Natural halloysite nanotubes supported Ru as highly active catalyst for photothermal catalytic CO₂ reduction

Photothermal catalytic CO₂ reduction has emerged as a promising approach to efficiently utilize solar energy and reduce greenhouse gas emissions. Designing novel catalyst with high activity and selectivity is essential and challenging for practical applications of photothermal CO₂ reduction. Herein, we report that natural halloysite nanotubes-supported Ru nanoparticles can boost the photothermal catalytic activity and selectivity of CO₂ methanation under continuous flow conditions. The photothermal catalytic performance of optimized catalyst is up to 1704 mmolCH₄ g_cat⁻¹ h⁻¹ with 93% CH₄ selectivity and 68% CO₂ conversion, outperforming any other Ru-based catalysts in photothermal CO₂ reduction. Mechanistic studies show that the outstanding catalytic performance is mainly attributed to the unique mesoporous tubular structure, excellent ability of light-to-heat and interfacial interactions between the halloysite nanotubes and Ru. This method of utilizing natural minerals as support provides a facile avenue for rational design of abundant and low-cost catalysts for efficient photothermal catalytic CO₂ reduction.