General Design of Aligned-Channel Porous Carbon Electrodes for Efficient High-Current-Density Gas-Evolving Electrocatalysis.

Gas-evolving reactions (GERs) are important in many electrochemical energy conversion technologies and chemical industries. The operation of GERs at high current densities is critical for their industrial implementation but remains challenging as it poses stringent requirements on the electrodes in terms of reaction kinetics, mass transfer, and electron transport. Here the general and rational design of self-standing carbon electrodes with vertically aligned porous channels, appropriate pore size distribution, and high surface area as supports for loading a variety of catalytic species by facile electrodeposition are reported. These electrodes simultaneously possess high intrinsic activity, large numbers of active sites, and efficient transport highways for ions, gases, and electrons, resulting in significant performance improvements at high current densities in diverse GERs such as urea oxidation, hydrogen evolution, and oxygen evolution reactions, as well as overall urea/water electrolyzers. As an example, the carbon electrode decorated with Ni(OH)2 demonstrates a record-high current density of 1000 mA cm-2 at 1.360 V versus the reversible hydrogen electrode, largely outperforming the conventional nickel foam-based counterpart and the state-of-the-art electrodes.

Mo Migration-Induced Crystalline to Amorphous Conversion and Formation of RuMo/NiMoO4 Heterogeneous Nanoarray for Hydrazine-Assisted Water Splitting at Large Current Density.

Manipulating the atomic structure of the catalyst and tailoring the dissociative water-hydrogen bonding network at the catalyst-electrolyte interface is essential for propelling alkaline hydrogen evolution reactions (HER) and hydrazine oxidation reaction (HzOR), but remains a great challenge. Herein, we constructed an advanced a-RuMo/NiMoO4/NF heterogeneous electrocatalysts with amorphous RuMo alloy nanoclusters anchored to amorphous NiMoO4 skeletons on Ni foam by a heteroatom implantation strategy. Theoretical calculations and in-situ Raman tests show that the amorphous and alloying structure of a-RuMo/NiMoO4/NF not only induces the directional evolution of interfacial H2O, but also lowers the d-band center (from -0.43 to -2.22 eV) of a-RuMo/NiMoO4/NF, the Gibbs free energy of hydrogen adsorption (ΔGH*, from -1.29 to -0.06 eV), and the energy barrier of HzOR (ΔGN2(g) = 1.50 eV to ΔGN2* = 0.47 eV). Profiting from these favorable factors, the a-RuMo/NiMoO4/NF exhibits excellent electrocatalytic performances, especially at large current densities, with an overpotential of 13 and 129 mV to reach 10 and 1000 mA cm-2 for HER. While for HzOR, it needs only -91 and 276 mV to deliver 10 and 500 mA cm-2, respectively. Further, the constructed a-RuMo/NiMoO4/NF||a-RuMo/NiMoO4/NF electrolyzer demands only 7 and 420 mV to afford 10 and 500 mA cm-2.

Near 100% Conversion of Acetylene to High-purity Ethylene at Ampere-Level Current.

Direct production of high-purity ethylene from acetylene using renewable energy through electrocatalytic semi-hydrogenation presents a promising alternative to traditional thermocatalytic processes. However, the low conversion of acetylene results in a significant amount of acetylene impurities in the product, necessitating additional purification steps. Herein, a tandem electrocatalytic system that integrates acetylene electrolyzer and zinc-acetylene battery units for high-purity ethylene production is designed. The ultrathin CuO nanoribbons with enriched oxygen vacancies (CuO1-x NRs) as electrocatalysts achieve a remarkable 93.2% Faradaic efficiency of ethylene at an ampere-level current density of 1.0 A cm-2 in an acetylene electrolyzer, and the power density reaches 3.8 mW cm-2 in a zinc-acetylene battery under acetylene stream. Moreover, the tandem electrocatalysis system delivers a single-pass acetylene conversion of 99.998% and ethylene selectivity of 96.1% at a high current of 1.4 A. Experimental data and calculations demonstrate that the presence of oxygen vacancies accelerates water dissociation to produce active hydrogen atoms while preventing the over-hydrogenation of ethylene. Furthermore, techno-economic analysis reveals that the tandem system can dramatically reduce the overall ethylene production cost compared to the conventional thermocatalytic processes. A novel strategy for complete acetylene-to-ethylene conversion under mild conditions, establishing a non-petroleum route for the production of ethylene is reported.

