Modulating the Electronic Structure of RuO 2 through Cr Solubilizing for Improved Oxygen Evolution Reaction.

Hydrogen production from water electrolysis is important for the sustainable development of hydrogen energy. Nevertheless, the naturally torpid property of anodic oxygen evolution reaction (OER) kinetics and poor stability of its catalysts significantly restrict the development of electrochemical water splitting. Here, a Ru 0.6 Cr 0.4 O 2 electrocatalyst is synthesized, which reveals excellent OER activity with the overpotential of only 195 mV at 10 mA cm -2 and excellent stability with the potential increase of merely 5.3 mV after 20 h continuous OER test in acidic media. Theoretical calculations reveal that the solubilizing of Cr into RuO 2 could adjust the electron distribution, making the d-band center of Ru far away from the Fermi level. This behavior reduces the binding energy with Ru and O and accelerates the rate-determining step of OER (i.e., the formation of *OOH), thereby increasing OER activity. In addition, the incorporation of Cr increases the energy of oxygen defect formation and reduces the participation of lattice oxygen, thus improving the stability of the catalyst. This research furnishes a feasible policy for the development of highly active and stable catalysts in acidic media by regulating the electronic structure of RuO 2 .