

The engineering of the spin state and axial coordination of the metal center of single‐atom catalyst (SAC) represents an effective strategy for regulating the catalytic activity, selectivity, and stability toward electrocatalytic reduction of CO2 (ECO2R). However, rational design and deliberate fabrication of SACs with axial coordination of specified atoms remain challenging. Herein, Ni single atoms with axial coordination of phosphorus (NiP−N4−C) and four planar nitrogen atoms are fabricated, which induces reorientation of the 3d orbitals of the Ni atom and shift of the spin state from low (S = 0) to high (S = 2). The enhanced d−p orbital coupling between the Ni and the adsorbents enhances CO2 activation and reduces energy barrier for formation of *COOH, a key intermediate in the ECO2R to produce CO, enabling the high activity and near unity selectivity of CO in ECO2R in a broad potential range of 600 mV (−0.4–−1.0 V vs reversible hydrogen electrode vs RHE), achieving a turnover frequency of 37.2 s−1 at −1.0 V versus RHE. As a bifunctional cathode electrocatalyst, NiP−N4−C demonstrates a peak power density of 18.5 mW cm−2 and maintains cycling durability over 70 h in rechargeable Zn−CO2 batteries. [ABSTRACT FROM AUTHOR]

Electrochemical nitrate reduction reaction (NO3RR) offers a route to balanced nitrogen cycle and sustainable ammonia production. However, unsatisfied performance in neutral media arising from competitive hydrogen evolution reaction and inefficient hydrogenation impede the further applications of NO3RR. Herein, the rational design of RuNi alloy nanostructures is reported. Benefited from the synergism effect between Ru and Ni, Ru20Ni80 alloy exhibits a high NH3 Faradaic efficiency of 98.02% at −0.35 V (vs reversible hydrogen electrode (RHE)) and a large NH3 yield rate of 27.88 mg mgcat−1 h−1 at −0.65 V (vs RHE). Importantly, the atomic scale cooperation between Ru and Ni active sites endows RuNi alloy a close‐to‐unity NH3 selectivity via HNO* pathway. Theoretical calculations have revealed that the interactions between Ru and Ni optimize the electronic structures of Ru20Ni80 alloy, where Ru sites with enhanced electroactivity improve the generation of active hydrogens and more electron‐rich Ni sites facilitate the reduction of nitrate. Accordingly, the adsorption strengths of key intermediates become stronger and the energy barriers of NO3RR are reduced to guarantee efficient NO3RR. Furthermore, a flow‐type reactor coupled with coprecipitation is established to achieve continuous NH3 generation and recovery as struvite. [ABSTRACT FROM AUTHOR]

A gas-penetrable electrode (GPE) composed of a Bi nanosheet array-wrapped Cu hollow fiber (Bi NSAs@Cu HF) is rationally designed and utilized for efficient electrocoupling of CO2 and N2 to produce urea with a yield of 79 μg h−1 cm−2, a faradaic efficiency (FEurea) of 6.8%, and excellent cycling stability at −0.2 V vs. reversible hydrogen electrode (RHE). [ABSTRACT FROM AUTHOR]

While developing battery cells, the achievement of fast-charging capability is heavily dependent on avoiding metallic plating on the anode surface (i.e., lithium plating in lithium-ion cells). However, this objective hinges on the effectiveness of plating detection. Currently, measurement techniques are either inadequate in providing spatial, temporal, or causal information, incur high costs when employing, e.g., neutron imaging, or are lengthy due to destructive post-mortem examinations that additionally lack operando data. In this work, we demonstrate an ultrasound imaging method for operando visualization of the interior of a multi-layer pouch battery cell. Here we show that this method can non-invasively visualize the formation and stripping of lithium plating during cycling. Extensive reference electrode studies and ex-situ analysis verify the effectiveness of our method for plating detection. Ultimately, this work enables researchers and industry to significantly accelerate the development of new cell technologies and their optimized utilization. The authors have demonstrated a method for real-time imaging of the interior of a battery using ultrasound imaging. This approach reveals effects that hinder fast charging, enabling researchers to develop new batteries and optimize their utilization. [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]

Electrochemical reduction reaction of CO2 (eCO2RR) to produce valuable chemicals offers an attractive strategy to solve energy and environmental problems simultaneously. We have mapped out entire reaction pathways of eCO2RR to CO on Cu(100), including all intermediates and transition states using first‐principles simulations. To accurately account for the solvent effect, the reaction was investigated with and without explicit water molecules, highlighting the limitations of the often (mis)used vacuum reaction pathway simplification. The results show that the reduction reaction was initiated under neutral pH conditions at an applied potential of −0.11 V (RHE, reversible hydrogen electrode) and all elementary reactions were thermodynamically favorable, while an applied potential of −1.24 V is required to ensure that all reactions exhibit spontaneous behavior. Detailed analysis revealed that solvation significantly influences the stability of the adsorbates and intermediates. Its inclusion notably alters the calculated reaction kinetics and energetic parameters by lowering the barrier energies and Gibbs free energies of all reactions. CO production proceeded mainly via the COOH* pathway (CO2 →trans‐COOH*→cis‐COOH*→CO*+OH*→CO*→CO). The use of water as a more sustainable and cost‐effective solvent is compared to other options such as organic solvents, ionic liquids and mixed solvent systems, which are less sustainable and more expensive. [ABSTRACT FROM AUTHOR]

