Hydrogenolysis cleavage of Csp2-Csp3 bond over a metal-free NbOPO4 catalyst

Ru/NbOx catalysts, which combine the merits of facile hydrogen activation, strong binding to benzene ring and the presence of Brønsted acid sites, were well investigated toward Csp2-Csp3 bond cleavage. Herein, we unlock the ability of bare NbOx catalyst in the dissociation and activation of hydrogen molecule and further hydrogenolysis of the Csp2-Csp3 model compounds including polystyrene (PS). In-situ Drift and density functional theory (DFT) calculations reveal that H2 can be dissociated and surface hydride species can be produced over Nb2O5 through heterolytic and homolytic cleavages of H2. We also find that the existence of surface oxygen vacancies plays a key role in stabilizing hydride species. Further, the NbOPO4 catalyst not only allows the conversion of phenylcyclohexane to monocyclic compounds by cleaving Csp2-Csp3 bond, but also enables the conversion of PS to arenes with a high selectivity. This study provides and proves for the first time, the unique ability of metal oxides (phosphates) in the hydrogenolysis of compounds and plastics containing Csp2-Csp3 bonds.