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Binder plays a crucial role in constructing high‐performance electrodes for water electrolysis. While most research has been focused on advancing electrocatalysts, the application of binders in electrode design has yet to be fully explored. Herein, the in situ incorporation of polytetrafluoroethylene (PTFE) as a multifunctional binder, which increases electrochemical active sites, enhances mass transfer, and strengthens the mechanical and chemical robustness of oxygen evolution reaction (OER) electrodes, is reported. The NiFe‐LDH@PTFE/NF electrode prepared by co‐deposition of PTFE with NiFe‐layered double hydroxide onto nickel foam demonstrates exceptional long‐term stability with a minimal potential decay rate of 0.034 mV h−1 at 500 mA cm−2 for 1000 h. The alkaline water electrolyzer utilizing NiFe‐LDH@PTFE/NF requires only 1.584 V at 500 mA cm−2 and sustains high energy efficiency over 1000 h under industrial operating conditions. This work opens a new path for stabilizing active sites to obtain durable electrodes for OER as well as other electrocatalytic systems. [ABSTRACT FROM AUTHOR]

Abstract Binder plays a crucial role in constructing high‐performance electrodes for water electrolysis. While most research has been focused on advancing electrocatalysts, the application of binders in electrode design has yet to be fully explored. Herein, the in situ incorporation of polytetrafluoroethylene (PTFE) as a multifunctional binder, which increases electrochemical active sites, enhances mass transfer, and strengthens the mechanical and chemical robustness of oxygen evolution reaction (OER) electrodes, is reported. The NiFe‐LDH@PTFE/NF electrode prepared by co‐deposition of PTFE with NiFe‐layered double hydroxide onto nickel foam demonstrates exceptional long‐term stability with a minimal potential decay rate of 0.034 mV h−1 at 500 mA cm−2 for 1000 h. The alkaline water electrolyzer utilizing NiFe‐LDH@PTFE/NF requires only 1.584 V at 500 mA cm−2 and sustains high energy efficiency over 1000 h under industrial operating conditions. This work opens a new path for stabilizing active sites to obtain durable electrodes for OER as well as other electrocatalytic systems.

The widespread use of unsustainable fossil fuels has caused serious damage to the ecological environment. The development of sustainable clean energy is urgent. Producing hydrogen by water electrolysis can effectively solve fossil energy shortage and environmental pollution issues. The preparation of inexpensive, efficient, and stable electrocatalytic hydrogen evolution electrode materials is the key to achieving the application of electrocatalytic hydrogen evolution. Herein, the amorphous nickel oxide/nickel foam (NiO x /NF) hydrogen evolution electrode was prepared by a simple one-step hydrothermal method with hydrogen peroxide as an oxidant. The amorphous leaf array structure of NiO x /NF electrode can enrich the surface composition and expose more catalytic active sites. Further, hydrogen peroxide etching can optimize the electronic structure of NiO x , and accelerate the electron migration. Thus, NiO x /NF displays excellent alkaline hydrogen evolution activity with the low over potentials of 70, 318 and 361 mV at 10, 500 and 1000 mA cm−2, respectively, leading to high performance in alkaline HER than those of reported Ni-based electrodes and even surpasses commercial Pt/C at high current density. Our work provides a new approach for developing inexpensive electrocatalysts with excellent alkaline hydrogen evolution activity and stability. [Display omitted] • Amorphous NiO X /NF electrocatalyst was developed in a simple hydrothermal process with hydrogen peroxide as an etchant. • Hydrogen peroxide etching optimized the electronic structure of NiO X , and increased the electron transfer rates. • NiO X /NF exhibited admirable alkaline HER activity (η 10 of 70 mV, 68.2 mV dec-1) and excellent long-term stability. • NiO X /NF displayed obvious advantages at a practical current density of 500 mA cm-2 over commercial Pt/C. [ABSTRACT FROM AUTHOR]

Nickel–iron oxygen evolution catalysts have been under the spotlight as substitutes for precious metals, however, they rarely operate efficiently in practical industrial electrolyzers due to their moderate activity. Guided by density functional theory, the interaction of cation vacancies and dopants can manipulate d band centers, thus gaining near‐optimal binding energies of the oxygenated intermediates and ultralow potentials. This principle is implemented experimentally by catalysis operando variations synthesis, more specifically, in situ Mo leaching from high‐entropy Co, Mo co‐doped NiFe hydroxide precursors form Co dopant and cation vacancy coexistent NiFe oxyhydroxide. Operando electrochemical spectroscopy uncovers that dual‐cation‐defects promote the readier oxidation transition of metal sites, thus contributing to a low overpotential of 255 mV at 100 mA cm−2. Furthermore, dual‐regulated NiFe oxyhydroxide electrodes operate stably at 8 A in practical industrial electrolyzers with ultralow energy consumption of ≈4.6 kWh m−3 H2, verifying the feasibility of lab‐constructed novel catalysts towards industrialization. [ABSTRACT FROM AUTHOR]

