Rational Regulation of Electronic Structure in Layered Double Hydroxide Via Vanadium Incorporation to Trigger Highly Selective CO 2 Photoreduction to CH 4 .

To realize excellent selectivity of CH 4 in CO 2 photoreduction (CO 2 PR) is highly desirable, yet which is challenging due to the limited active sites for CH 4 generation and severe electron-hole recombination on photocatalysts. Herein, based on the theoretically calculated effects of vanadium incorporation into the laminate of layered double hydroxides (LDHs), V into NiAl-LDH to synthesize a series of LDHs with various V contents is introduced. NiV-LDH is revealed to afford a high CH 4 selectivity (78.9%), and extremely low H 2 selectivity (only 0.4%) under λ > 400 nm irradiation. By further tuning the molar ratio of Ni to V, a CH 4 selectivity of as high as 90.1% is achieved on Ni 4 V-LDH, and H 2 is completely prohibited on Ni 2 V-LDH. Fine structural characterizations and comprehensive optical and electrochemical studies uncover V incorporation creates the lower-valence Ni species as active sites for generating CH 4 , and enhances the generation, separation, and transfer of photogenerated carriers.