The design of high-efficiency and cost-effective electrocatalysts for water splitting has recently received much attention. Herein, a self-supported Fe-doped NiMo/NiCo bifunctional electrocatalyst was synthesized using hydrothermal method on nickel foam (NF) to enhance both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). SEM observations revealed NiCo microspheres arranged in a flower-like structure, with Fe-doped NiMo rods decorating the surface. This electrocatalyst demonstrated impressive HER performance, requiring a low overpotential of 63 mV, versus reversible hydrogen electrode (RHE), at a cathodic current density of −10 mA/cm2, and a small charge transfer resistance (R ct) of 2.43 Ω at −200 mV (RHE). For OER, the synthesized electrocatalyst revealed excellent activity, with a low overpotential of 151 mV (RHE) to afford an anodic current density of 10 mA/cm2 and a small R ct of 0.43 Ω at 300 mV (RHE). Meanwhile, the Fe-doped NiMo/NiCo@NF electrocatalyst in a two-electrode configuration needed only a cell voltage of 1.53 V to deliver a current density of 10 mA/cm2. Overall, this work disclosed that the combination of NiCo and NiMoFe results in the synthesis of a heterogeneous electrocatalyst that offers high efficiency for water splitting and maintains good stability over 10 h. [Display omitted] • A hierarchical Fe-doped NiMo/NiCo@NF electrocatalyst, was synthesized by the hydrothermal method. • Large specific surface area, abundant active sites, and synergistic effects between constituents enhanced both HER and OER activity. • This electrocatalyst displayed appropriate structural and performance stability for10 h. [ABSTRACT FROM AUTHOR]

The consumption of the Pt electrocatalyst, which occurs when aqueous solution with neutral pH is electrolyzed with a Pt electrode to produce hydrogen or oxygen, was measured from the change in resonance frequency using the QCM method. First, it was found that the Pt consumption from the electrode during water electrolysis while applying a steady positive potential was very small, but it was almost proportional to the time the current was applied. Second, when electrolysis was performed by polarity reversal electrolysis of the anode and cathode periodically during electrolysis, the amount of Pt consumed increased in proportion to the number of polarity reversal was exchanged. The Pt consumption obtained by the QCM method was in close agreement with the value obtained by EDX method, proving the validity of the measurement method. The QCM measurement method was also proven to be a reliable method of measurement. • Constant-current water electrolysis, Pt anode consumed slightly with time. • Polarity reversals water electrolysis, Pt consumed increases with number of times. • Chloride ion concentration affects Pt electrode consumption in a nonlinear manner. [ABSTRACT FROM AUTHOR]

Tuning the electronic structure of catalysts is an efficient approach to optimize the catalytic performance of CO2 electroreduction. Herein, we constructed an efficient catalyst consisting of amorphous InOX with a cotton‐like structure spreading over N doped carbon (N−C) substrate to extend the catalysts‐substrate interfaces for enhancing electron‐transfer effect. The amorphous InOX growing on N−C substrate (InOX/N−C) exhibited an improved current density of −34.4 mA cm−2. Notably, a faradaic efficiency for formate (HCOO−) over the amorphous InOX/N−C reached 79.6 % at −1.0 V versus reversible hydrogen electrode, 1.8 times as high as that (44.2 %) over the amorphous InOX growing on carbon black substrate. Mechanistic studies revealed that the introduction of N−C as substrates accelerated charge‐transfer process on the catalytic surface of InOX/N−C. Density functional theory calculations further revealed that the interactions between N−C substrate and InOX not only facilitated the potential‐determining *HCOO protonation, but also inhibited hydrogen evolution, thus improving the catalytic performance for the production of HCOO−. [ABSTRACT FROM AUTHOR]

Developing sustainable energy solutions is critical for addressing the dual challenges of energy demand and environmental impact. In this study, a zinc‐nitrate (Zn−NO3−) battery system was designed for the simultaneous production of ammonia (NH3) via the electrocatalytic NO3− reduction reaction (NO3RR) and electricity generation. Continuous wave CO2 laser irradiation yielded precisely controlled CoFe2O4@nitrogen‐doped carbon (CoFe2O4@NC) hollow nanocubes from CoFe Prussian blue analogs (CoFe‐PBA) as the integral electrocatalyst for NO3RR in 1.0 M KOH, achieving a remarkable NH4+ production rate of 10.9 mg h−1 cm−2 at −0.47 V versus Reversible Hydrogen Electrode with exceptional stability. In situ and ex situ methods revealed that the CoFe2O4@NC surface transformed into high‐valent Fe/CoOOH active species, optimizing the adsorption energy of NO3RR (*NO2 and *NO species) intermediates. Furthermore, density functional theory calculations validated the possible NO3RR pathway on CoFe2O4@NC starting with NO3− conversion to *NO2 intermediates, followed by reduction to *NO. Subsequent protonation forms the *NH and *NH2 species, leading to NH3 formation via final protonation. The Zn−NO3− battery utilizing the CoFe2O4@NC cathode exhibits dual functionality by generating electricity with a stable open‐circuit voltage of 1.38 V versus Zn/Zn2+ and producing NH3. This study highlights the innovative use of CO2 laser irradiation to transform Prussian blue analogs into cost‐effective catalysts with hierarchical structures for NO3RR‐to‐NH3 conversion, positioning the Zn−NO3− battery as a promising technology for industrial applications. [ABSTRACT FROM AUTHOR]

The acidic electrocatalytic conversion of CO2 to multi‐carbon (C2+) oxygenates is of great importance in view of enhancing carbon utilization efficiency and generating products with high energy densities, but suffering from low selectivity and activity. Herein, we synthesized Ag−Cu alloy catalyst with highly rough surface, by which the selectivity to C2+ oxygenates can be greatly improved. In a strongly acidic condition (pH=0.75), the maximum C2+ products Faradaic efficiency (FE) and C2+ oxygenates FE reach 80.4 % and 56.5 % at −1.9 V versus reversible hydrogen electrode, respectively, with a ratio of FEC2+ oxygenates to FEethylene up to 2.36. At this condition, the C2+ oxygenates partial current density is as high as 480 mA cm−2. The in situ spectra, control experiments and theoretical calculations indicate that the high generation of C2+ oxygenates over the catalyst originates from its large surface roughness and Ag alloying. [ABSTRACT FROM AUTHOR]

