Oxygen vacancy excites Co3O4 nanocrystals embedded into carbon nitride for accelerated hydrogen generation

Highly active and robust non-noble metal catalysts are the key to large-scale application of hydrogen energy. In this article, abundant oxygen vacancies are injected into Co3O4 nanocrystals by controlling oxidation. These Co3O4 nanocrystals with oxygen vacancies are embedded into carbon nitride sheets. In the hydrolysis of ammonia borane, oxygen vacancies boost Co3O4 nanocrystalline catalyst to exhibit an outstanding catalytic activity. The hydrogen generation rate reaches up to 11,410 mL min−1 gCo−1 (313 K) owing to the presence of oxygen vacancies in Co3O4. In the stability tests, Co-CN-O-100 still maintains excellent catalytic activity with a specific rate of 9070 mL min−1 gCo−1 (80 %) after five cycles. The carbon nitride retards the growth of Co3O4 NCs and prevents active components from leaching. An oxygen vacancy-relating catalytic mechanism is proposed for the acceleration of rate-determining step of hydrolysis of ammonia borane according to a density functional theory simulation. This work makes a demonstration for the potential of oxygen vacancies in the development of energy catalysis.