Photoelectrochemical water splitting is the efficient means for solar-to-hydrogen conversion. α-Fe2O3 has been considered as promising candidate owing to its small band gap of 2.1~2.2 eV, excellent stability and a high theoretical STH efficiency. However, due to its short hole diffusion length, short lifetime and high overpotential for water oxidation, Fe2O3 has a very poor PEC performance. Generally, to improve PEC performance of Fe2O3, such problems as the sluggish charge transfer and high overpotential of the semiconductor are addressed through the strategies like element doping, oxygen vacancies, homojunction construction, cocatalyst decoration/surface passivation. However, how to extend the migration lifetime of carriers and increase the value of STH remains a huge challenge.
Due to this, the joint research team of Prof. Wu Limin with the College of Energy Materials and Chemistry of IMU and Prof. Wang Lei with the School of Chemistry and Chemical Engineering of IMU reported that it used single-atom-Pt-doped one-dimension nanostructure of α-Fe2O3 to increase the concentration of the semiconductor bulk carriers and constructed Pt-O-Fe bond to lower the density of states of deep-level defects and suppress the recombination of carriers caused by deep-level defects and the performance and onset potential of the semiconductor were remarkably improved. Compared with the traditional element doping, the value of the photocurrent of the single-atom doped α-Fe2O3 under the simulated sunlight can increase two fold. The research concerned has been published in Nature Communications online on May 8, 2023.
Key point 1. The single-atom Pt doping of α-Fe2O3 can induce few electron trapping sites, enhance carrier separation capability, and boost charge transfer lifetime in the bulk structure as well as improve charge carrier injection efficiency at the semiconductor/electrolyte interface. Further introduction of surface oxygen vacancies can suppress charge carrier recombination and boost surface reaction kinetics.
Key point 2. The optimum SAs Pt:Fe2O3-Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm−2 at 1.23 and 1.5 VRHE, respectively, with an applied bias photon-to-current efficiency of 0.68% for the hematite-based photoanodes.
This research demonstrates the effective strategy to design photoelectrocatalytic semiconductors.
Gao Ruiting, PhD candidate of the School of Chemistry and Chemical Engineering of IMU who was enrolled in the university in 2020, is the first author of the article. Prof. Wu Limin, Prof. Wang Lei and Research Fellow He Jinlu are the co-corresponding authors. The research was supported by Nanotechnology Program of the Ministry of Science and Technology of P.R.C., the National Natural Scientific Foundation of China, Inner Mongolia Autonomous Region Program for Grassland Talents and Inner Mongolia University Program for Young Scientific and Technological Talents.