It is vitally important to develop highly active, robust and low‐cost transition metal‐based electrocatalysts for overall water splitting in neutral solution especially at large current density. In this work, amorphous Mo‐doped NiS0.5Se0.5 nanosheets@crystalline NiS0.5Se0.5 nanorods (Am−Mo−NiS0.5Se0.5) was synthesized using a facil one‐step strategy. In phosphate buffer saline solution, the Am−Mo−NiS0.5Se0.5 shows tiny overpotentials of 48 and 209 mV for hydrogen evolution reaction (HER), 238 and 514 mV for oxygen evolution reaction (OER) at 10 and 1000 mA cm−2, respectively. Moreover, Am−Mo−NiS0.5Se0.5 delivers excellent stability for at least 300 h without obvious degradation. Theoretical calculations revealed that the Ni sites in the defect‐rich amorphous structure of Am−Mo−NiS0.5Se0.5 owns higher electron state density and strengthened the binding energy of H2O, which will optimize H adsorption/desorption energy barriers and reduce the adsorption energy of OER determining step. [ABSTRACT FROM AUTHOR]

Versatile catalyst systems with large current density under industrial conditions are pivotal to give impetus to hydrogen energy from fundamental to practical applications. Herein, a Schottky heterojunction nanosheet array composed of dispersed NiFe hydroxide nanoparticles and ultrathin NiS nanosheets (NiFe LDH/NiS) is proposed to regulate cooperatively mass transport and electronic structure for triggering oxygen evolution reaction (OER) activity at high current. In catalytic systems, the rich porosity of the NiS nanosheet array contributes abundant catalytic sites and good infiltration of the electrolyte for fast mass transfer. Furthermore, theoretical calculations reveal the coupling of NiFe LDH onto the NiS could tune the d‐band center of Ni(Fe) atoms and the binding strength of oxygen intermediates for favorable OER kinetics. Therefore, the NiFe LDH/NiS Schottky heterojunction exhibits a remarkable OER activity, delivering a current density of 1000 mA cm–2 at the ultralow overpotential of 325 mV. Meanwhile, scaled‐up NiFe LDH/NiS electrodes are implemented in an industrial water splitting electrolyzer and exhibit a stable cell voltage of 2.01 V to deliver a constant catalytic current of 8000 mA over 80 h, saving 0.215 kWh of electricity to generate more hydrogen per cubic meter than commercial Raney Ni electrodes. [ABSTRACT FROM AUTHOR]

A high-current-density terahertz electron-optical system based on a carbon nanotube (CNT) cold cathode has been investigated in order to solve notable mode competition in high-order harmonic gyrotrons. Simulation results show that a near-axis electron beam can be generated, with a beam current of 160 mA at an accelerating voltage of 23.5 kV. The source supports the electron beam with a velocity ratio of 1.1 and a guiding center radius of 57~μm. A narrow beam spatial distribution is evidenced by adjusting control anode voltage, satisfying the need for high operating current density in slow wave devices. The current density of the electron beam is up to 620 A/cm2 at the output port and the velocity ratio is 0.44, with parallel energy accounting for 84% of the total energy. [ABSTRACT FROM AUTHOR]

Multiphasic fish-gill-like NiCoP@Co 0.5 Ni 0.5 Se 2 heterostructure with an extremely high stability is fabricated as high performance electrocatalyst for high current density hydrogen evolution. This work provides an innovative approach to efficient electrocatalysts of industrial potential. [Display omitted] • A fish-gill-like heterostructure NiCoP@Co 0.5 Ni 0.5 Se 2 /NF is created. • Water and hydrogen adsorption kinetics are optimized. • NiCoP@Co 0.5 Ni 0.5 Se 2 /NF achieves a high-current-density of 671 mA cm−2 at 250 mV. • An excellent overall water splitting performance is realized. Multiphasic engineering is powerful to improve the performance of hydrogen evolution. Here, NiCoP@Co 0.5 Ni 0.5 Se 2 heterostructure with a fish-gill-like morphology has been initially prepared via an epitaxial controlled growth strategy. When used as catalyst in the hydrogen evolution, this heterostructure gives low overpotential of 235 mV and long-term durability of 100 h at high current density of 500 mA cm−2 in 1.0 M KOH, showing a superior activity and excellent stability. Such superior performances are achieved by its 3D multiphasic heterostructure and optimized interface electronic structure because extremely porous superhydrophilic and superaerophobic surface of hierarchical morphology enhance kinetic of hydrogen evolution. The findings reported in this work open new occasion for creating novel technologies based on nature-inspired strategy and multiphasic engineering, as evidenced by a superior overall water splitting performance of an assembled NiCoP@Co 0.5 Ni 0.5 Se 2 /NF‖NiFe-LDH/NF cell under industrial condition (30 % KOH, 25 and 60 °C). [ABSTRACT FROM AUTHOR]

