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In this study, a general and effective phosphorization strategy is successfully demonstrated to enhance supercapacitor performance of various transition metals oxide or hydroxide, such as Ni(OH)2, Co(OH)2, MnO2, and Fe2O3. For example, a 3D networked Ni2P nanosheets array via a facile phosphorization reaction of Ni(OH)2 nanosheets is grown on the surface of a Ni foam. The Ni foam-supported Ni2P nanosheet (Ni2P NS/NF) electrode shows a remarkable specific capacitance of 2141 F g−1 at a scan rate of 50 mV s−1 and remains as high as 1109 F g−1 even at the current density of 83.3 A g−1. The specific capacitance is much larger than those of Ni(OH)2 NS/NF (747 F g−1 at 50 mV s−1). Furthermore, the electrode retains a high specific capacitance of 1437 F g−1 even after 5000 cycles at a current density of 10 A g−1, in sharp contrast with only 403 F g−1 of Ni(OH)2 NS/NF at the same current density. The similar enhanced performance is observed for Ni2P powder, which eliminates the influence of nickel foam. The enhanced supercapacitor performances are attributed to the 3D porous nanosheets network, enhanced conductivity, and two active components of Ni2+ and Pδ− with rich valences of Ni2P. [ABSTRACT FROM AUTHOR]

Highly active and multifunctional non‐precious metal‐based hydrogen evolution reaction (HER) eletcrocatalysts have aroused great interest in the large‐scale conversion of sustainable electrical energy to fuels and feedstocks in different application scenarios. Here, a metal sulfide‐based super hybrid nanoarray composed of a metallic Co3S4 nanosheet, P doped WS2 nanosheet, and Co9S8 nanoparticles (Super‐Co3S4/P‐WS2/Co9S8) for all‐pH HER is reported. The Super‐Co3S4/P‐WS2/Co9S8 only requires 58, 70, and 129 mV in alkaline, acid, and neutral media, respectively, to reach 10 mA cm‐2, which also presents fast reaction kinetics and high long‐term stability. The experimental and density functional theory (DFT) results verify that the abundant active heterostructure in Super‐Co3S4/P‐WS2/Co9S8 can not only provide Pt‐like H*‐adsorption Gibbs free energy (ΔGH*) but also promote the H2O adsorption and dissociation kinetics for all‐pH HER. Moreover, the collaboration of favorable metallic components and special nanoarray morphology can also strengthen the electric conductivity for electron transfer and promote the maximum exposure of active heterointerfaces for mass transport in electrocatalysis. The interesting strategy herein is expected to inspire the future design of advanced metal sulfide‐based heterostructures for energy storage and conversion. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting for the production of hydrogen proves to be effective and available. In general, the thermal radiation synthesis usually involves a slow heating and cooling process. Here, a high‐frequency induction heating (IH) is employed to rapidly prepare various self‐supported electrocatalysts grown on Ni foam (NF) in liquid‐ and gas‐phase within 1–3 min. The NF not only serves as an in situ heating medium, but also as a growth substrate. The as‐synthesized Ni nanoparticles anchored on MoO2 nanowires supported on NF (Ni‐MoO2/NF‐IH) enable catalysis of hydrogen evolution reaction (HER), showing a low overpotential of −39 mV (10 mA cm−2) and maintaining the stability of 12 h in alkaline condition. Moreover, the NiFe layered double hydroxide (NiFe LDH/NF‐IH) is also synthesized via IH and affords outstanding oxygen evolution reaction (OER) activity with an overpotential of 246 mV (10 mA cm−2). The Ni‐MoO2/NF‐IH and NiFe LDH/NF‐IH are assembled to construct a two‐electrode system, where a small cell voltage of ≈1.50 V enables a current density of 10 mA cm−2. More importantly, this IH method is also available to rapidly synthesize other freestanding electrocatalysts on NF, such as transition metal hydroxides and metal nitrides. [ABSTRACT FROM AUTHOR]

Abstract: Development of electrocatalysts for hydrogen evolution reaction (HER) with low overpotential and robust stability remains as one of the most serious challenges for energy conversion. Herein, a serviceable and highly active HER electrocatalyst with multilevel porous structure (Co‐Co2P nanoparticles@N, P doped carbon/reduced graphene oxides (Co‐Co2P@NPC/rGO)) is synthesized by Saccharomycete cells as template to adsorb metal ions and graphene nanosheets as separating agent to prevent aggregation, which is composed of Co‐Co2P nanoparticles with size of ≈104.7 nm embedded into carbonized Saccharomycete cells. The Saccharomycete cells provide not only carbon source to produce carbon shells, but also phosphorus source to prepare metal phosphides. In order to realize the practicability and permanent stability, the binderless and 3D electrodes composed of obtained Co‐Co2P@NPC/rGO powder are constructed, which possess a low overpotential of 61.5 mV (achieve 10 mA cm−2) and the high current density with extraordinary catalytic stability (1000 mA cm−2 for 20 h) in 0.5 m H2SO4. The preparation process is appropriate for synthesizing various metal or metal phosphide@carbon electrocatalysts. This work may provide a biological template method for rational design and fabrication of various metals or metal compounds@carbon 3D electrodes with promising applications in energy conversion and storage. [ABSTRACT FROM AUTHOR]

Although numerous ruthenium‐based phosphates possess high catalytic activities for hydrogen evolution reaction (HER), most of them rely on dangerous and toxic synthesis routes. Biological slices confirm that Ru ions can penetrate the cell walls of saccharomycete, which facilitates the adsorption of Ru ions. Herein, based on a green synthesis process by saccharomycete cells as the carbon template and nitrogen/phosphorus (N/P) sources, novel Janus‐like ruthenium–ruthenium phosphide nanoparticles embedded into a N/P dual‐doped carbon matrix (Ru–Ru2PΦNPC) electrocatalyst for HER are synthesized. Electrochemical tests reveal that Ru–Ru2PΦNPC displays remarkable performance with a low overpotential of 42 mV at 10 mA cm−2 and demonstrates superior stability at a high current density in 0.5 m H2SO4. Furthermore, ruthenium oxide nanoparticles coated N/P dual‐doped carbon (NPC@RuO2) are also synthesized with a yolk–shell structure using saccharomycete cells as the core template and RuO2 as a shell to isolate saccharomycete cells from the oxidation reaction during calcination in air. The NPC@RuO2 as oxygen evolution reaction electrocatalyst possesses a low overpotential of 220 mV at 10 mA cm−2. Finally, the Ru–Ru2PΦNPC is integrated as a cathode and NPC@RuO2 is integrated as an anode to construct a two‐electrode electrolyzer to enable an excellent performance for overall water splitting with a cell voltage of 1.50 V at 10 mA cm−2 in 0.5 m H2SO4. [ABSTRACT FROM AUTHOR]