Infrared Light-Driven CO2 Overall Splitting at Room Temperature

Liang Liang, Xiaodong Li, Yongfu Sun, Yuanlong Tan, Xingchen Jiao, Huanxin Ju, Zeming Qi, Junfa Zhu, Yi Xie

Index: 10.1016/j.joule.2018.02.019

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Abstract

To date, infrared (IR) light constituting almost 50% of the solar energy has never been utilized, owing to an insurmountable contradiction between IR light utilization and CO2photoreduction. To break through this limitation, we designed an ultrathin intermediate-band semiconductor, and hence first realized IR-driven CO2overall splitting on a single material without using any sacrificial reductants. Taking the synthetic ultrathin cubic-WO3layers as an example, theoretical calculations disclose that the created oxygen vacancies reaching a critical density results in an intermediate band, verified by synchrotron-radiation valence-band spectra, photoluminescence spectra, UV-vis-NIR spectra, and synchrotron-radiation IR reflectance spectra. As a result, the oxygen-deficient WO3atomic layers display IR-driven CO2overall splitting to CO and O2, while their catalytic activity proceeds without deactivation even after 3 days. Also, the higher oxygen vacancy concentration favors CO2adsorption and activation into COOH* radical, affirmed by CO2temperature-programmed desorption spectra andin situFTIR spectra, hence guaranteeing increased CO and O2formation rates.