Electronic Structure Regulation by Fe Doped Ni-Phosphides for Long-term Overall Water Splitting at Large Current Density.

Acquiring a highly efficient electrocatalyst capable of sustaining prolonged operation under high current density is of paramount importance for the process of electrocatalytic water splitting. Herein, Fe-doped phosphide (Fe-Ni5P4) derived from the NiFc metal-organic framework (NiFc-MOF) (Fc: 1,1'-ferrocene dicarboxylate) shows high catalytic activity for overall water splitting (OWS). Fe-Ni5P4||Fe-Ni5P4 exhibits a low voltage of 1.72 V for OWS at 0.5 A cm-2 and permits stable operation for 2700 h in 1.0 m KOH. Remarkably, Fe-Ni5P4||Fe-Ni5P4 can sustain robust water splitting at an extra-large current density of 1 A cm-2 for 1170 h even in alkaline seawater. Theoretical calculations confirm that Fe doping simultaneously reduces the reaction barriers of coupling and desorption (O*→OOH*, OOH*→O2 *) in the oxygen evolution reaction (OER) and regulates the adsorption strength of the intermediates (H2O*, H*) in the hydrogen evolution reaction (HER), enabling Fe-Ni5P4 to possess excellent dual functional activity. This study offers a valuable reference for the advancement of highly durable electrocatalysts through the regulation derived from coordination frameworks, with significant implications for industrial applications and energy conversion technologies.

Bimetallic Sulfide Sb2S3/FeS2 Heterostructure Anchored in a Carbon Skeleton for Fast and Stable Sodium Storage.

Sodium-ion batteries (SIBs) are a promising substitute for lithium batteries due to their abundant resources and low cost. Metal sulfides are regarded as highly attractive anode materials due to their superior mechanical stability and high theoretical specific capacity. Guided by the density functional theory (DFT) calculations, 3D porous network shaped Sb2S3/FeS2 composite materials with reduced graphene oxide (rGO) through a simple solvothermal and calcination method, which is predicted to facilitate favorable Na+ ion diffusion, is synthesized. Benefiting from the well-designed structure, the resulting Sb2S3/FeS2 exhibit a remarkable reversible capacity of 536 mAh g-1 after 2000 cycles at a current density of 5 A g-1 and long high-rate cycle life of 3000 cycles at a current density of 30 A g-1 as SIBs anode. In situ and ex situ analyses are carried out to gain further insights into the storage mechanisms and processes of sodium ions in Sb2S3/FeS2@rGO composites. The significantly enhanced sodium storage capacity is attributed to the unique structure and the heterogeneous interface between Sb2S3 and FeS2. This study illustrates that combining rGO with heterogeneous engineering can provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs.

Enhancing the Electrocatalytic Oxidation of 5-Hydroxymethylfurfural Through Cascade Structure Tuning for Highly Stable Biomass Upgrading.

Electrocatalytic 5-hydroxymethylfurfural oxidation reaction (HMFOR) provides a promising strategy to convert biomass derivative to high-value-added chemicals. Herein, a cascade strategy is proposed to construct Pd-NiCo2O4 electrocatalyst by Pd loading on Ni-doped Co3O4 and for highly active and stable synergistic HMF oxidation. An elevated current density of 800 mA cm-2 can be achieved at 1.5 V, and both Faradaic efficiency and yield of 2,5-furandicarboxylic acid remained close to 100% over 10 consecutive electrolysis. Experimental and theoretical results unveil that the introduction of Pd atoms can modulate the local electronic structure of Ni/Co, which not only balances the competitive adsorption of HMF and OH- species, but also promote the active Ni3+ species formation, inducing high indirect oxidation activity. We have also discovered that Ni incorporation facilitates the Co2+ pre-oxidation and electrophilic OH* generation to contribute direct oxidation process. This work provides a new approach to design advanced electrocatalyst for biomass upgrading.

