VO4-Modified Layered Double Hydroxides Nanosheets for Highly Selective Photocatalytic CO2 Reduction to C1 Products

The conversion of CO2 into high-value added chemicals driven by solar energy is an effective way to solve environmental problems, which is, however, largely restricted by the competition reaction of the hydrogen evolution reaction (HER) and easy electron-hole recombination, etc. Herein, VO4-supported ultrathin NiMgV-layered double hydroxide (V/NiMgV-LDH) nanosheets are successfully fabricated, and the extended X-ray absorption fine structure (EXAFS) and density function theory (DFT) calculations reveal that VO4 species are located on the top of V atoms in the NiMgV-LDH laminate. The V/NiMgV-LDH is proved to be highly efficient for the photocatalytic CO2 reduction reaction (CO2PR) with high selectivity of 99% for C1 products and nearly no HER (<1%) takes place under visible light. Contrast experiments using NiMgV-LDH as the catalyst for CO2PR show a CO selectivity of 71.40% and a H-2 selectivity of 28.11%. Such excellent performance of V/NiMgV-LDH can be attributed to the following reasons: 1) the V/NiMgV-LDH modulates the band structure and promotes the separation of electrons and holes; 2) strong bonding between V/NiMgV-LDH and CO* and H* facilitates the hydrogenation to form CH4 and inhibits the formation of by-product H-2 at the same time.

Automated summary

This study investigates the conversion of CO2 into high-value added chemicals driven by solar energy. The results show that the use of VO4-supported ultrathin NiMgV-layered double hydroxide as a catalyst achieves high efficiency and selectivity for the photocatalytic CO2 reduction reaction under visible light. The excellent performance of V/NiMgV-LDH can be attributed to its modulation of the band structure, promotion of electron-hole separation, and strong bonding with CO* and H* to facilitate hydrogenation and inhibit the formation of by-product H-2.