Preparation of lantern-shaped Cu/ZnFe-LDH heterostructure and its photocatalytic CO2 reduction performance

In this work, the heterostructure between Cu particles and ZnFe-LDH semiconductor with lantern shape was constructed by reducing the ternary CuZnFe-LDH using H 2 , and the effects of Cu loading and the formation of heterojunction on photocatalytic CO 2 reduction to CO and CH 4 were investigated. The results showed that the hollow and layer-stacking structure of the catalyst was beneficial to the light utilization, adsorbing and activating of carbon dioxide. The Cu cations could enter into the lattice of ZnFe-LDH to form a ternary CuZnFe-LDH, which could be reduced to Cu particles with smaller size by H 2 and resulting in the heterostructure between Cu and ZnFe-LDH. The loading of Cu particles can significantly enhance the light absorption, photogenerated carriers transfer rate and separation efficiency of ZnFe-LDH, thus improving photocatalytic activity. As expected, Cu 1.6 ZnFe-R catalyst exhibited the highest catalytic activity with CO yield of 45.35 μmol·g cat −1 ·h −1 and CH 4 yield of 39.33 μmol·g cat −1 ·h −1 , which were 2.81 and 6.19 times higher than those of ZnFe-LDH, respectively. Meanwhile, Cu particles acted as electron-rich centers and CO 2 adsorption sites can noticeably improve the CH 4 selectivity and inhibit H 2 production. The Cu 1.6 ZnFe-R catalyst exhibits the highest CH 4 electron-based selectivity of 65.17 %, the highest electrons consumed of 482.80 μmoL·g cat −1 ·h −1 for CO 2 reduction and the lowest H 2 electron-based selectivity of 16.04 %.