The water–gas shift (WGS) reaction is pivotal for H2 production and purification, yet conventional processes rely on coupled middle and high temperature stages (180–300 °C). Development of wide-temperature-window catalysts could avoid temperature switching and reduce the energy demand. However, room-temperature WGS is particularly limited by sluggish water splitting. Here, we report a continuous-flow solution plasma (CSP) strategy to construct an oxygen vacancy-rich Au1/CeO2–Fe single-atom catalyst (SAC). Fe is uniformly doped into the CeO2 lattice to increase the density of oxygen vacancies and Au is stabilized as isolated atomic sites on the CeO2 surface. By photothermal excitation, the catalyst delivers high WGS activity across 25–300 °C. Notably, at 25 °C, the CO conversion rises from near-zero for conventional catalysts to 35%, overcoming the kinetic barrier of room-temperature WGS for a low CO conversion rate. Mechanistic studies reveal that Fe doping selectively promotes H2O dissociation, and Au SACs enhance CO adsorption and oxidation. Meanwhile, light activates CeO2 lattice oxygen and engages a Mars-van Krevelen cycle. The as-developed catalyst maintains significant activity from ambient temperature to 300 °C without temperature switching, providing a process toward energy-efficient H2 production and purification.
Yu et al. (Mon,) studied this question.