Controlled transfer-reduction of functional groups with ethanol by their interaction strength with the oxygen vacancies

Controlled reduction of functional groups remains a significant challenge in catalytic chemistry. In this study, we report a novel method for selectively reducing various functional groups using biomass-derived ethanol, mediated by oxygen vacancies in highly dispersed molybdenum oxide on nitrogen-doped carbon. Selectivity for the reduction of four representative substrates, sulfoxides, pyridine N-oxides, nitro compounds, and alkynes is successfully controlled via temperature, yielding the corresponding sulfides, pyridines, amines, and alkenes with high yields. Mechanistic studies indicate that the reactivity of these substrates is directly correlated with their interaction strength with Ov in molybdenum oxides, which effectively adsorb and activate both ethanol and the substrates via Columb interactions and facilitates hydrogen-atom transfer from ethanol to these functional groups. DFT calculations further confirm that Ov in Mo/CN-600 significantly lowers the energy barriers for the H transfer from α-Csp3-H in ethanol to substrates (0.76 eV vs. 2.04 eV), thereby enhancing reactivity. This strategy provides a green and sustainable approach to the controlled reduction of functional groups with strong practical potential. Selectively reducing functional groups without affecting others remains difficult in catalysis. Here, reduction of several groups using ethanol over oxygen-vacancy in molybdenum oxide on nitrogen-doped carbon, with temperature tuning selectivity via hydrogen transfer.