synergistic effect

Applied catalysis. B, Environmental

(Note: Representative Cu(I) and Sn(II) atoms were artificially selected for color modification to make the reaction more clearly). • Cu 3 SnS 4 containing S vacancy accompanied with different ratios of Cu(I/II) and Sn(II/IV) was synthetized successfully. • High selectivity of CH 4 was achieved upon the existence S vacancy. • High performance of CO 2 photoreduction was obtained due to the formation of Sn(II) orbitals. • The reduction path of CO 2 →COOH*→CO*→CHO*→CH 2 O*→CH 3 O*→CH 4 was identified by DFT calculation. Cu 3 SnS 4 with S vacancy and different ratios of Cu(I/II) and Sn(II/IV) was designed for photocatalytic CO 2 reduction with high selectivity and activity in this study. The conduction band (CB) position dominated by the Sn(II) 5p orbital of Cu 3 SnS 4 could be regulated via controlling the content of Sn(II). Cu(I) and Sn(IV) in crystal lattice acted as the adsorption sites of CO 2 and H 2 O as demonstrated by Density Functional Theory (DFT) calculations, meanwhile Cu(I) had a strong adsorption ability to CO, which was conducive to further protonation for CH 4 generation (CO 2 →COOH*→CO*→CHO*→CH 2 O*→CH 3 O*→CH 4 ). S vacancy could result in the appearance of Cu(I) and Sn(II), which could successfully inhibit the electron-hole recombination and improve the reactivity (CH 4 with yield of 22.65 μmol/g/h) and selectivity (CH 4 ∼ 83.10 %). This work can shed some light on the synthetic method by controlling vacancy and elements to adjust CB position to increase reduction capability and selectivity.

Effect of S vacancy in Cu3SnS4 on high selectivity and activity of photocatalytic CO2 reduction