Modifying catalyst surface with small molecular‐additives presents a promising avenue for enhancing electrocatalytic performance. However, challenges arise in preserving the molecular‐additives and maximizing their tuning effect, particularly at high current densities. Herein, we develop an effective strategy to preserve the molecular‐additives on electrode surface by applying a thin protective layer. Taking 4‐dimethylaminopyridine (DMAP) as an example of a molecular‐additive, the hydrophobic protection layer on top of the DMAP‐functionalized Cu‐catalyst effectively prevents its leaching during CO2 electroreduction (CO2R). Consequently, the confined DMAP molecules substantially promote the CO2‐to‐multicarbon conversion at low overpotentials. For instance, at a potential as low as −0.47 V vs. reversible hydrogen electrode, the DMAP‐functionalized Cu exhibits over 80 % selectivity towards multi‐carbon products, while the pristine Cu shows only ~35 % selectivity for multi‐carbon products. Notably, ethanol appears as the primary product on DMAP‐functionalized Cu, with selectivity approaching 50 % at a high current density of 400 mA cm−2. Detailed kinetic analysis, in situ spectroscopies, and theoretical calculations indicate that DMAP‐induced electron accumulations on surface Cu‐sites decrease the reaction energy for C−C coupling. Additionally, the interactions between DMAP and oxygenated intermediates facilitate the ethanol formation pathway in CO2R. Overall, this study showcases an effective strategy to guide future endeavors involving molecular tuning effects. [ABSTRACT FROM AUTHOR]

Partial electro‐oxidation using renewable electricity offers a sustainable route for valorizing glycerol, a major by‐product of biofuel production. This study introduces a bimetallic electrode with nanostructured platinum dendrites on nickel foam (Pt/NiF), achieving a peak geometric current density of 235 mA cm−2 and a Pt‐mass normalized current density of 3.71 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$ for glycerol electro‐oxidation at 0.92 V versus a reversible hydrogen electrode (RHE) in 3 m KOH electrolyte containing 1 m glycerol, outperforming most previously reported Pt‐containing catalysts. The Pt/NiF electrode demonstrates over 92% cumulative selectivity toward C3 products, with 64% selectivity for lactic acid at 0.65 V versus RHE over 5 h of testing. This research also highlights the role of chemical oxidation pathways (isomerization and rearrangements) in converting glycerol to lactic acid. After 5 h at 0.65 V versus RHE, the Pt/NiF electrode maintains 35% of its initial current density, plateauing at 12.2 mA cm−2 (0.15 AmgPt−1${\mathrm{A\ mg}}_{{\mathrm{Pt}}}^{ - {\mathrm{1}}}$), with performance loss likely due to surface poisoning by carbon‐based reaction intermediates/byproducts or passivating platinum (hydr)oxide species. These findings pave the way for developing low‐platinum group metal catalysts with high glycerol oxidation affinity and highlight the importance of considering chemical transformations during catalyst evaluation and reactor design. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atomically dispersed catalyst with single Cu atom and atomic Ni clusters was prepared. • Cu SA Ni AC /NMHCS achieves a high FE CO of over 90% across a wide potential range. • Cu SA Ni AC /NMHCS shows the highest FE CO of 98 % at − 0.9 V vs. RHE. • Cu SA Ni AC /NMHCS exhibits excellent long-term stability for CO 2 RR to produce CO. • Positively shifted ε d of Ni 3 d orbital contributes to the enhanced CO 2 RR performance. The rational design of catalysts with atomic dispersion and a deep understanding of the catalytic mechanism is crucial for achieving high performance in CO 2 reduction reaction (CO 2 RR). Herein, we present an atomically dispersed electrocatalyst with single Cu atom and atomic Ni clusters supported on N-doped mesoporous hollow carbon sphere (Cu SA Ni AC /NMHCS) for highly efficient CO 2 RR. Cu SA Ni AC /NMHCS demonstrates a remarkable CO Faradaic efficiency (FE CO) exceeding 90% across a potential range of −0.6 to −1.2 V vs. reversible hydrogen electrode (RHE) and achieves its peak FE CO of 98% at −0.9 V vs. RHE. Theoretical studies reveal that the electron redistribution and modulated electronic structure—notably the positive shift in d-band center of Ni 3 d orbital—resulting from the combination of single Cu atom and atomic Ni clusters markedly enhance the CO 2 adsorption, facilitate the formation of *COOH intermediate, and thus promote the CO production activity. This study offers fresh perspectives on fabricating atomically dispersed catalysts with superior CO 2 RR performance. [ABSTRACT FROM AUTHOR]

α‐Mn[N(CN)2]2 (Pnnm) with divalent Mn2+ being octahedrally coordinated by six [N(CN)2]− dicyanamide (dca‒) complex anions is known since 1999. A novel β polymorph is now prepared and its structure characterized via powder X‐ray diffraction. β‐Mn[N(CN)2]2 also crystallizes orthorhombically (Cmcm) but with Mn2+ tetrahedrally coordinated to four [N(CN)2]− anions. Property‐wise, α‐Mn[N(CN)2]2 can be efficiently used as a negative electrode material for lithium‐ion batteries, maintaining a large reversible capacity of more than 600 mAh g−1 for 250 cycles tested at 0.5 C, comparing favorably to well‐established negative electrode references such as graphite (≈372 mAh g−1). The electrochemical lithiation/delithiation mechanism of α‐Mn[N(CN)2]2 is investigated using advanced characterization techniques and theoretical calculations. Upon lithiation, α‐Mn[N(CN)2]2 undergoes a reversible conversion reaction, forming LiN(CN)2 and metallic manganese, which are transformed back into α‐Mn[N(CN)2]2 upon delithiation. Further, there is evidence for reversible and additional charge/discharge processes on the dca‒ anion throughout the entire discharge/charge process in α‐Mn[N(CN)2]2, reflecting an anionic charge compensation. Moreover, density‐functional (DFT) and chemical‐bonding theory are employed to investigate the detailed anodic behavior of α‐Mn[N(CN)2]2 via conversion reaction during (de‐)lithiation processes. This mechanism, evidenced for the first time in transition metal dicyanamides, is likely behind its outstanding electrochemical properties. [ABSTRACT FROM AUTHOR]

