No abstract

Electrocatalysis is a potential method for sustainable hydrogen production, and the development of non-noble metal-based effective electrocatalysts for electrochemical water splitting is the core of exploiting and utilizing renewable energy. Herein, a stupendous electrocatalyst with multiheterostructure interfaces and 3D porous structure is synthesized, and the mechanisms of enhanced electrocatalytic activity combining multicharacterizations and density functional calculations are clarified. Especially, the fabricated Co 2 P/N@Ti 3 C 2 T x @NF (denoted as CPN@TC) exhibits an ultralow overpotential of 15 mV to arrive at a current density of 10 mA cm −2 with the long-term durability and a small Tafel slope of 30 mV dec −1 in 1 m KOH, which even compares with noble metal catalysts favorably. The outstanding HER activity is ascribed to multiheterointerfaces for adsorbing H 2 O and H*, fine conductivity for the electronic transmission, and well-designed structure for rapid transport of ions and gases. It is reasonable to think that the synthetic strategy of CPN@TC can be extended to the preparation of transition-metal-based phosphides for enhanced catalytic performance.

Preparation of high-activity and earth-abundant bifunctional catalysts for efficient electrochemical water splitting are crucial and challenging. Herein, Co-doped Ni 3 N nanosheets loaded on nickel foam (Co−Ni 3 N) were synthesized. The as-prepared Co−Ni 3 N exhibits excellent catalytic activity toward both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in alkaline media. Density functional theory (DFT) calculation reveals that Co−Ni 3 N with redistribution of electrons not only can facilitate the HER kinetics but also can regulate intermediates adsorption energies for OER. Specifically, the Co−Ni 3 N exhibits high efficiency and stable catalytic activity, with an overpotential of only 30 and 270 mV at a current density of 10 mA cm −2 for the HER and OER in 1 M KOH, respectively. This work provides strong evidence to the merit of Co doping to improve the innate electrochemical performance in bifunctional catalysts, which might have a common impact in many similar metal− metal nitride electrocatalysts.

In this study, effectively conductive rGO (reduced graphene oxide) was used as the supporter both to promote charge transfer and to refine particle size of WC, to realize efficient and stable HER performance.