Boron/nitrogen-trapping and regulative electronic states around Ru nanoparticles towards bifunctional hydrogen production.

ABSTRACT

Developing a straightforward and general strategy to regulate the surface microenvironment of a carbon matrix enriched with N/B motifs for efficient atomic utilization and electronic state of metal sites in bifunctional hydrogen production via ammonia-borane hydrolysis (ABH) and water electrolysis is a persistent challenge. Herein, we present a simple, green, and universal approach to fabricate B/N co-doped porous carbons using ammonia-borane (AB) as a triple functional agent, eliminating the need for hazardous and explosive functional agents and complicated procedures. The pyrolysis of AB induces the regulation of the surface microenvironment of the carbon matrix, leading to the formation of abundant surface functional groups, defects, and pore structures. This regulation enhances the efficiency of atom utilization and the electronic state of the active component, resulting in improved bifunctional hydrogen evolution. Among the catalysts, B/N co-doped vulcan carbon (Ru/BNC) with 2.1 wt% Ru loading demonstrates the highest performance in catalytic hydrogen production from ABH, achieving an ultrahigh turnover frequency of 1854 min-1 (depending on the dispersion of Ru). Furthermore, this catalyst shows remarkable electrochemical activity for hydrogen evolution in alkaline water electrolysis with a low overpotential of 31 mV at 10 mA cm-2. The present study provides a simple, green, and universal method to regulate the surface microenvironment of various carbons with B/N modulators, thereby adjusting the atomic utilization and electronic state of active metals for enhanced bifunctional hydrogen evolution.