Ozonation water treatment technology has attracted increasing attention due to its environmental benign and high efficiency. Rutile PbO2 is a promising anode material for electrochemical ozone production (EOP). However, the reaction mechanism underlying ozone production catalyzed by PbO2 was rarely studied and not well‐understood, which was in part due to the overlook of the electrochemistry‐driven formation of oxygen vacancy (OV) of PbO2. Herein, we unrevealed the origin of the EOP activity of PbO2 starting from the electrochemical surface state analysis using density functional theory (DFT) calculations, activity analysis, and catalytic volcano modeling. Interestingly, we found that under experimental EOP potential (i. e., a potential around 2.2 V vs. reversible hydrogen electrode), OV can still be generated easily on PbO2 surfaces. Our subsequent kinetic and thermodynamic analyses show that these OV sites on PbO2 surfaces are highly active for the EOP reaction through an interesting atomic oxygen (O*)‐O2 coupled mechanism. In particular, rutile PbO2(101) with the "in‐situ" generated OV exhibited superior EOP activities, outperforming the (111) and (110) surfaces. Finally, by catalytic volcano modeling, we found that PbO2 is close to the theoretical optimum of the reaction, suggesting a superior EOP performance of rutile PbO2. All these analyses are in good agreement with previous experimental observations in terms of EOP overpotentials. This study provides the first volcano model to explain why rutile PbO2 is among the best metal oxide materials for EOP and provides new design guidelines for this rarely studied but industrially promising reaction. [ABSTRACT FROM AUTHOR]

With the continuous pursuing on the improvement of catalytic activity, a catalyst performed exceeding catalytic volcano plots is desired, while it is impeded by the adsorption‐energy scaling relations of reaction intermediates. Numerous efforts have been focused on optimizing the initial and final intermediates to circumvent the scaling relations for an improved performance. For a step forward, simultaneously optimizing all intermediates is essential to explore the theoretical maximum of catalytic activity. Herein, we proposed a dynamic adsorption mechanism (DAM) to independently regulate the adsorption configurations of all intermediates of electrochemical nitrogen reduction reaction (NRR). To demonstrate the DAM, a multi‐site NbNi3 intermetallic is developed, which enables suitable adsorption energies of different intermediates via modulating orbital coupling mechanisms. As a result, NbNi3 achieves an ultra‐low limiting potential of NRR of −0.11 V vs. reversible hydrogen electrode (RHE). Strikingly, the theoretical result is confirmed by a proof‐of‐concept experiment, wherein the nanoporous NbNi3 electrode exhibits a remarkable NH3 yield rate of 25.89 μg h−1 cm−2 with the Faradaic efficiency of 33.15 % at −0.25 V vs. RHE. Overall, this work brings out a new strategy to avoid the scaling relations, and opens up a promising avenue toward high‐efficiency NRR catalysts. [ABSTRACT FROM AUTHOR]

Metal‐coordinated N‐doped carbon (M‐N‐C) materials with highly curved structures have become a promising class of electrocatalysts for the oxygen reduction reaction (ORR). However, the stability of these electrocatalysts remains a problem due to the traditional post‐metal loading strategy. Herein, single‐atomic Co‐N‐C active sites anchored on helical carbonaceous nanotubes (HCNTs) are prepared (Co‐N‐C@HCNT) by pyrolyzing Co porphyrins and helical polypyrroles (PPys) mixtures at high‐temperature by one‐step method. Aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and X‐ray absorption fine structure (XAFS) measurements confirm single‐atomic active sites and Co‐N4 coordination structures of Co‐N‐C@HCNT. The optimized Co‐N‐C@HCNT exhibits excellent catalytic ORR activity with a half‐wave potential (E1/2) of 0.86 V versus reversible hydrogen electrode (vs RHE) compared to Co‐N‐C@CNT without helical structures (E1/2 = 0.81 V vs RHE) measured in 0.1 m KOH. Co‐N‐C@HCNT also displays excellent stability with a slight current decrease (4%) after running for 10 h featuring Co‐N4 active sites tightly anchored on HCNTs due to electrostatic interactions between metal porphyrins and PPys. Theoretical calculations indicate that the curved structure can increase the charge and decrease d‐band center at Co active site, which enhances electrocatalytic activity. This work provides a simple but effective strategy to construct helical M‐N‐C materials. [ABSTRACT FROM AUTHOR]

Reference electrodes which demonstrate long-term potential stability are essential for many continuous monitoring applications and are commonly based on Ag‖AgCl electrodes; however, these electrodes are susceptible to poisoning from aqueous sulphide species which are commonly present in wastewater and natural groundwater. This work presents a sulphide resistant solid-state reference electrode (SSRE) based on a composite material using suspended KCl electrolyte and sacrificial AgCl in a cross-linked polyvinyl acetate polymer matrix. Sulphidation of the sacrificial AgCl produces a stable Ag2S precipitate and prevents further ingress of the poisoning sulphide species through the composite material. A novel SSRE using this material is compared to a control SSRE without suspended AgCl and a typical liquid filled reference electrode. These three reference electrodes are studied using electrochemical impedance spectroscopy (EIS), and their application is also studied in potentiometric pH sensing and cyclic voltammetry (CV). The long-term sulphide resistance of the two SSREs is also studied with potentiometry, and cross-sections of these electrodes were examined using micro X-ray fluorescence (μXRF). Both SSREs demonstrated higher impedance than the liquid reference electrode but were similar to other SSREs reported in the literature. This impedance did not result a meaningful difference in potentiometric pH sensing or CV experiments done using typical scan rates. The KCl/AgCl SSRE exhibited remarkable sulphide resistance, with all samples demonstrating a stable potential without maintenance after ca. 120 days of continuous immersion in 1 g L−1 Na2S solution, whereas KCl SSRE samples all demonstrated significant drift before this time. μXRF sulphur maps revealed that suspended AgCl prevented sulphide ingress, thus protecting the embedded Ag‖AgCl electrode. This work presents a reference electrode that could enable long-term monitoring in challenging sulphide solutions, and also highlights a novel approach for preventing reference electrode poisoning which could be more widely explored. [ABSTRACT FROM AUTHOR]

