Continuously Selective Photocatalytic CO<sub>2</sub> Fixation via Controllable S/Se Ratio in a TiO<sub>2</sub>–MoS<sub><i>x</i></sub>Se<sub><i>y</i></sub> Dual-Excitation Heterostructured Nanotree
Deng Long, Jia Liu, Lin Bai, Longfei Yan, Huanhuan Liu, Zhijun Feng, Lingling Zheng, Xinyi Chen, Shuang Li, Miao Lü
Abstract
Photocatalytic CO2 fixation is widely considered as a promising approach for recycling carbon-based energy resources. However, it is still beyond practical application due to the low efficiency and poor selectivity. Therefore, a TiO2–MoSxSey heterostructured nanotree has been designed for product-oriented optimization of photocarrier transport during the photocatalytic CO2 fixation. The controllable S/Se ratio in MoSxSey can tweak the band edge, that is, the active energy level for CO2 fixation, achieving a tunable C1 and C2 production. TiO2 and MoSxSey synergizes under a dual-excitation mechanism to favor the separation and transports of the photocarriers. Prominently, a CH3CH2OH generation rate of 704.38 μmol g–1 h–1 has been archived with S/Se < 1, while another C1 product of HCOOH and a C2 product of CH3COOH can be gradually obtained with S/Se > 1.