Inducing a Synergistic Effect on Ptδ+/Electron-Rich Sites via a Platinization Strategy: Generating Hyper-High Current Density in Hydrogen Evolution Reaction.

Herein, we propose a platinization strategy for the preparation of Pt/X catalysts with low Pt content on substrates possessing electron-rich sites (Pt/X: X = Co3O4, NiO, CeO2, Covalent Organic Framework (COF), etc.). In examples with inorganic and organic substrates, respectively, Pt/Co3O4 possesses remarkable catalytic ability toward HER, achieving a current density at an overpotential of 500 mV that is 3.22 times higher than that of commercial Pt/C. It was also confirmed by using operando Raman spectroscopy that the enhancement of catalytic activity was achieved after platinization of the COF, with a reduction of overpotential from 231 to 23 mV at 10 mA cm-2. Density functional theory (DFT) reveals that the improved catalytic activity of Pt/Co3O4 and Pt/COF originated from the re-modulation of Ptδ+ on the electronic structure and the synergistic effect of the interfacial Ptδ+/electron-rich sites. This work provides a rapid synthesis strategy for the synthesis of low-content Pt catalysts for electrocatalytic hydrogen production.

Nitrosamine formation driven by electrochemical chlorination of urine-containing source waters: Effects of operational conditions.

We investigated the formation of nitrosamines from urine during electrochemical chlorination (EC) using dimensionally stable anodes. Short-term electrolysis (< 1 h) of urine at 25 mA cm-2 generated seven nitrosamines (0.1-7.4 µg L-1), where N-nitrosodimethylamine, N-nitrosomethylethylamine, and N-nitrosodiethylamine were predominant with concentrations ranging from 1.2 to 7.4 µg L-1. Mechanistic studies showed that the formation kinetics of nitrosamines was influenced by urine aging and composition, with fresh urine generating the highest levels (0.9-5.8 µg L-1) compared with aged, centrifuged, or filtered urine (0.2-4.1 µg L-1). Concurrently, studies on urine pretreatment through filtration and centrifugation underscored the significance of nitrogenous metabolites (such as protein-like products and urinary amino acids) and particle-associated humic fractions in nitrosamine formation during EC of urine. This finding was confirmed through chromatographic and spectroscopic studies utilizing LCOCD, Raman spectra, and 3DEEM fluorescence spectra. Parametric studies demonstrated that the ultimate [nitrosamines] increased at a pH range of 4.5-6.2, and with increasing [bromide], [ammonium], and current density. Conversely, sulfate and carbonate ions inhibited nitrosamine formation. Moreover, the implications of EC in urine-containing source waters were evaluated. The results indicate that regardless of the urine source (individual volunteers, septic tank, swimming pool, untreated municipal wastewater), high levels of nitrosamines (0.1-17.6 µg L-1) were generated, surpassing the potable reuse guideline of 10 ng L-1. Overall, this study provides insights to elucidate the mechanisms underlying nitrosamine formation and optimize the operating conditions. Such insights facilitate suppressing the generation of nitrosamine byproducts during electrochemical treatment of urine-containing wastewater.

Low-Resistance Membrane vs. High-Resistance Membrane Performance Utilizing Electrodialysis-Evaporator Hybrid System in Treating Reject Brine from Kuwait Desalination Plants.