Constructing an internal electric field (IEF) within the hematite (Fe2O3) photoanode for highly efficient water oxidation performance with facilitated charge transfer and separation remains still a significant challenge. Unlike the conventional approach of creating interfacial electric fields through heterojunction design by introducing another semiconductor, a novel strategy is proposed for engineering localized n‐p homojunctions on the surface of Fe2O3 photoanode using gradient Zn2+ doping strategy. By implementing this approach, the inherent n‐type characteristics of Fe2O3 can be transformed into p‐type, thereby facilitating the formation of an n‐p junction with robust IEF, which enables more efficient charge separation and transfer. Additionally, the gradient Zn2+ doping is accompanied by the generation of oxygen vacancies, which further improves the charge transfer efficiency and accelerates water oxidation kinetics. As expected, the photocurrent density of optimized Fe2O3 photoanode at 1.23 V versus reversible hydrogen electrode is ≈2.6‐fold that of Fe2O3. This work provides a novel perspective on the design of localized n‐p homojunction within photoanodes for achieving high solar energy conversion efficiency. [ABSTRACT FROM AUTHOR]

It is still a great challenge to achieve high selectivity of ethanol in CO2 electroreduction reactions (CO2RR) because of the similar reduction potentials and lower energy barrier of possible other C2+ products. Here, we report a MOF‐based supported low‐nuclearity cluster catalysts (LNCCs), synthesized by electrochemical reduction of three‐dimensional (3D) microporous Cu‐based MOF, that achieves a single‐product Faradaic efficiency (FE) of 82.5 % at −1.0 V (versus the reversible hydrogen electrode) corresponding to the effective current density is 8.66 mA cm−2. By investigating the relationship between the species of reduction products and the types of catalytic sites, it is confirmed that the multi‐site synergism of Cu LNCCs can increase the C−C coupling effect, and thus achieve high FE of CO2–to–ethanol. In addition, density functional theory (DFT) calculation and operando attenuated total reflectance surface‐enhanced infrared absorption spectroscopy further confirmed the reaction path and mechanism of CO2–to–EtOH. [ABSTRACT FROM AUTHOR]

Hydrogen is a renewable and environmentally friendly energy carrier and is considered a viable alternative to fossil fuels. Consequently, developing electrodes with excellent hydrogen evolution electrocatalysis is a top priority in research. However, the use of flat electrodes as cathode substrates by most researchers limits the electrocatalytic active area of the prepared electrode. To address this issue, it is essential to prepare a micro-nano structure on a cathode substrate before electrodeposition. This study introduced a novel Ni nanocone/Grid electrode, obtained through a combined laser-electrodeposition process to investigate its electrocatalytic activity and stability for the hydrogen evolution reaction (HER). Various techniques, including linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), cyclic voltammetry (CV), and chronopotentiometry (CP) in 1 M KOH solution, were employed to assess the HER electrocatalytic performance of the Ni nanocone/Grid electrodes. The experimental results demonstrated that the electrodes could achieve current densities of -10, -20, and -100 mA/cm2 with corresponding overpotentials of -281, -308, and -390 mV, respectively. Additionally, the Tafel slope of these electrodes was found to be only -82.05 mV/dec. The enhanced catalytic performance of the electrode was attributed to the synergistic effect of the grid-like and nanocone structures, which significantly increased the electrocatalytically active area and improved surface hydrophilicity, thereby boosting electrocatalytic performance. The simplicity of the preparation method and the exceptional performance of the electrode provide a promising new avenue for future research on HER electrocatalysts. • A new laser-electrodeposition combined process was proposed to prepare the catalytic electrode for hydrogen evolution. • Ni nanocone/Grid showed low overpotential and Tafel slope for hydrogen evolution. • The combination of grid structure and nanocone can significantly increase the ECSA of the electrode. • The electrode shows excellent hydrophilicity and extraordinary durability. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BVO) with a small band gap and suitable band edges is regarded as one of the promising photocatalysts for water oxidation. However, the short charge-transfer path limits its photocatalytic performance. Establishing a heterojunction and incorporating a co-catalyst are feasible methods to improve the photocatalytic ability of BVO by enhancing carrier transfer rates and reducing in-electrode resistances. In this study, nickel tellurium oxide (NTO) and cobalt iron Prussian blue analogues (CoFePBA) are incorporated into the BVO electrode to respectively develop a heterojunction and decorate co-catalyst for efficiently catalyzing the water oxidation reaction for the first time. Different amounts of CoFePBA are deposited on the NTO/BVO electrode by varying the electrodeposition durations to enhance exited charge generations and maintain high absorbance of incident light. The largest photocurrent density of 6.55 mA/cm2 at 1.23 V versus reversible hydrogen electrode is attained for the optimal CoFePBA/NTO/BVO electrode prepared using an electrodeposition duration of 2 min. Excellent catalytic stability is also achieved, with the photocurrent retention of 91.9% after illuminating the electrode for 5000 s. This study provides blueprints for incorporating novel electrochemically active materials in the BVO system to realize heterojunction and co-catalyst strategies, thereby attaining excellent photocatalytic ability toward water oxidation. [Display omitted] • Ni–Te oxide (NTO) and Co–Fe Prussian blue analogue (CoFePBA) combined in BiVO 4 (BVO). • Heterojunction and co-catalyst are made for catalyzing water oxidation efficiently. • Different CoFePBA amount is deposited on NTO/BVO by varying electrodeposition times. • A photocurrent density of 6.55 mA/cm2 at 1.23 V RHE is obtained for CoFePBA/NTO/BVO. • Excellent stability is achieved with a photocurrent retention of 91.9% after 5000 s. [ABSTRACT FROM AUTHOR]

