Insights into the interactions of g-C3N4/LaMnO3 hetero-junction to their structures and electronic properties by DFT calculations

Abstract

The hetero-junctions of LaMnO3 and g-C3N4 nano-materials are expected to have suitable band structure for the Z-scheme mechanism, but the electronic structures and interfaces have been scarcely studied. In this work, g-C3N4/LaMnO3 hetero-junction composed of g-C3N4 and LaMnO3 layers is studied using the DFT calculations with plane-wave ultrasoft pseudopotential basis sets. The calculated g-C3N4/LaMnO3 heterostructure has a small lattice-mismatch compared with LaMnO3 and g-C3N4. There are reformed Mn-N bonds across the interface, which indicates the strong interaction existing in two layers between LaMnO3 and g-C3N4. When g-C3N4 and LaMnO3 are in contact, the electrons will transfer from LaMnO3 layer to g-C3N4 layer. On the basis of the band structure analysis, the photo-generated electrons in LaMnO3 can combine with the photo-induced holes in g-C3N4, which leads the higher reduction ability of photo-generated electrons in g-C3N4, and the stronger oxidation of photo-induced holes in LaMnO3. As a result, the Z-scheme heterojunction could be generated between the g-C3N4 layer and LaMnO3 layer, which not only has the better visible light adsorption capability, but also the more efficient charge carrier separation.