Pt Nanoparticles Supported on Hydroxylated TiO2 as Catalysts for the Reverse Water Gas Shift Reaction

The reverse water gas shift (RWGS) reaction is deemed as a potent modality for the valorization of CO<INF>2</INF>, which widely utilizes supported catalysts owing to their high availability of active sites. However, active metal particles on supported catalyst surfaces tend to undergo sintering under high temperatures, leading to severe deactivation. Therefore, selecting a support with strong adhesion to prevent the aggregation of metal nanoparticles represents a significant challenge in constructing high-temperature durable catalysts for the RWGS reaction. In this study, we used the hydroxylated TiO<INF>2</INF> as support to anchor highly dispersed Pt nanoparticles and prepared the excellent xPt/TiO<INF>2</INF> catalyst for the RWGS reaction. Notably, the 0.5Pt/TiO<INF>2</INF> catalyst exhibited superior activity (120.1 x 10-5 mol<INF>CO<INF>2</INF></INF><middle dot>g<INF>cat</INF>-1<middle dot>s-1 at 600 degrees C), surpassing most Pt-based catalysts, and exceptional stability (<6.7% CO<INF>2</INF> conversion loss over 200 h), outperforming the 0.5Pt/TiO<INF>2</INF>-ref catalyst (7.9% loss in 80 h). Systematic characterizations illustrated that Pt nanoparticles could be effectively anchored by hydroxylating the TiO<INF>2</INF> support, and the constructed 0.5Pt/TiO<INF>2</INF> catalyst maintained similar to 2 nm Pt nanoparticles within 80 h even under harsh reaction conditions. Besides, the existence of abundant oxygen vacancies, coupled with the higher electron density of Pt, enhanced the ability for CO<INF>2</INF> adsorption and H<INF>2</INF> activation, synergistically facilitating the RWGS reaction. This strategy of constructing hydroxylated supports to stabilize Pt nanoparticles furnishes insights into the design and development of supported catalysts.