Creating innovative catalysts utilizing nonprecious metals for the electrocatalytic hydrogen evolution reaction (HER) poses a significant difficulty. We present a cobaloxime (Cox) complex having pyridine (2-Cox) and tetrafluorophenyl-thio-pyridine (4-Cox) functional groups, which contains a 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) moiety. This combination serves as a catalyst for proton reduction and is immobilized onto reduced graphene oxide (rGO) by π–π stacking between the cobaloxime complex and rGO. Moreover, the unique complex's structures were determined through the application of ultraviolet–visible spectroscopy (UV–Vis), Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM). The electrocatalytic activity of the two rGO/2-Cox and rGO/4-Cox electrodes towards hydrogen (H 2) were examined under both alkaline and acidic conditions. The cobaloxime-modified rGO electrodes demonstrate superior electrocatalytic performance for the HER under acidic conditions compared to alkaline conditions. The overpotential at a current density of 10 mA cm−2 for rGO/2-Cox in 0.5 M H 2 SO 4 is −0.342 V, which is notably lower than the overpotential of rGO/4-Cox (−0.496 V). The Tafel slope for the rGO/2-Cox electrode in a 0.5 M H 2 SO 4 solution is 111 mV.dec−1, but for the rGO/4-Cox electrode it is 156 mVdec−1. This discrepancy suggests that the rGO/2-Cox electrode demonstrates better performance in the HER compared to the rGO/4-Cox electrode. • Two different BODIPY-cobaloxime complexes were synthesized. • These combinations are immobilized on reduced graphene oxide by π-π stacking. • The electrocatalytic activity of these structures towards hydrogen was studied. • 2-Cox structure exhibited superior electrocatalytic performance for HER. • These catalysts have the potential to be used in various energy applications. [ABSTRACT FROM AUTHOR]

A convenient, non-toxic, and low-cost tin dioxide (SnO2)/nickel oxide (NiO)/reduced graphene oxide (rGO) nanocatalytic electrode was investigated, which can effectively promote the hydrogen evolution reaction and can also be used to construct a sensitive winter wheat cold-tolerant RNA sensor. Due to the good synergy and photocurrent generation between SnO2 and NiO, which accelerates the electron transfer and catalyzes the hydrolysis reaction, the resultant data for the hydrogen evolution reaction in alkaline environment of this material are very impressive, with cathodic current densities of up to 10 mA cm−2. The marvelous heterostructures and photovoltaic properties form a signal amplification system, which enables the nanocomposites to have an excellent linear sensitivity in low-concentration RNA solutions. The single-stranded complementary RNA of the target RNA was immobilized on the surface of the nanocomposites, which enabled the materials to recognize the target RNA under enzyme-free conditions. The test results showed that the modified electrode materials had good single detection performance in a wide linear range from 0.1 nM to 2 mM, with the limit of detection (LOD) of 0.078 nM. The developed nanocomposite electrode has good performance in hydrogen evolution and winter wheat cold-resistant RNA detection, and is a bifunctional device with superior performance. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

Summary: This paper presents an ultrahigh input impedance, low noise, and wide bandwidth four‐channels analog front‐end (AFE) for low‐power neural recording systems. To achieve high input impedance, the buffer channels are placed between the electrodes and the main amplifier stage of the AFE. The buffer is designed with low noise and low power consumption to obtain high input impedance of overall AFE while maintaining low input‐referred noise and low power consumption. A chopper capacitively coupled chopper instrumentation amplifier (CCIA) is placed after the buffer as the main amplifier stage of the AFE to improve the common mode rejection ratio (CMRR) and the input‐referred noise of the overall AFE design. A new chopper stabilization control technique is proposed and used in the CCIA stage to reduce the charge injection and clock feedthrough and consequently the high‐frequency ripple of the AFE output signal. A programmable gain amplifier (PGA) is designed as the third stage to adjust the overall gain of the AFE. Benefiting from PGA, the AFE can adapt its gain with both action potential and local field potential signals. To reduce the number of the electrode to be implanted and reduce the impedance mismatch that causes the degradation on overall CMRR performance, two AFE channels shared a reference electrode followed by a reference buffer. The proposed AFE is designed and simulated using a standard 180 nm CMOS process and operates in a wide frequency band of 2.1 to 2500 Hz with low input‐referred noise of 1.6 μVrms and a CMRR over 80 dB at 2.1 Hz. The total power consumption is lower than 4.3 μW per channel. With the proposed structure of AFE, the input impedance is 35 GΩ @ 21 Hz and the minimum impedance over operational bandwidth is 75 MΩ @ 2.5 kHz. [ABSTRACT FROM AUTHOR]

Monomers: gentian violet (GV), brilliant green (BG), aniline, and methyl violet (MV), as well as their copolymers, were electropolymerized and used to modify glassy carbon electrode (GCE) by enhancing the sensitivity of the electrode. This is due to their special characteristics of sensing ability of the electropolymerized polymers. The electropolymerization and characterization of these monomers and their copolymers were done using cyclic voltammetry (CV) on GCE as a working electrode against Ag/AgCl reference electrode and platinum wire as the counter electrode. The copolymers showed higher current peaks than their corresponding homopolymers. The electrochemical characterization of these polymers and copolymers was studied by scan rate effect each between 10 and 300 mV/s and pH effect between 1.56 and 5.30. After being modified by the copolymers: poly(BG-GV) and poly(BG-MV), the modified GCE showed good results in resolving the peaks of ascorbic acid and uric acid which otherwise showed an overlapped broad peak on bare GCE. The CV in bare GCE was scanned at different scan rates of 4 mM K3[Fe(CN)6] in 1 M KNO3 solution. The square root of scan rate dependence of peak current was plotted and the Randles–Sevcik equation was applied to determine the diffusion coefficient of Fe(CN)63− ion and which was 1.13 × 10–14 cm2/s. This was used to determine the area of the modified electrode after running the CV of 4 mM K3[Fe(CN)6] in 1 M KNO3 at different scan rates. Therefore, the electrochemical polymerization of organic dye polymers was able to increase the sensitivity of the electrode by increasing its area. [ABSTRACT FROM AUTHOR]

