Farah Fahim, Muhammad Ramzan, Beriham Basha, Asad ur Rehman Khan, Majid Niaz Akhtar, Sajawal ur Rehman Khan, Amal M. Al-Mohaimeed, Wedad A. Al-onazi, Abdul Rehman, M.S. Al-Buriahi
Herein, we report the sol-gel synthesis and characterizations of pure and Calcium (Ca) doped Bismuth ferrites (BiFeO3) for H2S gas sensing and Cr (VI) pollutant reduction. X-ray diffraction confirmed the rhombohedral structure along the RC3 space group of synthesized ferrites. Raman analysis and EDX spectroscopy confirmed the cooperation of Ca2+ ions in the host lattice. Contraction in optical bandgap was observed with increasing concentration of Ca2+ dopants. Sensitivity towards the reducing gas (H2S) recorded increased from ∼4.5 for pure BiFeO3 to ∼ 226 for 18 % Ca2+ doped BiFeO3. The response time of 18 % Ca2+ doped BiFeO3 remained very fast 1–2 s in 5 ppm–25 ppm exposure of H2S gas. The gas-responsive curves exhibited the p-type behavior of ferrites and such fast and improved response time was not reported in p-type semiconductors. Furthermore, the Cr (VI) dye degradation was recorded under the illumination of visible light and the 35W Xe arc lamp is taken as the source of visible light. The photodegradation of Cr (VI) improves significantly from 58 % for pure BiFeO3 to 90 % for 18 % Ca2+ doped BiFeO3. The photostability of 18 % Ca2+ doped BiFeO3 is well because the reduction of Cr (VI) recorded up to ∼64 % for 20 cycles. Substitution of Bi3+ with Ca2+ causes the oxygen vacancies and the amount of Fe3+ valance potentials altered significantly as well as 18 % Ca2+ doped BiFeO3 illustrated the iron (IV) higher amount state (Fe4+) with valence band at 2.47 eV and conduction band at 0.61 eV vs. normal hydrogen electrode. These findings depict that the 18 % divalent (Ca2+) doped BiFeO3 is an excellent candidate for H2S gas sensing and photocatalytic applications. © 2025 Elsevier Ltd and Techna Group S.r.l.
Institute of Chemistry, Baghdad ul Jadeed campus, The Islamia University of Bahawlpur, 63100, Pakistan; Institute of Physics, The Islamia University of Bahawlpur, Bahawalpur, 63100, Pakistan; Department of Physics, College of Sciences, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia; Department of Computer Science, National Textile University, Faisalabad, 37610, Pakistan; Department of Computer Science, National Textile University, Karachi Campus, Karachi, 74900, Pakistan; Department of Chemistry, College of Science, King Saud University, P.O. Box 22452, Riyadh, 11495, Saudi Arabia; Department of Physics, University of Strathclyde Glasgow, G4 0NG, United Kingdom; Department of Physics, Sakarya University, Sakarya, Turkey; Mechanical and Industrial Engineering Department, Engineering Faculty, Universitas Negeri Malang, 65145, Indonesia
