Rationally Correcting Impurity Levels Positions Based on Electrostatic Potential Strategy for Photocatalytic Overall Water Splitting

TL;DR

This paper introduces a electrostatic potential-based strategy to accurately predict and tune impurity levels in photocatalysts, enhancing water splitting efficiency by improving redox ability and light absorption.

Contribution

It presents a novel approach that considers electrostatic potential changes to better control impurity levels in doping engineering for photocatalysis.

Findings

Impurity atoms alter electrostatic potential gradients and polarity.

Doping expands visible light absorption range.

Enhanced polarity improves redox ability and water splitting efficiency.

Abstract

Doping to induce suitable impurity levels is an effective strategy to achieve highly efficient photocatalytic overall water splitting (POWS). However, to predict the position of impurity levels, it is not enough to only depend on the projected density of states of the substituted atom in the traditional method. Herein, taking in phosphorus-doped g-C3N5 as a sample, we find that the impurity atom can change electrostatic potential gradient and polarity, then significantly affect the spatial electron density around the substituted atom, which further adjusts the impurity level position. Based on the redox potential requirement of POWS, we not only obtain suitable impurity levels, but also expand the visible light absorption range. Simultaneously, the strengthened polarity induced by doping further improve the redox ability of photogenerated carriers. Moreover, the enhanced surface dipoles obviously promote the adsorption and subsequent splitting of water molecules. Our study provides a more comprehensive view to realize accurate regulation of impurity levels in doping engineering and gives reasonable strategies for designing an excellent catalyst of POWS.