This study investigates the impact of the uranium electrodeposition process on a boron-doped diamond electrode (BDD) surface at varying potentials as a means of environmental uranium remediation. The chronoamperometry technique was employed for the electrodeposition process, applying potentials ranging from − 0.60 to − 2.00 V vs. the reversible hydrogen electrode (RHE). A 2-mM uranyl acetate dihydrate (UO2(C2H3O2)2·2H2O) solution in 0.1-M KClO4 served as a model uranyl ion (UO22+) source. Analysis using scanning electron microscopy, energy-dispersive X-ray fluorescence spectroscopy, and atomic force microscopy (AFM) confirmed the presence of uranium and the formation of a thin layer on the electrode surface. Roughness measurements obtained through AFM analysis at different applied potentials vs. RHE were compared before and after uranium electrodeposition at BDD electrodes. Additionally, the identification of various uranium oxides resulting from the electrodeposition procedures was conducted using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. These analyses revealed the presence of UO2, UO3, and U3O8 on the BDD electrode surface due to the electrochemical deposition process, with a notable proportion of U3O8 observed. Ultimately, the optimal potential for efficient U6+ remediation from aqueous media and the formation of a homogenous thin layer conducive to nuclear technology development was determined to be − 1.75 V vs. RHE. [ABSTRACT FROM AUTHOR]

We propose an in situ gas etching-thermal assembly strategy to simultaneously create mesopore-dominated carbon cores with ultrathin carbon-layer shells fully decorated with highly dispersed Mn-N 4 single-atom sites, which was used as a highly active and stable ORR catalyst in zinc-air batteries. [Display omitted] Applications of zinc-air batteries are partially limited by the slow kinetics of oxygen reduction reaction (ORR); Thus, developing effective strategies to address the compatibility issue between performance and stability is crucial, yet it remains a significant challenge. Here, we propose an in situ gas etching-thermal assembly strategy with an in situ -grown graphene-like shell that will favor Mn anchoring. Gas etching allows for the simultaneous creation of mesopore-dominated carbon cores and ultrathin carbon layer shells adorned entirely with highly dispersed Mn-N 4 single-atom sites. This approach effectively resolves the compatibility issue between activity and stability in a single step. The unique core–shell structure allows for the full exposure of active sites and effectively prevents the agglomerations and dissolution of Mn-N 4 sites in cores. The corresponding half-wave potential for ORR is up to 0.875 V (vs. reversible hydrogen electrode (RHE)) in 0.1 M KOH. The gained catalyst (Mn-N@Gra-L)-assembled zinc-air battery has a high peak power density (242 mW cm−2) and a durability of ∼ 115 h. Furthermore, replacing the zinc anode achieved a stable cyclic discharge platform of ∼ 20 h at varying current densities. Forming more fully exposed and stable existing Mn-N 4 sites is a governing factor for improving the electrocatalytic ORR activity, significantly cycling durability, and reversibility of zinc-air batteries. [ABSTRACT FROM AUTHOR]

The self-doping of oxygen vacancy and Ti3+ by electrochemical reduction (ER) method has been proved to be an effective means to improve the PEC performance of TiO2. However, the effect of the surface structure on ER treatment remains ambiguous. In this work, three kinds of nanostructured rutile TiO2 (nanowire arrays (TNWs), etched nanowire arrays (E-TNWs) and nanorod arrays (TNRs)) were reduced electrochemically to explore the factors influencing the ER process of rutile TiO2. The experimental results show that alkaline environment (1 M NaOH) is more conducive to the occurrence of ER reaction. And the reduced three kinds of nanostructured TiO2 photoanodes show a significantly higher photocurrent density of about 1.46, 1.65 and 1.45 mA cm−2 at 1.23 V vs. relative hydrogen electrode (RHE), respectively, which are 15, 16 and 1.1 times that of pristine TiO2. The different degrees of photocurrent density enhancement can be ascribed to the different degrees of electrochemical reduction of TiO2 with different crystallinity and exposed crystal facets as well as specific surface area. This study provides new insights into the mechanism of electrochemical reduction method. [ABSTRACT FROM AUTHOR]

Green hydrogen production from water is one attractive route to non-fossil fuel and a potential source of clean energy. Hydrogen is not only a zero-carbon energy source but can also be utilized as an efficient storage of electrical energy generated through various other sources, such as wind and solar. Cost-effective and environmentally benign direct hydrogen production through neutral water (∼pH 7) reduction is particularly challenging due to the low concentration of protons. There is currently a major need for easy-to-prepare, robust, as well as active electrode materials. Herein we report three new molecular electrodes that were prepared by anchoring commercially available, and environmentally benign cobalt-containing electrocatalysts with three different ligand frameworks (porphyrin, phthalocyanine, and corrin) on a structurally modified graphite foil surface. Under the studied reaction conditions (over 7 h at 22°C), the electrode with Co-porphyrin is the most efficient for the water reduction with starting ∼740 mV onset potential (OP) (vs. RHE, current density 2.5 mA/cm2) and a Tafel slope (TS) of 103 mV/dec. It is followed by the molecular electrodes having Co-phthalocyanine [825 mV (OP), 138 mV/dec (TS)] and Vitamin-B12 (Co-corrin moiety) [830 mV (OP), 194 mv/dec (TS)]. A clear time-dependent improvement (>200 mV over 3 h) in the H2 production overpotential with the Co-porphyrin-containing cathode was observed. This is attributed to the activation due to water coordination to the Co-center. A long-term chronopotentiometric stability test shows a steady production of hydrogen from all three cathode surfaces throughout seven hours, confirmed using an H2 needle sensor. At a current density of 10 mA/cm2, the Co-porphyrin-containing electrode showed a TOF value of 0.45 s−1 at 870 mV vs. RHE, whereas the Co-phthalocyanine and Vitamin-B12-containing electrodes showed 0.37 and 0.4 s−1 at 1.22 V and 1.15 V (vs. RHE), respectively. [ABSTRACT FROM AUTHOR]

