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.