Escalating Photo-to-thermal Effects for Efficient and Selective Photosynthesis of C2H4 from CO2 and H2O

Dual-layer system design and photothermal catalysis without external heat supply. • Exceptional catalytic performance and selectivity. • Exploring the mechanism of thermally-assisted photocatalysis. The photocatalytic conversion of CO 2 and H 2 O into C 2 H 4 is a promising approach for carbon recycling, yet current systems are limited by inefficient solar energy utilization, which confines C 2 H 4 production to micromolar levels. To address this challenge, photo-thermal catalysis was developed. The Ti 3 C 2 T x MXenes substrate, characterized by broad-spectrum solar absorption and ultralow mid-infrared emissivity, provides efficient photothermal conversion, raising the local reaction temperature and accelerating both molecular diffusion and charge carrier migration, which integration enhances the C-C coupling efficiency, leading to a remarkable 1.35   mmol·g -1 ·h -1 of C 2 H 4 production rate and 75.1% of C 2 H 4 selectivity, which surpasses the current benchmarks for photocatalytic CO 2 -to-C 2 H 4 conversion. Moreover, when deployed in a custom-designed outdoor reactor equipped with a Fresnel lens concentrator and a continuous gas flow system, the catalyst delivered up to 11.3   mL of C 2 H 4 with a total CO 2 single-pass conversion rate of 2.6% after 8   h. These results not only establish a new benchmark for photocatalytic CO 2 -to-C 2 H 4 conversion but also provide valuable insights into the cooperative mechanisms of photochemical and photothermal processes, paving the way for advanced artificial photosynthesis technologies. Download: Download high-res image (253KB) Download: Download full-size image The findings reveal cooperative mechanisms between photothermal and photocatalytic processes, establishing a generalizable design principle for advanced catalysts aimed at improving solar-to-chemical energy conversion and enabling more efficient artificial photosynthesis.