A Theoretical Perspective on Charge Separation and Transfer in Metal Oxide Photocatalysts for Water Splitting

Abstract

Semiconductor‐based photocatalytic decomposition of water is one of the most promising techniques to produce clean and renewable energy in the future. Photogenerated charge separation and transfer is considered as one of the crucial steps controlling the conversion efficiency of solar energy in heterogeneous photocatalysis. Many experimental methods have been developed to enhance the efficiency of this process, such as fabricating junction structures, manipulating exposed facets, and loading suitable cocatalysts. Besides a variety of time and spatial resolved spectroscopic techniques, density functional theory calculations have been widely used to explore the photoinduced charge dynamics due to the advances of relevant theory and methodologies along with the improved computer performance. This article reviews recent theoretical researches mainly by means of density functional theory calculations in the charge separation and transportation in metal oxide photocatalytic systems. We introduce some common theoretical and computational methods for investigating physicochemical properties of photocatalytic materials, discuss the charge mobility in bulk and surface of semiconductors, the interfacial charge transfer in junction structures, and the role of cocatalysts in complex photocatalysts, and then evaluate potential research directions for superior photocatalytic systems on the basis of computational investigation and theoretical comprehension of intrinsic properties.

An Experimental and Theoretical Study on the Effect of Silver Nanoparticles Concentration on the Structural, Morphological, Optical, and Electronic Properties of TiO2 Nanocrystals

“…Numerous theoretical investigations on TiO 2 photocatalysts have been performed during recent decades. Moreover, they have also been reviewed to support the experimental results [28][29][30][31][32][33][34][35][36][37]. The electronic structures of metal/TiO 2 interfaces have previously been studied by DFT calculations [38].…”

Photocatalytic, structural and optical properties of mixed anion solid solutions Ba3Sc2−xInxO5Cu2S2 and Ba3In2O5Cu2S2−ySey

“…54 In practice this means that Ba 3 In 2 O 5 Cu 2 S 2 and Ba 3 In 2 O 5 Cu 2 Se 2 will possess high electron mobility which will aid transport of photoexcited electrons to the surface of the material to perform catalysis. 55 The In-based systems may also be bipolar semiconductors, a property which has been shown to exist in delafossite CuInO 2 . 56,57 The modelled band structures provide insight into the observed experimental trends in the band gap.…”

Engineering 2D Materials for Photocatalytic Water-Splitting from a Theoretical Perspective

“…DFT calculations have made significant contributions to a deep understanding of electronic behavior and structure-performance relationships for photocatalytic materials. Recently, several great review studies on DFT calculations of semiconductor-based photocatalysts have been published [ 12 , 14 , 41 , 55 ]. Theoretical efforts have primarily focused on the first step in bandgap engineering, which includes doping foreign elements and developing solid solutions because photoexcited electrons and holes are generated only when the photocatalyst’s bandgap is lower than the incident photon energy.…”