Achieving efficient and robust hydrogen evolution reaction (HER) electrocatalysts under all‐pH conditions is significant for clean hydrogen production. Herein, an ultralow Pt‐decorated hierarchical Ni‐Mo porous hybrid, consisting of Ni3Mo3N on MoO2 microcolumns, is developed for all‐pH HER with remarkable catalytic performances, owing to the porous structure, strong metal‐support interaction, along with ultralow Pt nanoparticles and multichannel nickel foam support. The superhydrophilic and aerophilic surfaces favor mass transport during the HER process. Consequently, the porous Pt/Ni‐Mo‐N‐O microcolumns present remarkable HER activity and durability with low overpotentials of 40.6, 101.1, and 89.5 mV to obtain 100 mA cm−2 in basic, neutral, and acid media, respectively. Moreover, the excellent performance in alkaline seawater (40.4 mV@100 mA cm−2) even suppresses most of over‐reported catalysts. More importantly, the two‐electrode cell, assembled with Pt/Ni‐Mo‐N‐O and NiMoO4 as cathode and anode, exhibits excellent performance towards overall‐water electrolysis with an ultralow cell voltage of 1.56 V@100 mA cm−2.

Superb All‐pH Hydrogen Evolution Performances Powered by Ultralow Pt‐Decorated Hierarchical Ni‐Mo Porous Microcolumns

The transition metal phosphides have drawn wide attention as positive material used in supercapacitors owing to the excellent conductivity and electrochemical activity. In this work, the novel composite Co(OH)F@CoP core-shell nanoarrays, used as electrode material for supercapacitors, was synthesized on conductive carbon cloth (CC) through the hydrothermal method and phosphating process. The specific capacitance of Co(OH)F@CoP/CC is 654mC cm−2 at 1 mA·cm−2, and maintains long-life cycling stability of 71.34 % retention after 10,000 cycles at 10 mA·cm−2 in a three electrode system. Furthermore, a two-electrode system assembled by Co(OH)F@CoP and reduced graphene oxide (RGO) exhibits performance with energy density of 17.933 Wh kg−1 at power density of 800 W kg−1. These results proved that the Co(OH)F@CoP composite is an advanced electrode material for the supercapacitors. 

Co(OH)F@CoP/CC core-shell nanoarrays for high-performance supercapacitors

In this work, uniform CuCo2O4 nanowires (CCO-NWs) and nanosheets (CCO-NSs) were directly grown on the stainless-steel foil via a hydrothermal process with a post calcination treatment in air, and powdered CuCo2O4 materials were obtained once they were peeled off from the stainless-steel substrate. These NWs- and NSs-based powders possessed a huge specific surface area and mesoporous feature. After electrochemical tests, it was found that the CCO-NWs delivered a capacity of 299.12 C g−1 and CCO-NSs could exhibit a capacity of up to 332.18 C g−1. A hybrid supercapacitor (HSC) was assembled with activated carbon (AC) as anode to evaluate the practical applications of CuCo2O4 in energy storage. The CCO-NWs//AC HSC exhibited an energy density of 36.16 W h kg−1 at 1.01 kW kg−1, and as for the CCO-NSs//AC HSC, it delivered 38.46 W h kg−1 at the power density of 1.03 kW kg−1. Both HSCs showed excellent cycling performance over 5000 cycles at 6 A g−1. The superior electrochemical performance of CuCo2O4 NWs and NSs indicates that the battery-type CuCo2O4 electrode materials can serve as advanced cathode for high-performance supercapacitors, and the simple synthetic method can be extended to the preparation of other transition metal oxides (TMOs)-based electrode materials with uniform structure and impressive electrochemical properties. 

