The hydrogen activation, migration, and hydrogenation on metal-free TiH2(O)

Hydrogen activation and migration of active hydrogen species are of great significance for the hydrogen-involving reaction and have attracted much attention. Herein, we reported an unexpected result that H-2 activation occurred on a TiH2(O) material, which possesses a unique structure with TiH2 in the core and an amorphous TiOxHy surface layer. The TiOxHy surface layer enriched with defects and "TiOO" species account for the intrinsic activity of TiH2(O) for H-2 heterolytic cleavage. As a hydrogen-rich material, TiH2(O) acts as a hydrogen reservoir, favoring not only the spillover of active hydrogen species on the surface layer but also their migration into the bulk phase of TiH2. Without the addition of extra active metals, TiH2(O) exhibited excellent catalytic performance in the hydrogenation of biomass-derived vanillin.