Strong photo-thermal coupling effect boosts CO2 reduction into CH4 in a concentrated solar reactor

This study is dedicated to solving the problems of low energy utilization and low yield in the conventional photocatalytic CO2 reduction process. Herein, we constructed a novel concentrated solar (light) reactor and enabled the titanium foam-based monolithic photocatalyst TF@TNT/0.4CoO(x-)0.1CuO to improve the solar en-ergy utilization efficiency and CO2 conversion rate by concentrating light and its thermal effect. We found that the yield of CH4 increased up to 220 times (from 0.53 mu mol/cm(2) to 116.4 mu mol/cm(2)) when the light intensity of the reactor was increased from 400 mW/cm(2) to 4266 mW/cm(2) (10.6 times). Meanwhile, the solar-to-fuel con-version efficiency was improved up to 0.35% in the concentrated solar (light) reactor. We further investigated the origin of the photothermal coupling effect with concentrated light through the electrochemical and photo-chemical measurements. It shows that the concentrated light can further lower the reaction barrier (from 41.62 to 31.51 kJ/mol) and the induced photothermal coupling effect could significantly increase the yield. This provides a valuable strategy for the efficient and environmentally friendly utilization of CO2 using solar energy.

Automated summary

This study aims to address the issues of low energy utilization and low yield in the conventional photocatalytic CO2 reduction process. A novel concentrated solar (light) reactor was constructed, and a titanium foam-based monolithic photocatalyst was developed to improve the solar energy utilization efficiency and CO2 conversion rate. The research findings showed that the CH4 yield increased by 220 times and the solar-to-fuel conversion efficiency improved up to 0.35% in the concentrated solar (light) reactor. The study also explored the origin of the photothermal coupling effect and its impact on the yield increase. This research provides valuable insights for the efficient and environmentally friendly utilization of CO2 using solar energy.