Growth of uniform CuCo2O4 porous nanosheets and nanowires for high-performance hybrid supercapacitors

Layered transition metal hydroxide, a clay-like material, possessing characteristics of large specific surface area, adjustable fraction, and plentiful active components make it a potential energy storage material, especially in the background of energy and environment crisis. Herein, comprehensive applications of cobalt-aluminum-based LDHs for supercapacitors are proposed. Binder-free electrodes were successfully synthesized such as Co 3 Al 1 -LDH/Ni, Ni 2 Co 1 Al 1 -LDH/Ni and Ni 1 Co 2 Al 1 -LDH/Ni using a rapid green hydrothermal approach. Subsequently, further sulfuration was carried out to obtain a heterostructure of sulfide/layered hydroxide. The electrochemical energy storage properties of binder-free electrodes were investigated, which show that the performance of ternary LDH electrode is better than that of binary one, and the incompletely sulfuration Ni 1 Co 2 S/Ni has the optimal electrochemical performance among all electrodes, with a specific capacitance of 2186 F g −1 at 1 A g −1 . The Ni 1 Co 2 S//AG hybrid supercapacitor (HSC) device assembled with Ni 1 Co 2 S as positive electrode and active graphene as negative electrode delivers an energy density of 13 Wh kg −1 at a power density of 749 W kg −1 , good rate capability and cycling stability. • Binary and ternary NiCoAl-LDHs were successfully synthesized in situ on nickel foam with vertical structures. • Incomplete sulfuration of NiCoAl-LDH was successfully achieved to form a heterostructure. • Construction of hybrid supercapacitors Ni 1 Co 2 S//AG HSC has better rate performance. 

Facile synthesis and incomplete sulfidation of nickel-cobalt-aluminum ternary layered hydroxide binder-free electrode with enhanced supercapacitor properties

Oxygen evolution reaction (OER), as an essential process in water decomposition and air batteries, has received increasing attention in the context of clean energy production and efficient energy storage. With...

Manganese-based oxides Electrocatalysts for the Oxygen Evolution Reaction: A Review

Developing low‐cost and high‐efficiency catalysts for sustainable hydrogen production through electrocatalytic hydrogen evolution reaction (HER) is crucial yet remains challenging. Here, a strategy is proposed to fill Ni‐vacancy (Niv) sites of dual‐deficient NiO (D‐NiO‐Pt) deliberately created by Ar plasma with homogeneously distributed Pt atoms driven by oxygen vacancies (Ov). The incorporated Pt atoms filling the Niv reduce the formation energy to increase crystal stability, and subsequently combine with additional Ov to tune the electronic structure of the surrounding Ni sites. Thus, a more ideal hydrogen adsorption free energy (ΔGH*) closer to 0 of Ni sites and Pt sites can be achieved. As a result, the D‐NiO‐Pt electrode achieves superior mass activity of ≈1600 mA mg−1 (normalized by platinum) and nearly negligible loss of activity during long‐term operation, which is much better than as‐prepared Pt‐containing NiO catalysts without plasma treatment. A low overpotential of 20 mV is required for the D‐NiO‐Pt at 10 mA cm−2 in alkaline HER, outperforming that of the commercial Pt/C. In addition, the universal access to the other Ni‐based compounds including nickel phosphide (Ni2P), nickel sulfide (Ni0.96S), and nickel selenide (NiSe2) is also demonstrated by employing a vacancy‐driven Pt filling mechanism.

Atomic‐Level Platinum Filling into Ni‐Vacancies of Dual‐Deficient NiO for Boosting Electrocatalytic Hydrogen Evolution

Corrosion behavior of stainless steel-tungsten carbide joints brazed with AgCuX (X = In, Ti) alloys

https://www.researchsquare.com/article/rs-703481/v1.pdf?c=1631900900000

Baishen Liu

Papers

Atomic‐Level Platinum Filling into Ni‐Vacancies of Dual‐Deficient NiO for Boosting Electrocatalytic Hydrogen Evolution

Corrosion behavior of stainless steel-tungsten carbide joints brazed with AgCuX (X = In, Ti) alloys

Realizing the air brazing of ZrO2 ceramics through Al metal