Regulating Oxygen Vacancies and Fermi Level of Mesoporous CeO 2-x for Intensified Built-In Electric Field and Boosted Charge Separation of Cs 3 Bi 2 Br 9 /CeO 2-x S-Scheme Heterojunction.
Zhijie ZhangXuesheng WangDeben LiYaoqing ChuJiayue XuPublished in: Small (Weinheim an der Bergstrasse, Germany) (2023)
Regulating the built-in electric field (BEF) in the heterojunction is is a great challenge in developing high-efficiency photocatalysts. Herein, by tailoring the content of oxygen vacancies in the constituent reduction semiconductor (mesoporous CeO 2-x ), a precise Fermi level (E F ) regulation of CeO 2-x is realized, yielding an amplified E F gap and intensified BEF in the Cs 3 Bi 2 Br 9 perovskite quantum dots/CeO 2-x S-scheme heterojunction. Such an enhanced BEF offers a strong driving force for directional electron transfer, boosting charge separation in the S-scheme heterojunction. As a result, the optimized Cs 3 Bi 2 Br 9 /CeO 2-x heterojunction delivers a remarkable CO 2 conversion efficiency, with an impressive CO production rate of 80.26 µmol g -1 h -1 and a high selectivity of 97.6%. The S-scheme charge transfer mode is corroborated comprehensively by density functional theory (DFT) calculations, in situ X-ray photoelectron spectroscopy (XPS), and photo-irradiated Kelvin probe force microscopy (KPFM). Moreover, diffuse reflectance infrared Fourier transform spectra (DRIFTS) and theoretical calculations are conducted cooperatively to reveal the CO 2 photoreduction pathway.
Keyphrases
- visible light
- density functional theory
- solar cells
- molecular dynamics
- high efficiency
- single molecule
- quantum dots
- electron transfer
- high resolution
- perovskite solar cells
- room temperature
- magnetic resonance
- dna methylation
- molecular dynamics simulations
- computed tomography
- sensitive detection
- liquid chromatography
- highly efficient
- mass spectrometry
- monte carlo