Integrating trace ruthenium cluster with cobalt boride toward superior overall water splitting in neutral media

Cobalt boride which is an active bifunctional water splitting catalyst in alkaline media shows poor activity in neutral media. We found that trace ruthenium (Ru) cluster deposition (80 μg·cm-2) on cobalt boride by simple wet chemical reduction method can dramatically improve both its hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity in neutral solution. The electron transfer from Co-B to Ru may result in the easier water dissociation step so as to facilitate the catalytic process. The resulting Ru@Co-B/Ni binder-free electrode could supply 10 mA cm-2 at overpotentials of 56 mV for HER and 280 mV for OER in 0.5 M phosphate buffer electrolyte. This work proposed a fruitful approach to advance the water splitting performance of transition metal boride in neutral media.