This work is an effort to mitigate the existing environmental issues caused by brine discharge from Kuwait's desalination plants and to find an economical and efficient way of managing reject brine from local desalination plants. Low- and high-resistance membranes (LRMs and HRMs, respectively) were used to produce salt and low-salinity water from brine effluent utilizing an electrodialysis (ED)-evaporator hybrid system. The effect of high current densities of 300, 400, and 500 A/m2 and brine flowrates of 450 and 500 L/h on the quality of produced salt and diluate were investigated for LRM and HRM. The recovered salt purity for LRM is up to 90.58%. Results show that the low-resistance membrane (LRM) achieved higher water recovery, energy consumption, desalination rate, operation time and ion removal rate than those of the high-resistance membrane (HRM) under the same operating conditions. The difference in concentration for 300 A/m2 between LRM and HRM increased from 0.93% at 10 min to 8.28% at 140 min. The difference in diluate concentration effluent is negligible for both membranes, whereas LRM produced higher concentrate effluent than HRM for all current densities and low flowrate (400 L/h). The maximum difference between LRM and HRM (with LRM achieving higher concentrations) is 10.7% for 400 A/m2. The permselectivity of LRM for monovalent cations decreased with current density, whereas the effect on permselectivity for HRM was insignificant for the current density values. The addition of a neutral cell was effective in reducing the buildup of divalent ions on the inner membrane of the cathode side.

Toward Thin-Film Laser Diodes with Metal Halide Perovskites.

Metal halide perovskite semiconductors hold a strong promise for enabling thin-film laser diodes. Perovskites distinguish themselves from other non-epitaxial media primarily through their ability to maintain performance at high current densities, which is a critical requirement for achieving injection lasing. Coming in a wide range of varieties, numerous perovskites delivered low-threshold optical amplified spontaneous emission and optically pumped lasing when combined with a suitable optical cavity. A progression toward electrically pumped lasing requires the development of efficient light-emitting structures with reduced optical losses and high radiative efficiency at lasing-level current densities. This involves a set of important trade-offs in terms of material choice, stack and waveguide design, as well as resonator integration. In this Perspective, the key milestones are highlighted that have been achieved in the study of passive optical waveguides and light-emitting diodes, and these learnings are translated toward more complex laser diode architectures. Finally, a novel resonator integration route is proposed that is capable of relaxing optical and electrical design constraints.

Engineering d-p Orbital Hybridization in Mo-O Species of Medium-Entropy Metal Oxides as Highly Active and Stable Electrocatalysts toward Ampere-Level Water/Seawater Splitting.

Optimizing the electronic structure of electrocatalysts is of particular importance to enhance the intrinsic activity of active sites in water/seawater. Herein, a series of medium-entropy metal oxides of X(NiMo)O2/NF (X = Mn, Fe, Co, Cu and Zn) is designed via a rapid carbothermal shocking method. Among them, the optimized medium-entropy metal oxide (FeNiMo)O2/NF delivered remarkable HER performance, where the overpotentials as low as 110 and 141 mV are realized at 1000 mA cm-2 (@60 °C) in water and seawater. Meanwhile, medium-entropy metal oxide (FeNiMo)O2/NF only required overpotentials of as low as 330 and 380 mV to drive 1000 mA cm-2 for OER in water and seawater (@60 °C). Theoretical calculations showed that the multiple-metal synergistic effect in medium-entropy metal oxides can effectively enhance the d-p orbital hybridization of Mo─O bond, reduce the energy barrier of H* adsorbed at the Mo sites. Meanwhile, Fe sites in medium-entropy metal oxide can act as the real OER active center, resulting in a good bifunctional activity. In all, this work provides a feasible strategy for the development of highly active and stable medium-entropy metal oxide electrocatalysts for ampere-level water/seawater splitting.

Class II (three-layer system) phenomenological model based on limiting current density and dynamic chelation chemistry for separation of rare earth elements using electrodialysis.

This paper presents an in-depth investigation into the optimization of rare earth element (REE) separation through electrodialysis, leveraging a newly developed Class II phenomenological model. This study explores the pivotal roles of the HEDTA/Nd molar ratio and pH of feed solution on enhancing the separation efficiency of neodymium (Nd) and praseodymium (Pr) from lanthanum (La) and cerium (Ce). By integrating expanded Nernst-Planck equations and the concept of limiting current density, the model offers a sophisticated understanding of ion transport dynamics and the impacts of concentration polarization. Experimental validation confirms the model's predictive accuracy, demonstrating its practical applicability for industrial-scale operations. The research delineates how operational parameters such as chelating agent concentration and pH critically influence the purity and yield of separated REEs. The dynamic nature of chelation chemistry is also examined, highlighting its evolution during the electrodialysis process and its effect on the system's overall performance. Key findings illustrate that lower HEDTA/Nd molar ratios significantly enhance the purity of Nd + Pr by minimizing the chelation of La and Ce, thus facilitating their migration to the concentrate compartment. Conversely, higher ratios maximize yield by retaining more Nd + Pr in the feed compartment. This dual approach allows for optimized separation based on specific industrial requirements. The outcomes of this study not only advance the field of REE separation but also provide a framework for further research into more efficient and sustainable extraction methods. The developed model and its validation represent a step forward in the practical application of electrodialysis in REE processing, offering substantial benefits for the critical materials sector.

