Solar-driven CO₂ reduction to value-added fuels under normal temperature and pressure could help to simultaneously solve the energy issues and environmental problems, whereas the low CO₂ conversion efficiency severely hampers its practical implementation. In response to the challenges, Prof. Yi Xie and Prof. Yongfu Sun from University of Science and Technology of China designed a new catalyst of partially oxidized SnS₂ atomic layers, whose energy band structures were clearly resolved by the synchrotron radiation photoemission spectroscopy and the X-ray absorption near-edge spectroscopy from National Synchrotron Radiation Laboratory (NSRL). Moreover, surface photovoltage spectroscopy, in situ Fourier transform infrared spectroscopy spectra and density functional-theory calculations revealed that locally oxidized domains confined in SnS₂ atomic layers not only benefited for charge-carrier separation kinetics, but also lowered the activation energy barrier through stabilizing the COOH* intermediates, hence realizing efficient visible-light-driven CO₂ reduction. In addition, the synchrotron-based vacuum ultraviolet photoionization mass spectrometry from NSRL demonstrated that the detected CO could undoubtedly be attributed to the photoreduction of CO₂. This work was published in Journal of the American Chemical Society (2017, 139, 18044), opening new avenues toward achieving efficient CO₂ conversion performances.

chematic representation of CO₂ photoreduction mechanism on the mildly oxidized SnS₂ atomic layers.