Tuning hydrogen binding modes within RuO2 lattice by proton and electron co-doping for active and stable acidic oxygen evolution

The bigger pictureGreen hydrogen production by a solid polymer electrolyzer (SPE) using pure water as electrolyte is a very competitive solution for storing renewable electricity, yet such technology is seriously restricted by the lack of a durable and active electrocatalyst for a proton-rich anode owing to high catalyst dissolution under polarization potential. A pivotal issue remaining to be addressed is how to simultaneously improve the activity and suppress the formation of lattice oxygen vacancy. Here, a simple proton and electron co-doping method was employed to tune hydrogen binding modes within RuO2 lattice, which not only increased electrocatalytic activity but also stabilized lattice oxygen. This work not only provides new insight into electrocatalyst design for acidic oxygen evolution reaction but also demonstrates the durable operation of SPE under industrial current density.Highlights•Proton and electron co-doping was proposed to construct Ru-O-H bond•Tuning the hydrogen binding modes benefit the activity and stability of H-RuO2•The required overpotential was only 200 mV @ 10 mA cm−2 in a three-electrode cell•The assembled SPE device could stably operate at 0.5 A cm−2SummarySolid polymer electrolyzer (SPE), which directly uses pure water as electrolyte, holds great promise for green hydrogen production, yet developing a durable and active electrocatalyst for a proton-rich anode remains a bottleneck issue owing to the high catalyst dissolution under polarization potential. Here, proton and electron co-doping was employed to construct an Ru-O-H···O bond within RuO2 lattice, and the hydrogen binding modes not only engineered the electronic interaction between Ru and O atoms but also formed a hydrogen bond, which was demonstrated to be an effective way to increase the electrocatalytic activity and stabilize the lattice oxygen. The intrinsic activity of representative 75-H-RuO2 loaded on a glassy carbon electrode was almost ten times that of the pristine one, only requiring an overpotential of 200 mV (@10 mA cm−2). Moreover, it demonstrated ideal stability (@0.5 A cm−2) in the SPE device.Graphical abstract