Unravelling the origin of the reward positivity: a human intracranial event-related brain potential study.

The reward positivity (RewP) is an event-related brain potential (ERP) component that emerges approximately 250 to 350 milliseconds (ms) after receiving reward-related feedback stimuli and is believed to be important for reinforcement learning and reward processing. Although numerous localization studies have indicated that the anterior cingulate cortex (ACC) is the neural generator of this component, other studies have identified sources outside of the ACC, fuelling a debate about its origin. Because the results of EEG and MEG source localization studies are severely limited by the inverse problem, we addressed this question by leveraging the high spatial and temporal resolution of intracranial EEG. We predicted that we would identify a neural generator of the RewP in the caudal ACC. We recorded intracranial EEG in 19 refractory epilepsy patients who underwent invasive video-EEG monitoring at Ghent University Hospital, Belgium. Participants engaged in the virtual T-maze task (vTMT), a trial-and-error task known to elicit a canonical RewP, while scalp and intracranial EEG were simultaneously recorded. The RewP was identified using a difference wave approach for both scalp and intracranial EEG. The data were aggregated across participants to create a virtual "meta-participant" that contained all the recorded intracranial ERPs (iERPs) with respect to their intracranial contact locations. We used both a hypothesis-driven (focused on ACC) and exploratory (whole-brain analysis) approach to segment the brain into regions of interest (ROI). For each ROI, we evaluated the degree to which the time course of the absolute current density (ACD) activity mirrored the time course of the RewP, and confirmed the statistical significance of the results using permutation analysis. The grand average waveform of the scalp data revealed a RewP at 309 ms after reward feedback with a frontocentral scalp distribution, consistent with the identification of this component as the RewP. The meta-participant contained iERPs recorded from 582 intracranial contacts in total. The ACD activity of the aggregated iERPs were most similar to the RewP in left caudal ACC, left dorsolateral prefrontal cortex, left frontomedial cortex, and left white matter, with the highest score attributed to caudal ACC, as predicted. To our knowledge, this is the first study that uses intracranial EEG aggregated across multiple human epilepsy patients and current source density analysis to identify the neural generator(s) of the RewP. These results provide direct evidence that the ACC is a neural generator of the RewP.

Dual Hydrogen Production System: Synergistic Effect of Ru and Ce Over Cu2O Nanotubes Drives Hydrogen Evolution and Formaldehyde Oxidation.

Water splitting for hydrogen production is limited by high cell voltage and low energy conversion efficiencies due to the slow kinetic process of the oxygen evolution reaction (OER). Here, an electrolytic system is constructed in which the cathode and anode co-release H2 at ultra-low input voltage using formaldehyde oxidation reaction (FOR) instead of OER. The prepared RuCe co-doped Cu2O nanotubes on copper foam (RuCe-Cu2O/CF) are used as electrode materials for the HER-FOR system. A current density of 0.8 A cm-2 is achieved at 0.55 V, and a stable hydrogen production process is realized at both the cathode and anode. Density functional theory (DFT) studies show that the synergistic effect of Ru and Ce drives: i) the d-band center of RuCe-Cu2O/CF away from the Fermi energy level; ii) the energy barrier for the C─H cracking of the H2C(OH)O* intermediate in FOR is lowered, which promotes the formation of H2 from H*, and iii) ΔGH* tends to 0 (-0.1 eV), optimizing the reaction kinetics of HER. This work provides a new design for an efficient catalyst for dual hydrogen production systems from water splitting.

