Structure–function evolution of transition metal molybdate catalysts driven by hydrodeoxygenation environment

Abstract

Bulk mixed metal oxides are increasingly explored as sustainable catalysts, yet their behaviour under hydrodeoxygenation (HDO) environments remains poorly understood. Here, we reveal how first-row transition metal molybdates (MMo, M = Mn, Fe, Co, Cu, Zn) undergo metal-dependent restructuring under acetone HDO, leading to the emergence of functional Mo-rich phases with distinct redox and catalytic properties. Catalytic testing combined with comprehensive post-reaction characterization shows that HDO conditions promote the formation of substoichiometric molybdenum species (MoO_xC_y) whose abundance and distribution are governed by the reducibility of the incorporated metal. These dynamically generated phases promote efficient deoxygenation through multiple pathways and explain the broad reactivity trends across the MMo series. Our findings demonstrate that hydrodeoxygenation can direct the self-assembly of transition metal molybdates into catalytically versatile architectures, providing generalizable principles for designing redox-active oxide catalysts for biomass valorization and other oxygen-rich feedstocks.