Ultrafine Ru nanoparticles anchored on B, N co-doped hollow carbon microspheres for boosted hydrogen evolution reaction.

Abstract

Developing efficient and durable non‑platinum electrocatalysts for alkaline hydrogen evolution reaction (HER) is critically important for sustainable water electrolysis. In this work, we report the synthesis of novel Ru nanoparticles-anchored N, B co-doped hollow carbon microspheres (Ru/N,B-HCMSs) and their application in electrocatalyzing the alkaline HER. The catalyst displays an overpotential of only 32 mV at 10 mA cm-2, with 5.8-fold higher mass activity relative to commercial Pt/C, and hardly any loss in catalytic activity after 150 h continuous operation at a current density of 100 mA cm-2. Density functional theory calculations suggest that B doping alters the electronic states of Ru active sites. This doping effect downshifts the d-band center for favorable hydrogen adsorption free energy (ΔGH*), cuts the water dissociation barrier from 1.01 to 0.46 eV, and speeds up electron transfer from Ru toward the carbon support. These combined effects boost HER kinetics and deliver excellent activity as well as durability. This work provides useful insights for designing high performance Ru based electrocatalysts.