Localized formation of TiOx-tailored Pt nanoclusters on Al2O3 via a solid-state mixing approach for efficient and robust LOHC dehydrogenation

Abstract

Strong metal-support interaction (SMSI) has played versatile roles in determining the catalytic performance of supported metal species. In TiO2-based catalysts, the SMSI effect, particularly involving TiOx coverage, is highly sensitive to the synthesis methodology and thermal treatment. In this study, we present a strategy of solid-state mixing via solvent-deficient precipitation to integrate a reducible anatase-TiO2 (a-TiO2) with Pt nanoclusters and a non-reducible Al2O3 support. This approach affords a mesoporous Pt–Al2O3–TiO2 catalyst (mPtAT) with heterogeneously structured interfaces, where Pt nanoclusters adjacent to TiO2 are covered by TiOx up to approximately half of their height from the Pt–TiO2 interface. This coverage induces more partially oxidized Pt species while suppressing under-coordinated Pt sites. These structural characteristics enable mPtAT to exhibit profound catalytic activity, enhanced product selectivity and long-term stability for hydrogen release from liquid organic hydrogen carriers (LOHC). Moreover, the SMSI effects noticed in mPtAT are confirmed by varying the H2 reduction temperature and a-TiO2 content. Consequently, the solid-state mixing strategy can derive the localized generation of TiOx-tailored Pt nanoclusters near the TiO2 surface of mPtAT, demonstrating the catalytic outperformance in efficiency and stability of LOHC dehydrogenation reactions.