Powerful, efficient, and corrosion-resistant electrocatalysts are in need to achieve high-current-density neutral seawater hydrogen evolution. Here, a novel strategy through strong metal-support interaction (SMSI) and incorporation of Pt to construct PtNb-Nb 2 O 5 clusters @C was developed with stable high-current-density neutral seawater hydrogen evolution property for the first time. SMSI prevents agglomeration and corrosion of nanomaterials. Pt sites were proposed to play an anabranch role by binding H* to stabilize the Nb valence state and prevent water dissociation incapacitation. The optimized PtNb-Nb 2 O 5 @CC delivers low overpotentials of 440 mV (500 mA cm−2) and 570 mV (1000 mA cm−2) in neutral seawater and has 360 h excellent durability at 500 mA cm−2. In-situ Fourier transform infrared spectroscopy (FTIR), in-situ Raman spectroscopies and theoretical calculations supported the hydrogen evolution reaction (HER) mechanism. PtNb-Nb 2 O 5 heterogeneous interface provided more active sites for water dissociation. OH* adsorbed on Nb sites in stable Nb 2 O 5 , and H* adsorbed on Nb sites and desorbed as H 2 on Pt sites in stable PtNb. Overall, this work not only first achieves stable high-current-density neutral seawater hydrogen evolution property, but also opens a new opportunity to explore SMSI and incorporation of Pt to prevent agglomeration, corrosion, and water dissociation incapacitation for catalytic applications under high current densities. [Display omitted] • A novel strategy through strong metal-support interaction and incorporation of Pt was proposed. • This strategy can prevent agglomeration, corrosion and water dissociation incapacitation. • PtNb-Nb 2 O 5 clusters @C was synthesized by solvent-free microwave method. • Stable high-current-density neutral seawater hydrogen evolution property was achieved. • In-situ characterizations and theoretical calculations demonstrate the reaction mechanism. [ABSTRACT FROM AUTHOR]

It is vitally important to develop highly active, robust and low-cost transition metal-based electrocatalysts for overall water splitting in neutral solution especially at large current density. In this work, amorphous Mo-doped NiS 0.5 Se 0.5 nanosheets@crystalline NiS 0.5 Se 0.5 nanorods (Am-Mo-NiS 0.5 Se 0.5 ) was synthesized using a facil one-step strategy. In phosphate buffer saline solution, the Am-Mo-NiS 0.5 Se 0.5 shows tiny overpotentials of 48 and 209 mV for hydrogen evolution reaction (HER), 238 and 514 mV for oxygen evolution reaction (OER) at 10 and 1000 mA cm -2 , respectively. Moreover, Am-Mo-NiS 0.5 Se 0.5 delivers excellent stability for at least 300 h without obvious degradation. Theoretical calculations revealed that the Ni sites in the defect-rich amorphous structure of Am-Mo-NiS 0.5 Se 0.5 owns higher electron state density and strengthened the binding energy of H 2 O, which will optimize H adsorption/desorption energy barriers and reduce the adsorption energy of OER determining step., (© 2022 Wiley-VCH GmbH.)

The scalable production of inexpensive, efficient, and robust catalysts for oxygen evolution reaction (OER) that can deliver high current densities at low potentials is critical for the industrial implementation of water splitting technology. Herein, a series of metal oxides coupled with Fe 2 O 3 are in situ grown on iron foam massively via an ultrafast combustion approach for a few seconds. Benefiting from the three-dimensional nanosheet array framework and the heterojunction structure, the self-supporting electrodes with abundant active centers can regulate mass transport and electronic structure for prompting OER activity at high current density. The optimized Ni(OH) 2 /Fe 2 O 3 with robust structure can deliver a high current density of 1000 mA cm -2 at the overpotential as low as 271 mV in 1.0 M KOH for up to 1500 h. Theoretical calculation demonstrates that the strong electronic modulation plays a crucial part in the hybrid by optimizing the adsorption energy of the intermediate, thereby enhancing the efficiency of oxygen evolution. This work proposes a method to construct cheap and robust catalysts for practical application in energy conversion and storage.

Abstract: New self-ordering porous alumina films were fabricated in organic acid electrolytes. Highly ordered cell arrangements of porous alumina films were realized in malonic acid at 120V and tartaric acid at 195V having 300nm and 500nm pore intervals, respectively. Self-organization was achieved at the maximum voltage required to induce high-current-density anodization while preventing burning, i.e., an extremely high-current flow concentrated at local points. The cells of the film grown at a high field must be pressed against each other, so that the self-ordering proceeds with the porous layer growth. When the self-ordering of cell arrangement proceeds, the cells became smaller. To improve the regularity of the cell configuration, a low electrolyte temperature and a relatively high electrolyte concentration were effective for maintaining a high-current-density to prevent burning. Surface flatness was an essential factor for self-ordering, however, the surface oxide film produced by electropolishing an aluminum substrate prevented quick pore growth in the organic acids having a low dissociation constant. It is confirmed that electropolishing followed by alkaline treatment was most appropriate as the pre-treatment in preparing flat surfaces. [Copyright &y& Elsevier]

The magneto-impedance (MI) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 wires has been measured to investigate the influence of DC annealing, high-current-density electropulsing annealing and tensile stress on it. The results show that the MI of DC annealed sample exhibits sharp maximum at Hex=Hk. Maximum MI ratio of 60% is observed in sample of high-current-density electropulsing annealed under applied tensile stress. [Copyright &y& Elsevier]