Multi-metal ferrite as a promising catalyst for oxygen reduction reaction in microbial fuel cell.

Improving catalytic activity of cathode with noble metal-free catalysts can significantly establish microbial fuel cells (MFCs) as a sustainable and economically affordable technology. This investigation aimed to assess the viability of utilizing tri-metal ferrite (Co0.5Cu0.5 Bi0.1Fe1.9O4) as an oxygen reduction reaction (ORR) catalyst to enhance the performance of cathode in MFCs. Trimetallic ferrite was synthesized using a sol-gel auto-combustion process. Electrochemical evaluations were conducted to assess the efficacy of as-synthesized composite as an ORR catalyst, employing electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This evaluation revealed that the impregnation of bismuth in the Co-Cu-ferrite structure improves the reduction current response and reduces the charge transfer resistance. Further experiments were conducted to test the performance of this catalyst in an MFC. The MFC with tri-metal ferrite catalyst generated a power density of 11.44 W/m3 with 21.4% coulombic efficiency (CE), which was found to be comparable with commercially available 10% Pt/C used as cathode catalyst in MFC (power density of 12.14 W/m3 and CE of 23.1%) and substantially greater than MFC having bare carbon felt cathode without any catalyst (power density of 2.49 W/m3 and CE of 7.39%). This exceptionally inexpensive ORR catalyst has adequate merit to replace commercial costlier platinum-based cathode catalysts for upscaling MFCs.

Complementary Multisite Turnover Catalysis toward Superefficient Bifunctional Seawater Splitting at Ampere-Level Current Density.

The utilization of seawater for hydrogen production via water splitting is increasingly recognized as a promising avenue for the future. The key dilemma for seawater electrolysis is the incompatibility of superior hydrogen- and oxygen-evolving activities at ampere-scale current densities for both cathodic and anodic catalysts, thus leading to large electric power consumption of overall seawater splitting. Here, in situ construction of Fe4N/Co3N/MoO2 heterostructure arrays anchoring on metallic nickel nitride surface with multilevel collaborative catalytic interfaces and abundant multifunctional metal sites is reported, which serves as a robust bifunctional catalyst for alkaline freshwater/seawater splitting at ampere-level current density. Operando Raman and X-ray photoelectron spectroscopic studies combined with density functional theory calculations corroborate that Mo and Co/Fe sites situated on the Fe4N/Co3N/MoO2 multilevel interfaces optimize the reaction pathway and coordination environment to enhance water adsorption/dissociation, hydrogen adsorption, and oxygen-containing intermediate adsorption, thus cooperatively expediting hydrogen/oxygen evolution reactions in base. Inspiringly, this electrocatalyst can substantially ameliorate overall freshwater/seawater splitting at 1000 mA cm-2 with low cell voltages of 1.65/1.69 V, along with superb long-term stability at 500-1500 mA cm-2 for over 200 h, outperforming nearly all the ever-reported non-noble electrocatalysts for freshwater/seawater electrolysis. This work offers a viable approach to design high-performance bifunctional catalysts for seawater splitting.

Properties and Applications of Iron-Chalcogenide Superconductors.

Iron-chalcogenide superconductors continue to captivate researchers due to their diverse crystalline structures and intriguing superconducting properties, positioning them as both a valuable platform for theoretical investigations and promising candidates for practical applications. This review begins with a comprehensive overview of the fabrication techniques employed for various iron-chalcogenide superconductors, accompanied by a summary of their phase diagrams. Subsequently, it delves into the upper critical field, anisotropy, and critical current density. Furthermore, it discusses the successful fabrication of meters-long coated conductors and explores their applications in superconducting radio-frequency cavities and coils. Finally, several prospective avenues for future research are proposed.

Optimization of electrocoagulation process parameters for the treatment of oil industry drill site wastewater.

