Photothermal CO2 Reduction over Geopolymer/Ag9(SiO4)2NO3 Catalysts Modified by Photoreduced Co2+

A type of photothermal catalyst was prepared by photoreducing cobalt ions with geopolymer/Ag9(SiO4)2NO3 (GA). The loading of Co0 significantly expanded the visible-light response range. Due to the photoreduction effect, the loading of Ag0 and Co0 facilitated the transfer of photogenerated electrons and strong thermal excitation, significantly enhancing the photothermal synergy effect. The photothermal catalyst achieved a CO production rate of 70.20 mmol·gcat−1·h−1, and the selectivity of CO reached 97.67% at 400 °C. The CO product rate in the fifth cycle still reached 68.8 mmol·gcat−1·h−1, which provided a reference for extending the functionality of photocatalysts after the photoreduction of heavy metal ions.