100% Conversion of CO-CH with Non-Precious Co@ZnO Catalyst in Hot Water.

The combination of solar energy and natural hydrothermal systems will innovate the chemistry of CO hydrogenation; however, the approach remains challenging due to the lack of robust and cost-effective catalytic system. Here, Zn which can be recycled with solar energy-induced approach was chosen as the reductant and Co as catalyst to achieve robust hydrothermal CO methanation. Nanosheets of honeycomb ZnO were grown in situ on the Co surface, resulting in a new motif (Co@ZnO catalyst) that inhibits Co deactivation through ZnO-assisted CoO reduction. The stabilized Co and interaction between Co and ZnO functioned collaboratively toward the full conversion of CO-CH. In situ hydrothermal infrared spectroscopy confirmed the formation of formic acid as an intermediate, thereby avoiding CO formation and unwanted side reaction pathways. This study presents a straightforward one-step process for both highly efficient CO conversion and catalyst synthesis, paving the way for solar-driven CO methanation.