A fundamental challenge in CO₂ photoreduction is to establish highly efficient photocatalysts with efficient charge separation, wide-spectrum absorption and effective CO₂ adsorption. The former two can be achieved by fabricating Z-scheme systems with narrow-bandgap semiconductor, and the last can be realized by creating vacancy defects in the catalyst. Herein, ZnSe/CdSe composites with different ZnSe/CdSe ratios are prepared via epitaxial growth of CdSe on ZnSe nanoparticles, which exhibit much higher CO₂ photoreduction performance than pristine ZnSe under visible-light irradiation. ZnSe/CdSe (precursor ratio Zn:Cd = 1:0.125) exhibits an optimal CO yield (116.9 μmol g^-1), which is 33.4 times that of pristine ZnSe (3.5 μmol g^-1). Electron spin resonance (ESR) and density functional theory (DFT) calculations reveal that charge transfer at the ZnSe/CdSe interface follows Z-scheme pathway. Improved light harvesting by loading CdSe can further promote charge generation. Se vacancy generated during the preparation can facilitate CO₂ adsorption.

CO _2光还原的根本挑战是建立具有有效电荷分离，广谱吸收和有效CO ₂吸附的高效光催化剂。前两个可以通过用窄带隙半导体制造Z方案系统来实现，最后一个可以通过在催化剂中产生空位缺陷来实现。本文中，通过在ZnSe纳米粒子上外延生长CdSe制备了具有不同ZnSe / CdSe比的ZnSe / CdSe复合材料，在可见光照射下，其表现出比原始ZnSe更高的CO _2光还原性能。ZnSe / CdSe（前驱体比率Zn：Cd = 1：0.125）表现出最佳的CO收率（116.9μmolg ^-1），是原始ZnSe（3.5μmolg ）的33.4倍^-1）。电子自旋共振（ESR）和密度泛函理论（DFT）计算表明，ZnSe / CdSe界面处的电荷转移遵循Z路径。通过加载CdSe改善光收集可以进一步促进电荷产生。制备过程中产生的硒空位可以促进CO _2的吸附。