Energy and environmental applications of Sn4+/Ti4+ doped α-Fe2O3@Cu2O/CuO photoanode under optimized photoelectrochemical conditions

Lakshmana Reddy Nagappagari; Jaewon Lee; Hyeonkwon Lee; Beomgyun Jeong; Kiyoung Lee

doi:10.1016/j.envpol.2020.116318

Energy and environmental applications of Sn⁴⁺/Ti⁴⁺ doped α-Fe₂O₃@Cu₂O/CuO photoanode under optimized photoelectrochemical conditions

Environ Pollut. 2021 Feb 15:271:116318. doi: 10.1016/j.envpol.2020.116318. Epub 2020 Dec 15.

Authors

Lakshmana Reddy Nagappagari¹, Jaewon Lee², Hyeonkwon Lee³, Beomgyun Jeong⁴, Kiyoung Lee⁵

Affiliations

¹ School of Nano & Materials Science and Engineering, Kyungpook National University, 2559, Gyeongsang-daero, Sangju, Gyeongbuk, South Korea; Research Institute of Environmental Science & Technology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, South Korea.
² School of Nano & Materials Science and Engineering, Kyungpook National University, 2559, Gyeongsang-daero, Sangju, Gyeongbuk, South Korea; Research Institute of Environmental Science & Technology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, South Korea; Department of Advanced Science and Technology Convergence, Kyungpook National University, 37224, Sangju, Gyeongsangbuk-do, Republic of Korea.
³ Research Institute of Environmental Science & Technology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, South Korea.
⁴ Research Center for Materials Analysis, Korea Basic Science Institute, 34133, Daejeon, South Korea.
⁵ School of Nano & Materials Science and Engineering, Kyungpook National University, 2559, Gyeongsang-daero, Sangju, Gyeongbuk, South Korea; Research Institute of Environmental Science & Technology, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, South Korea; Department of Advanced Science and Technology Convergence, Kyungpook National University, 37224, Sangju, Gyeongsangbuk-do, Republic of Korea. Electronic address: kiyoung@knu.ac.kr.

PMID: 33360662
DOI: 10.1016/j.envpol.2020.116318

Abstract

The most promising technique for directly converting solar energy into clean fuels and environmental remediation by organic dye degradation is photoelectrochemical (PEC) process. We introduced Sn⁴⁺/Ti⁴⁺ doped α-Fe₂O₃@Cu_xO heterojunction photoanode with complete optimization for PEC hydrogen (H₂) generation and organic dye degradation. Improvement of photocurrent photo and reducing overpotentials under optimized conditions lead to enhancing PEC performances, degradation efficiency of organic compounds, and H₂ generation generation rate. The optimized heterojunction photoanode (5TiFe@Cu_xO-D) showed IPCE exceeding 42% compared with pristine hematite (Fe_0.01-800_6h) nanostructures (28%). Additionally, all the optimized photoanodes showed higher PEC stability for 10 h. Time-resolved PL spectra confirm the improved average lifetime for heterojunction photoanodes, supporting the enhanced PEC performance. Optimized 5TiFe@Cu_xO-D material achieved PEC H₂ generation of ∼300 μL h^-1.cm^-2 which is two times higher than pristine hematite's activity (150 μL h^-1.cm^-2) and almost 99% degradation efficiency within 120 min of irradiation time. Therefore, a state-of-the-art study has been explored for hematite-based heterojunction photoanodes reflecting the superior PEC performance and hydrogen, methyl orange (MO) dye degradation activities. The improved results were reported because of stable morphology and better crystallinity acquired through systematic investigation of thermal effects and hydrothermal duration, improved electrical properties by Sn/Ti doping into the lattice of α-Fe₂O₃ and optimization of Cu_xO deposition methods. The formation of well-defined heterojunction minimizes the recombination of the charge carrier and leads to effective transportation of excited electrons for the enhanced PEC performance.

Keywords: Charge transfer; Hematite; Heterojunction; Hydrogen generation; IPCE; Photoelectrochemical; Stability.

MeSH terms

Copper
Nanostructures*
Solar Energy*
Titanium

Substances

Copper
Titanium
cupric oxide