Tin and Oxygen-Vacancy Co-doping into Hematite Photoanode for Improved Photoelectrochemical Performances

Nanoscale Research Letters

Chenhong Xiao¹  Liujing Li¹  Shaolong Wu¹  Zhongyuan Zhou¹  Xiaofeng Li¹ 

[1]School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, 215006, Suzhou, Jiangsu, China

[2]Key Laboratory of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Laboratory of Modern Optical Technologies of Education Ministry of China, Soochow University, 215006, Suzhou, Jiangsu, China

关键词: Hematite;    Photoelectrochemical water splitting;    Ultrasonic spray pyrolysis;    Sn doping;    Oxygen vacancy;   

DOI  :  10.1186/s11671-020-3287-1

来源: Springer

【 摘 要 】

Hematite (α-Fe2O3) material is regarded as a promising candidate for solar-driven water splitting because of the low cost, chemical stability, and appropriate bandgap; however, the corresponding system performances are limited by the poor electrical conductivity, short diffusion length of minority carrier, and sluggish oxygen evolution reaction. Here, we introduce the in situ Sn doping into the nanoworm-like α-Fe2O3 film with ultrasonic spray pyrolysis method. We show that the current density at 1.23 V vs. RHE (Jph@1.23V) under one-sun illumination can be improved from 10 to 130 μA/cm2 after optimizing the Sn dopant density. Moreover, Jph@1.23V can be further enhanced 25-folds compared to the untreated counterpart via the post-rapid thermal process (RTP), which is used to introduce the defect doping of oxygen vacancy. Photoelectrochemical impedance spectrum and Mott-Schottky analysis indicate that the performance improvement can be ascribed to the increased carrier density and the decreased resistances for the charge trapping on the surface states and the surface charge transferring into the electrolyte. X-ray photoelectron spectrum and X-ray diffraction confirm the existence of Sn and oxygen vacancy, and the potential influences of varying levels of Sn doping and oxygen vacancy are discussed. Our work points out one universal approach to efficiently improve the photoelectrochemical performances of the metal oxide semiconductors.

【 授权许可】

CC BY