Surface engineering of BiVO4 photoanodes is effective and feasible for photoelectrochemical (PEC) water splitting. To achieve superior PEC performance, however, more than one surface engineering method is usually indispensable, for which a positive synergistic effect is vital and thus highly desired. Herein, it is reported that the incorporation of borate moieties into ultrathin p‐type NiOx catalysts can induce the reconfiguration of surface catalytic sites to form new highly active species, in addition to enhanced fast charge separation and transfer. The photocurrent density of BiVO4 photoanodes is enhanced from 1.49 to 5.76 mA cm−2 at 1.23 V versus reversible hydrogen electrode (RHE) under AM 1.5G illumination, which is achieved by successive modifications of NiOx and borate moieties. It is found that BO3 groups anchored to Ni atoms by replacing the surface hydroxyl sites of NiOx catalysts not only increase the relative ratio of Ni3+ species to facilitate charge transfer but also provide efficient active sites for H2O molecule adsorption and oxidation reactions. This work demonstrates the positive synergistic effect of these two surface engineering methods and provides an effective pathway to construct highly efficient and stable photoanodes for PEC water splitting. [ABSTRACT FROM AUTHOR]

The construction of efficient and durable multifunctional electrodes for industrial‐scale hydrogen production presents a main challenge. Herein, molybdenum‐modulated phosphorus‐based catalytic electrodes (Mo‐NiP@NF) are prepared via mild electroless plating. Heteroatoms doping or heterostructures construction can reconfigure the intrinsic electronic structure of the pre‐catalyst and optimizes the key intermediates adsorption. Moreover, the (hypo/meta‐)phosphite anions (POxδ−) and molybdate ions (MoOxδ−) on the electrode surface of Mo‐NiP@NF afford resistance to chloride (Cl−) corrosion. Mo‐NiP@NF exhibits ultralow overpotentials of 278/550 and 282/590 mV at 1 A cm−2 during the hydrogen/oxygen evolution reaction (HER/OER) in alkaline simulated and real seawater, respectively, whereas catalytic overall seawater splitting (OWS) reach 1 A cm−2 at 1.96 and 1.97 Vcell. Remarkably, Mo‐NiP@NF maintains stable operation for 1500 h in OWS. The scalability of Mo‐NiP@NF allowing the assembly of proton exchange membrane (PEM) electrolyzer powered by photovoltaic energy, simulating a portable hydrogen‐oxygen respirator provides an oxygen/hydrogen flows of 160/320 mL min−1. Expanding further, the trace ruthenium‐loaded Mo‐NiP@NF catalyst sodium borohydride (NaBH4) hydrolysis achieving a hydrogen generation rate (HGR) of 11049.2 mL min−1 g−1. This work provides strategic innovations and optimization solutions for the economical and mild construction of multi‐scenario durable green energy conversion materials at industrial‐scale application. [ABSTRACT FROM AUTHOR]

Regulating the adsorption of an intermediate on an electrocatalyst by manipulating the electron spin state of the transition metal is of great significance for promoting the activation of inert nitrogen molecules (N2) during the electrocatalytic nitrogen reduction reaction (eNRR). However, achieving this remains challenging. Herein, a novel 2D/2D Mott–Schottky heterojunction, Co9S8/Nb2CTx‐P, is developed as an eNRR catalyst. This is achieved through the in situ growth of cobalt sulfide (Co9S8) nanosheets over a Nb2CTx MXene using a solution plasma modification method. Transformation of the Co spin state from low (t2g6eg1) to high (t2g5eg2) is achieved by adjusting the interface electronic structure and sulfur vacancy of Co9S8/Nb2CTx‐P. The adsorption ability of N2 is optimized through high spin Co(II) with more unpaired electrons, significantly accelerating the *N2→*NNH kinetic process. The Co9S8/Nb2CTx‐P exhibits a high NH3 yield of 62.62 µg h−1 mgcat.−1 and a Faradaic efficiency (FE) of 30.33% at −0.40 V versus the reversible hydrogen electrode (RHE) in 0.1 m HCl. Additionally, it achieves an NH3 yield of 41.47 µg h−1 mgcat.−1 and FE of 23.19% at −0.60 V versus RHE in 0.1 m Na2SO4. This work demonstrates a promising strategy for constructing heterojunction electrocatalysts for efficient eNRR. [ABSTRACT FROM AUTHOR]

Substituting thermodynamically favorable ethanol oxidation reaction (EOR) for oxygen evolution reaction (OER) engenders high‐efficiency hydrogen production and generates high value‐added products as well. However, the main obstacles have been the low activity and the absence of an explicit catalytic mechanism. Herein, a heterostructure composed of amorphous vanadium oxide and crystalline nickel nitride (VOx−Ni3N) is developed. The heterostructure immensely boosts the EOR process, achieving the current density of 50 mA cm−2 at the low potential of 1.38 V versus reversible hydrogen electrode (RHE), far surpassing the sluggish OER (1.65 V vs RHE). Electrochemical impedance spectroscopy indicates that the as‐fabricated heterostructure can promote the adsorption of OH− and the generation of the reactive species (O*). Theoretical calculations further outline the dual polarization of the Ni site at the interface, specifically the asymmetric charge redistribution (interfacial polarization) and in‐plane polarization. Consequently, the dual polarization modulates the d‐band center, which in turn regulates the adsorption/desorption strength of key reaction intermediates, thereby facilitating the entire EOR process. Moreover, a VOx−Ni3N‐based electrolyzer, coupling hydrogen evolution reaction (HER) and EOR, attains 50 mA cm−2 at a low cell voltage of ≈1.5 V. This work thus paves the way for creating dual polarization through interface engineering toward broad catalysis. [ABSTRACT FROM AUTHOR]