The effluent from the oil drilling site is a complex mixture of hazardous chemicals that causes environmental impacts on its disposal. The treatment of oil drill-site wastewater has not been explored much, and understanding its characteristics and optimizing the treatment process are required. In the present study, we have optimized the electrocoagulation process with aluminum electrodes for drill-site wastewater treatment. A multi-level factorial center composite design using response surface methodology is applied to optimize the effect of current density (CD), pH, and inter-electrode distance (IED) on chemical oxygen demand (COD) removal. The increasing current density shows a significant increase in COD removal, and a similar trend was observed with a decreased pH. It was found that with current density and inter-electrode distance, the maximum COD removal achieved was 70% at the CD of 19.04 mA cm-2 and IED 2.6 cm. By varying pH and current density, the COD removal reached up to 90% at pH 6 and CD 19.04 mA cm-2. The study shows that the current density is the dominant factor for the process's energy consumption and operating cost, followed by pH. This study's findings could be effectively used to develop large-scale treatment processes through electrocoagulation.

Boron-Doped Ti3C2Tx MXene for Effective and Durable High-Current-Density Ammonia Synthesis.

Ammonia (NH3) synthesis via the nitrate reduction reaction (NO3RR) offers a competitive strategy for nitrogen cycling and carbon neutrality; however, this is hindered by the poor NO3RR performance under high current density. Herein, it is shown that boron-doped Ti3C2Tx MXene nanosheets can highly efficiently catalyze the conversion of NO3RR-to-NH3 at ambient conditions, showing a maximal NH3 Faradic efficiency of 91% with a peak yield rate of 26.2 mgh-1 mgcat. -1, and robust durability over ten consecutive cycles, all of them are comparable to the best-reported results and exceed those of pristine Ti3C2Tx MXene. More importantly, when tested in a flow cell, the designed catalyst delivers a current density of ‒1000 mA cm-2 at a low potential of ‒1.18 V versus the reversible hydrogen electrode and maintains a high NH3 selectivity over a wide current density range. Besides, a Zn-nitrate battery with the catalyst as the cathode is assembled, which achieves a power density of 5.24 mW cm-2 and a yield rate of 1.15 mgh-1 mgcat. -1. Theoretical simulations further demonstrate that the boron dopants can optimize the adsorption and activation of NO3RR intermediates, and reduce the potential-determining step barrier, thus leading to an enhanced NH3 selectivity.

Structural engineering evoked multifunctionality in molybdate nanosheets for industrial oxygen evolution and dual energy storage devices inspired by multi-method calculations.

Structural engineering, including electronic and geometric modulations, is a good approach to improve the activity of electrocatalysts. Herein, we employed FeOOH and the second metal center Ni to modulate the electronic structure of CoMoO4 and used a low temperature solvothermal route and a chemical etching method to prepare the special hollow hierarchical structure. Based on the prediction of multi-method calculations by density functional theory (DFT) and ab initial molecular dynamics (AIMD), a series of materials were fabricated. Among them, the optimal hollow FeOOH/(Ni1Co1)MoO4 by coating (NiCo)MoO4 nanosheets on FeOOH nanotubes showed excellent performances toward high current density oxygen evolution reaction (OER) in alkaline and simulated seawater solutions, hybrid supercapacitor (HSC), and aqueous battery due to the well-controlled electronic and geometric structures. The optimal FeOOH/(Ni1Co1)MoO4 required overpotentials of 225 and 546 mV to deliver 10 and 1000 mA cm-2 current densities toward alkaline OER, and maintained a good stability for 100 h at 200 mA cm-2 with negligible attenuation. The FeOOH/(Ni1Co1)MoO4//Pt/C electrolyzer exhibited a low cell voltage of 1.52 and 1.79 V to drive 10 and 200 mA cm-2 and retained a long-term durability nearly 100 h at 1.79 V. As the electrode of energy storage devices, it possessed a specific capacity of 342 mA h g-1 at 1 A g-1. HSC and SC-type battery devices were fabricated. The assembled HSC kept a capacitance retention of 94 % after 10,000 cycles. This work provided a way to fabricate effective and stable multifunctional materials for energy storage and conversion with the aid of multi-method calculations.