One-step integration of amorphous RuBx and crystalline Ru nanoparticles into B/N-doped porous carbon polyhedra for robust electrocatalytic activity towards the HER in both acidic and basic media

Abstract

As a research hotspot in hydrogen production by water electrolysis, exploring efficient, stable and low-cost hydrogen evolution catalysts is highly desirable and significant for the development of large-scale water electrolysis, but still remains a great challenge, especially under both alkaline and acidic conditions. Herein, amorphous RuB_x and crystalline Ru nanoparticles are successfully integrated into B/N-doped porous carbon polyhedra derived from ZIF-8 via a facile one-step thermal-reduction method, and the obtained composite catalyst (RuB_x-Ru@BNPCH) exhibits admirable catalytic activity and satisfactory stability for the hydrogen evolution reaction in both alkaline and acidic media. In an alkaline medium, RuB_x-Ru@BNPCH can reach a current density of 10, 50 and 100 mA cm⁻² at an ultralow overpotential of 5, 31 and 53 mV, respectively, which is much lower than that of the commercial Pt/C catalyst and most reported hydrogen evolution catalysts. More importantly, a large current density of 300 mA cm⁻² can be obtained on RuB_x-Ru@BNPCH at an extremely low overpotential of 114 mV, which is very significant for the industrial implementation of water electrolysis. Besides, in an acidic medium (0.5 M H₂SO₄), RuB_x-Ru@BNPCH also demonstrates Pt-like activity (an overpotential of 33 mV at 10 mA cm⁻²) and good stability. This work has explored a facile route for constructing amorphous/crystalline catalysts toward highly efficient electrocatalysis, which could be applicable to a wide range of catalytic processes.