Ruthenium co-anchored by nitrogen and oxygen on lignin derived carbon for high-efficient hydrogen evolution

Abstract

Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is crucial to hydrogen production by water electrolysis. Ruthenium (Ru) supported on nitrogenated carbon catalysts as well as the active sites on them have been widely investigated in HER. Nevertheless, the loading of Ru is still high and some oxygen species usually exist in the nitrogenated carbon and their roles are seldom discussed. Herein, we report a novel HER catalyst of 2 wt% Ru/CNO that Ru clusters uniformly dispersed on O-rich nitrogenated carbon (O-rich CN) synthesized from renewable lignin and low-cost melamine. In 1.0 M aqueous KOH, it presents low overpotential of 13 mV at 10 mA cm−2, comparing to that of 39 mV on a commercial 20 wt% Pt/C catalyst. In particular, it also exhibits low value of 659 mV and excellent stability at a large current density of 2000 mA cm−2. The combination of various spectroscopic experiments and density functional theory calculations reveals that Ru cluster co-anchored by nitrogen and oxygen is the active site. This study unveils the crucial role of O in nitrogenated carbon to HER and demonstrates a lignin derived carbon as an excellent electrocatalyst support, supplying a strategy for developing high-efficient HER catalysts.