The active center for the adsorption and activation of carbon dioxide plays a vital role in the conversion and product selectivity of photocatalytic CO₂ reduction. Here, we find multiple metal sulfides CuInSnS₄ octahedral nanocrystal with exposed (1 1 1) plane for the selectively photocatalytic CO₂ reduction to methane. Still, the product is switched to carbon monoxide on the corresponding individual metal sulfides In₂S₃, SnS₂, and Cu₂S. Unlike the common metal or defects as active sites, the non-metal sulfur atom in CuInSnS₄ is revealed to be the adsorption center for responding to the selectivity of CH₄ products. The carbon atom of CO₂ adsorbed on the electron-poor sulfur atom of CuInSnS₄ is favorable for stabilizing the intermediates and thus promotes the conversion of CO₂ to CH₄. Both the activity and selectivity of CH₄ products over the pristine CuInSnS₄ nanocrystal can be further improved by the modification of with various co-catalysts to enhance the separation of the photogenerated charge carrier. This work provides a non-metal active site to determine the conversion and selectivity of photocatalytic CO₂ reduction.

二氧化碳吸附和活化的活性中心对于光催化CO ₂还原的转化率和产物选择性起着至关重要的作用。在这里，我们发现具有暴露的(1 1 1)平面的多种金属硫化物CuInSnS _{4八面体纳米晶体，用于选择性光催化CO 2}还原为甲烷。_{尽管如此，产物在相应的单个金属硫化物In 2} S ₃、SnS ₂和Cu ₂ S上转变为一氧化碳。与作为活性位点的常见金属或缺陷不同，CuInSnS ₄中的非金属硫原子被揭示为是响应CH ₄产物选择性的吸附中心。_{CuInSnS 4}的缺电子硫原子上吸附的CO ₂碳原子有利于稳定中间体，从而促进CO ₂转化为CH ₄。通过使用各种助催化剂进行修饰，可以进一步提高CH ₄产物相对于原始CuInSnS ₄纳米晶体的活性和选择性，以增强光生电荷载流子的分离。这项工作提供了一个非金属活性位点来确定光催化CO ₂还原的转化率和选择性。