Construction of glucose precursor carbon/TiO2 heterojunction with high ligand-to-metal charge transfer (LMCT) for visible light driven CO2 reduction
Abdullah Bafaqeer, Nor Aishah Saidina Amin, Muhammad Tahir, Aniz Chennampilly Ummer, Hammam Abdurabu Thabit, Rajesh Theravalappil, Jamilu Usman, Nabeel Ahmad
Abstract
Well-designed fabrication of glucose precursor carbon-doped TiO 2 heterojunction with high Ligand-to-Metal Charge Transfer (LMCT) for enhancing photocatalytic CO 2 conversion has been examined. Photocatalysts were fabricated using a single-step thermal method and tested in a fixed-bed reactor under visible light. The 6 % glucose precursor carbon-doped over TiO 2 (6 %C/TiO 2 ) photocatalyst has demonstrated excellent activity in converting CO 2 to CO and CH 4 under visible light. The main product yield, CO of 739.9 μmol g-cat −1 was produced over 6 %C/TiO 2 , which is 4.4 folds the amount of CO obtained over TiO 2 (168.7 μmol g-cat −1 ). The XPS findings reveal the presence of different surface components containing C-OH, C C, and C O functional groups, which contribute to the formation of a ligand-metal-charge-transfer (LMCT) complex between carbon and TiO 2 photocatalyst. Carbon-doped TiO 2 possesses a narrow energy band and the ability to effectively absorb solar light, which enables efficient transportation of electrons generated by photon excitation. The mechanism of the carbon-doped TiO 2 in CO 2 conversion to CO and CH 4 is postulated to be consistent with the LMCT complex phenomena. Therefore, carbon-doped TiO 2 provides heterojunction for localization of electrons, impedes the rate at which charges recombine, and reduces the band gap energy, leading to improved photocatalytic performance when exposed to visible light.