Pt single atoms in oxygen vacancies boost reverse water-gas shift reaction by enhancing hydrogen spillover

Abstract

The construction of synergistic catalysis of single atom catalysts (SACs) and oxygen vacancies (O_V) on supports is crucial for the enhancement of heterogeneous catalytic efficiency, yet presents considerable challenges. Herein, we have developed an amine-molecule-assisted in-situ anchoring strategy that effectively stabilizes Pt SACs on O_V sites of reduced TiO₂ (TiO_2−x) by controlling the interaction of amine with Pt species and TiO_2−x. Direct evidence indicates that Pt SACs are anchored on the O_V with forming Pt^δ+–O_V–Ti³⁺ sites and strong metal-support interaction, which not only prevents the sintering of Pt SACs under high-temperature reduction treatments, but also enhances the hydrogen spillover process to facilitate the formation of more O_V sites. During the reverse water-gas shift (RWGS) reaction, the enhanced amount of O_V sites can increase CO₂ adsorption, while the Pt SACs can efficiently promote the activation and spillover of hydrogen. Their combined synergistic effects greatly improve its catalytic performance with a high turnover frequency (TOF) of 9289 h⁻¹ at 330°C and notable stability for over 200 h, surpassing those of Pt clusters and nanoparticles on TiO_2−x. This work provides a new avenue for the controllable synthesis of synergistic catalysts with SACs and O_V, significantly advancing catalytic efficiency.