Electrochemistry-Accelerated Water-Gas Shift Reaction on IrN4-RhN4 Dual Sites Catalysts for Efficient Hydrogen Production.

Abstract

The water-gas shift reaction (WGSR) is crucial to the hydrogen economy, which is hampered by the harsh conditions and complicated purification process. In this work, the spatially separated efficient CO conversion and high-purity H₂ production are realized by electrochemistry-accelerated water-gas shift reaction (WGSR) with IrN₄-RhN₄ dual sites single atom catalysts (IrRh-NC) in high-temperature polymer-electrolyte-membrane electrolyzer. In this reaction, the Ir single atoms in the catalysts can rapidly dissociate H₂O at an extremely low potential to supply abundant *OH, which ensures the *OH groups bind to the spontaneously adsorbed *CO on neighboring Rh sites to further accelerate CO conversion. What's more, the elevated temperatures (120-300 °C) maintain water in the gaseous state during the reaction, thus greatly facilitating mass transfer of the reactants CO and H₂O within the reactor. Employing IrRh-NC as the anodic catalyst, the electrolyzer achieves superior CO catalytic performance (424 mA cm^-2 at 0.4 V) and high purity (99.9%) H₂ production (3.2 ml min^-1), surpassing the performance of particle catalysts. This work illuminates the tantalizing possibility for sustainable hydrogen economic development.