Gas-Phase Cation Exchange toward Porous Single-Crystal CoO Nanorods for Catalytic Hydrogen Production

As a promising catalyst for hydrogen evolution, cobaltous oxide (CoO) with good crystallinity and large surface is highly anticipated to enhance the catalytic performance. Here we present a facile route for the fabrication of porous single-crystal (PS) CoO nanorods (NRs) by gas phase cation exchange of ZnO NRs. The single-crystal structure of ZnO template is well-preserved after the cation exchange, and numerous nanopores form in the PS CoO NRs because of the volume shrinkage. As-synthesized PS CoO NRs exhibit outstanding catalytic activities for NaBH4 hydrolysis in alkaline solutions, outperforming polycrystalline CoO NRs and even noble metal catalysts.