Heteroatom doping enables hydrogen spillover via H/e diffusion pathways on a non-reducible metal oxide.

Hydrogen spillover, the simultaneous diffusion of protons (H) and electrons (e) is considered to be applicable to ubiquitous technologies related to hydrogen but limited to over reducible metal oxides. The present work demonstrates that a non-reducible MgO with heteroatom Al dopants (Al-MgO) allows hydrogen spillover in the same way as reducible metal oxides. Furthermore, a H storage capacity of this material owing to hydrogen spillover is more than three times greater than those of various standard metal oxides based on H transport channels within its bulk region. Atomic hydrogen diffuses over the non-reducible Al-MgO produces active H-e pairs, as also occurs on reducible metal oxides, to enhance the catalytic performance of Ni during CO hydrogenation. The H and e diffusion pathways generated by the heteroatom Al doping are disentangled based on systematic characterizations and calculations. This work provides a new strategy for designing functional materials intended to hydrogen spillover for diverse applications in a future hydrogen-based society.