Cobalt‐Sputtered Anodic Aluminum Oxide Membrane for Efficient Photothermal CO₂ Hydrogenation

Abstract The rational design of nanoarray‐structured catalysts is an accessible way to increase light absorption ability and boost photothermal CO₂ conversion efficiency. However, practical application of current nanoarrays is hindered by complex synthesis procedures, high costs, and low catalyst yields. Herein, we report a simple, robust method to prepare efficient photothermal catalyst by sputtering Co nanoparticles on commercial anodic aluminum oxide (AAO) membrane. The detailed study shows that gas diffusion and catalytic activity can be affected by AAO structures, such as channel size and shape. The optimized Co@dpAAO catalyst reached a record Co‐based photothermal CO₂ conversion rate of 1666 mmol ⋅ g_Co⁻¹ ⋅ h⁻¹. This study not only provides a facile way to synthesize efficient catalysts, but also promotes the understanding of constructing nanoarray‐based photothermal catalysts.