Affiliation:
1. Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission Key Laboratory of Photosensitive Materials and Devices of Liaoning Province School of Physics and Materials Engineering, Dalian Minzu University 18 Liaohe West Road Dalian 116600 P. R. China
2. Dalian Key Laboratory of Low‐Dimensional Semiconductor Optoelectronic Materials and Applications School of Physics and Materials Engineering Dalian Minzu University 18 Liaohe West Road Dalian 116600 P. R. China
3. Faculty of Materials and Manufacturing Beijing Key Lab of Microstructure and Properties of Advanced Materials Beijing University of Technology Beijing 100124 P. R. China
Abstract
AbstractSemiconductor quantum wells (QWs) exhibit high charge‐utilization efficiency for light‐emitting applications due to their strong charge confinement effect. Inspired by this effect, herein, this work proposes a new idea to significantly improve the photo‐generated charge separation for attaining a highly‐efficient solar‐to‐fuels conversion process through “semi‐reversing” the conventional QWs to confine only the photo‐generated electrons. This electron confinement‐improved charge separation is implemented in the well‐designed model of the CdS/TiO2/CdS semi‐reversed QW (SRQW) structure. The latter is fabricated by selectively assembling CdS quantum dots (QDs) onto the {101} facets (ultra‐thin edge regions) of the TiO2 nanosheets (NSs). Upon light excitation, the photo‐generated electrons of SRQW can be confined on the TiO2‐{101} facets in the vicinity of the CdS/TiO2 hetero‐interface. Thereby, the continuous multi‐electron injection to the adsorbed reactants on the interfacial active‐sites is significantly accelerated. Thus, the CdS/TiO2/CdS SRQW exhibits ≈35.7 and ≈56.0‐fold enhancements on the photocatalytic activities for water and CO2 reduction, respectively, compared to those of pure TiO2. Correspondingly, its CH4‐product selectivity is increased by ≈180%. This work provides a novel charge separation mechanism, which is of great importance for the design of the next‐generation quantum‐sized photocatalysts for solar‐to‐fuels conversion.
Funder
National Natural Science Foundation of China
Liaoning Revitalization Talents Program
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science