2D/2D combination effects of pBN/gC3N4/TiO2 nanocomposites for photocatalytic CO2 conversion with alternative cationic scavengers

In this study, a series of pBN/gCN and pBN/gCN/TiO2 ternary nanocomposites was successfully fabricated by integrating 2D porous boron nitride and 2D graphitic carbon nitride with TiO2 using different amounts of gCN. First-principles DFT calculations were used for the first time to explore the electronic structure and electron flow in the ternary nanocomposites. The successful junctions of pBN/gCN/TiO2 were determined by analytical techniques, and all the results agreed that pBN, gCN, and TiO2 had interfacial connections with the efficient separation of photogenerated electrons and holes, thereby supplying plentiful photoinduced electrons to CO2R. In the photocatalytic CO2 reduction test, the light source was the principal component of the reactor; thus, we used visible light of different intensities (15 W, 75 W, and 100 W). In NaHCO3 solvent with a TEA electron donor, the CH3OH rates over TBCN2 were 13.79, 15.59, and 14.02 %, respectively. The enhanced efficiency of photocatalytic CO2 reduction is not only explained by the excellent capture of CO2 and the activation performance of TBCN2 with 2D/2D junctions, but also by the rapid charge separation and transfer of photogenerated charge carriers. Hence, this work demonstrates the use of 2D pBN and gCN with TiO2 ternary nanocomposites as novel and efficient catalysts for CO2R.

Automated summary

In this study, pBN/gCN and pBN/gCN/TiO2 ternary nanocomposites were successfully fabricated and their electronic structure and electron flow were explored using first-principles DFT calculations. The results showed efficient separation of photogenerated electrons and holes in these materials, supplying abundant photoinduced electrons for CO2 reduction. The reaction rates under visible light varied from 13.79% to 15.59%. The enhanced efficiency of photocatalytic CO2 reduction can be attributed to the excellent capture of CO2, the activation performance of the 2D/2D structure, and the rapid charge separation and transfer of photogenerated charge carriers.