Role of Defects in Photocatalytic Water Splitting: Monodoped vs Codoped SrTiO$_3$

TL;DR

This study investigates how doping SrTiO$_3$ with different elements affects its ability to split water using light, finding that codoping with Mn and N significantly improves photocatalytic performance under visible light.

Contribution

The paper demonstrates that codoping SrTiO$_3$ with Mn and N effectively enhances its photocatalytic activity by suppressing charge recombination and improving charge mobility.

Findings

Monodoping with N or Mn induces visible light absorption but does not improve activity.

Codoping with Mn and N suppresses charge recombination and enhances mobility.

Mn$_{ extrm{Sr}} extrm{N}_ extrm{O}$ is identified as the most promising doped material.

Abstract

Using the hybrid density functional theory and \textit{ab initio} atomistic thermodynamics, we report monodoping of non-metal (N) or metal (Mn) in SrTiO$_3$ can induce visible light absorption, but none of them are suitable to ameliorate the photocatalytic activity. Therefore, in order to achieve enhanced photocatalytic activity of SrTiO$_3$, we have employed codoped Mn and N simultaneously in SrTiO$_3$ to modulate its electronic properties effectively. In the codoped SrTiO$_3$, the recombination of photogenerated charge carriers is suppressed, and the diffusion and mobility are increased owing to the passivation of discrete localized states. Our results reveal that Mn$_{\textrm{Sr}}\textrm{N}_\textrm{O}$ (codoping of Mn at Sr site and N at O site) is the most promising candidate for enhancing the photocatalytic activity of SrTiO$_3$ under visible light.