Theoretical study on photocatalytic CO2 reduction to CH4 on MgAl-LDH/JUC-505 heterojunction

Abstract

Photocatalytic technology represents a promising solution to address both the global energy crisis and the growing concerns of environmental pollution. The photocatalytic performance of single materials often falls short of meeting the required performance standards for practical applications. The development of composite materials offers significant advantages in overcoming the inherent performance limitations of single-material photocatalysts. In this study, we investigated the electronic properties and catalytic mechanisms of the heterojunction composed of two-dimensional (2D) layered double hydroxides and covalent organic frameworks, named MgAl-LDH/JUC-505 using density functional theory (DFT). Through an analysis of electron transfer at the interface and the band edge positions, we identified the system as an S-scheme photocatalytic mechanism. Compared to single-material photocatalysts, the catalytic performance of the heterojunction is significantly enhanced. The calculation of Gibbs free energy changes reveals that the maximum energy barrier is reduced by 0.76 eV. Theoretical calculations demonstrate that the MgAl-LDH/JUC-505 heterojunction holds significant potential for enhancing photocatalytic CO2 reduction. This study also establishes a solid theoretical foundation for future research in this area.