Sea-Urchin-like Hollow CuMoO₄–CoMoO₄ Hybrid Microspheres, a Noble-Metal-like Robust Catalyst for the Fast Hydrogen Production from Ammonia Borane

Hollow micro-/nanostructures are an extremely important type of materials with many applications in different areas. In this work, we have prepared sea-urchin-like hollow CuMoO₄–CoMoO₄ hybrid microspheres with numerous nanorods on the surface by a template-free approach. The possible formation mechanism for the hollow microstructures is proposed based on the experimental results. As catalysts in hydrolyzing ammonia borane (AB) for H₂ production, the hollow CuMoO₄–CoMoO₄ hybrid microspheres exhibit ultrahigh catalytic performance with a turnover frequency of 104.7 mol_hydrogen min^–1 mol^–1_cat, which is one of the most active noble-metal-free catalysts in the literature. The activity of the hollow microspheres is even higher than that of many noble-metal based catalysts. A remarkable synergistic effect is experimentally confirmed between CoMoO₄ and CuMoO₄. The theoretical calculations demonstrate that the energy barrier in the rate-determining step of AB hydrolysis will significantly decrease in the presence of hybrid catalysts. These findings provide new insight into design of cheap hybrid catalysts with high performance toward AB hydrolysis.