Metal-free borocarbonitrides as electrocatalysts for the hydrogen evolution reaction under alkaline media

This study presents the successful production of metal-free borocarbonitrides (BCN) based on graphene as carbon sources, and its application for hydrogen evolution reaction (HER) in alkaline medium (1 M KOH) via one-step pyrolysis. Synthesis parameters such as the temperature and calcination time were optimized in order to improve the electrocatalytic activity being 10 h and 900 °C the optimal conditions of calcination. These conditions generated a low oxygen content and a stable graphene-like structure doped with B and N. In-depth XPS analysis revealed the strong N-B bond formed during the calcination, allowing the creation of a stable and homogeneous B[sbnd]C[sbnd]N ternary material. The ratio of B:N were optimized obtaining for a ratio 0.5:40 the most active catalyst. This catalyst reached an overpotential at 10 mA cm−2 of 295 mV in 1 M KOH after an activation under Linnear Sweep Voltammetry (LSV) and chronopotentiometry, which is close to that observed for a commercial 20 % Pt/C catalyst. © 2024 Elsevier B.V.