Semimetal bismuth mediated UV-vis-IR driven photo-thermocatalysis of Bi4O5I2 for carbon dioxide to chemical energy

Semimetal bismuth has attracted extensive interests, which were ascribed to the photo-thermal effect and co-catalyst properties. In this paper, Bi/Bi4O5I2 composites were synthesized through a molecular precursor hydrolytic process, and the sunlight induced semimetal Bi mediated photo-thermocatalysis of Bi4O5I2 for carbon dioxide to chemical energy was studied. When the optimal mole ratio of Bi: I was selected at 1.95: 1, Bi/Bi4O5I2 displayed outstanding photo-thermocatalytic carbon dioxide to chemical energy (CO and CH4). Under simulate sunlight (UV-vis-IR) irradiation, the CO and CH4 generation over Bi/Bi4O5I2 enhanced to 40.02 mu mol h(-1) g(-1), and 7.19 mu mol h(-1) g(-1), respectively. The light to chemical energy (LTCE) conversion efficiency (80.2 x10(-6)) was about 6.47 times than Bi4O5I2 (12.4 x10(-6)), and 68.55 times than Bi4O5I2 without IR irradiation (1.17 x10(-6)). The dramatically enhanced photo-thermocatalysis activity of Bi/Bi4O5I2 can be attributed to the co-catalyst and photo-thermal effect of Bi nanoparticles, which prohibiting the electron-hole recombination and accelerating light to thermal energy conversion, respectively. Furthermore, the enhanced photo-induced carrier separation rate and reaction system temperature of Bi/Bi4O5I2 was testified.