YANG L C, LIU H J, LIU L, et al． Study on structural regulation and photodegradation performance of metal ion-doped α-Fe₂O₃[J]. Journal of Henan Polytechnic University( Natural Science) ， doi: 10.16186/j.cnki.1673-9787.2026010059.

doi: 10.16186/j.cnki.1673-9787.2026010059.

Received：2026-01-27

Revised：2026-03-30

Published：2026-07-06

Study on structural regulation and photodegradation performance of metal ion-doped α-Fe₂O₃

Yang Linchao1, Liu Huijun1, Liu Lei1, Zhu Chen2,  Liu Bin1, Li Zhangji1, Zhang Guiming1, Wang Conghui2

1. China Tobacco Henan Industrial Co., Ltd., Nanyang 473007, Henan, China; 2. College of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou 450001, Henan, China

Abstract: Objectives Constructing high-performance α-Fe₂O₃ photocatalysts through metal ion doping and elucidating the dominant regulatory mechanisms of metal ion doping on α-Fe₂O₃ photocatalytic activity. Methods Different metal ion-doped α-Fe₂O₃ photocatalysts were constructed by introducing various metal ions (Al³⁺, Cr³⁺, Mn²⁺, Cu²⁺) during the growth process of cubic-like α-Fe₂O₃. The effects of doping on morphology and structure were investigated by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The optimal doping element and its corresponding doping concentration were screened by evaluating the influence of each doped metal on the photocatalytic degradation of Rhodamine B. The active radicals involved in the reaction were identified via free radical trapping experiments and electron paramagnetic resonance, The band gap structures of the catalysts were determined using UV-visible absorption spectroscopy and Mott-Schottky measurements. The separation and migration of photogenerated carriers were studied by photocurrent response, electrochemical impedance spectroscopy, and photoluminescence spectroscopy.. Finally, the regulation mechanism of each doped metal on the photocatalytic reaction was systematically elucidated. Results Al³⁺ doping transformed the cubic-like α-Fe₂O₃ to large-sized spindles, and the photodegradation rate constant decreased from 0.01327 min^-1 to 0.00816 min^-1. Cr³⁺ doping and Mn²⁺ doping yielded small-sized cubic-like α-Fe₂O₃, and the photodegradation rate constants increased to 0.04409 min^-1 and 0.01567 min^-1, respectively. Cu²⁺ doping had no obvious effect on morphology and size, but enhanced the photodegradation rate constant to 0.06579 min^-1, which was 4.95 times that of the pristine cubic-like α-Fe₂O₃. Conclusions For cubic-like α-Fe₂O₃, Al³⁺ and Mn²⁺ doping regulated the photocatalytic activity through the morphology effects, while Cr³⁺ doping functioned via a combination of electronic and morphology effects. In contrast, Cu²⁺ doping modulated photocatalytic activity primarily through the electronic effect. Cu²⁺ doping promoted the generation and separation of photogenerated charge carriers, enhanced interfacial charge transfer, suppressed charge recombination, and generated more reactive radicals, ,thereby achieving highly efficient photocatalytic decolorization and pollutant degradation.

Keywords: morphology control; metal ion doping; photo-Fenton reaction; high-chroma refractory wastewater