Conversion of CO₂ into useful fuels and chemicals through solar energy offers opportunities to address the crisis of energy for fossil fuels and reduce climate-changing CO₂ emissions. In order to make use of solar energy efficiently, fabrication of photocatalysts that can work under longer wavelengths (such as λ > 600 nm), remains to attract intense attention. Herein, the NiO nanosheets containing an abundant of Ni&O vacancies were fabricated. Through fine-tuning the density of vacancies, we are able to control the selectivity of CH₄, CO, and H₂ of the photoreduction CO₂ reaction. Furthermore, under irradiation with λ > 600 nm, the H₂ evolution reaction can be completely suppressed. The DFT+U calculations revealed that under the irradiation wavelength above 600 nm, the photogenerated electrons located on the defect state of NiO could only overcome the Gibbs free energy barrier of CO₂ reduction to CH₄ and CO, rather than that for H₂ evolution.

通过太阳能将CO ₂转化为有用的燃料和化学品，为解决化石燃料的能源危机和减少气候变化的CO ₂排放提供了机会。为了有效地利用太阳能，可以在更长波长（例如λ > 600 nm）下工作的光催化剂的制造仍然引起人们的极大关注。在此，制备了包含大量Ni＆O空位的NiO纳米片。通过微调空位密度，我们能够控制光还原CO ₂反应中CH ₄，CO和H ₂的选择性。此外，在λ > 600 nm的照射下，H ₂进化反应可以被完全抑制。所述DFT + U的计算表明，照射波长大于600纳米下，位于对NiO的缺陷状态的光生电子只能克服CO的吉布斯自由能屏障₂还原成CH ₄和CO，而不是用于h ₂进化。