Abstract
Graphitic phase carbon nitride (g-C(3)N(4), abbreviated as CN) can be used as a photocatalyst to reduce the concentration of atmospheric carbon dioxide. However, there is still potential for improvement in the small band gap and carrier migration properties of intrinsic materials. K-B co-doped CN (KBCN) was investigated as a promising photocatalyst for carbon dioxide reduction via the Density Functional Theory (DFT) method. The electronic and optical properties of CN and KBCN indicate that doping K and B can improve the catalytic performance of CN by promoting charge migration and separation. In terms of the Gibbs free energy change, the CO(2) reduction reaction catalysed by KBCN results in CH(3)OH, and its optimal pathway is CO(2) → *CO(2) → *COOH → CO → *OCH → HCHO → *OCH(3) → CH(3)OH. Compared with CN, the doping elements K and B shift the rate-determining step from CO(2) → *CO(2) to *CO(2) → *COOH. The K and B elements co-doping tuned the charge distribution between the catalyst and the adsorbate and reduced the Gibbs free energy of the rate-determining step from 1.571 to 0.861 eV, suggesting that the CO(2) reduction activity of KBCN is superior to that of CN. Our work provides useful insights for the design of metallic-nonmetallic co-doped CN for photocatalytic CO(2) reduction (CO(2)PR) reactions.