Enhanced photoelectrochemical water splitting and photocatalytic decomposition performance of visible light active MgMnO3 perovskite nanostructure

• Published in: International journal of hydrogen energy 2024-08, Vol.77, p.1074-1089
• Main Authors: Anusha, Hosakote Shankara, Jijoe, Samuel Prabagar, Tenzin, Thinley, Divya, Vinod, Anilkumar, Kotermane Mallikarjunappa, Yashas, Shivamurthy Ravindra, Sumana, Kumar, Wantala, Kitirote, Shivaraju, Harikaranahalli Puttaiah
• Format: Article
• Language: English
• Subjects: MgMnO3 catalyst; PEC water splitting; Photocatalytic degradation; Photoelectrode; Sol-gel synthesis; Water pollutant
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.06.265

Clean energy production and environmental remediation are imperative for sustainable future. Specially, exploration of multifunctional catalyst, for production of low-cost and eco-friendly hydrogen (H2) fuel as well as efficient decomposition of emerging pollutants are certainly needed. This study investigates magnesium manganese oxide (MgMnO3), a perovskite oxide, synthesized by simple citrate sol–gel technique, and its structural, morphological, optical, and photoelectrochemical properties were analyzed for the photodegradation of ciprofloxacin (CIP) antibiotic, methylene blue (MB) dye, and photoelectrochemical (PEC) water splitting. The cubic spinel crystal structure of MgMnO3 was confirmed through powder X-ray diffraction (XRD) analysis. FE-SEM images of the MgMnO3 material revealed a cauliflower-like morphology, consisting of an assembly of microspherical grains of varying sizes. UV–Vis spectroscopy exhibited broad absorption in the UV–Visible region, and the Tauc plot estimated a band gap of 1.54 eV. The MgMnO3 catalyst showed 88% and 96% for photodecomposition of CIP (10 mg/L) and MB (10 mg/L), respectively, using 35 mg and 30 mg of catalyst quantity over 90 min. In addition, MgMnO3 photoelectrode showcases superior photoelectrochemical behavior, exhibiting maximal photocurrent density of 13.21 mA cm−2 measured at 1.2 V vs. RHE and achieving a solar-to-hydrogen conversion efficiency of 2.45% compared to MgO and MnO2 photoelectrode. EIS measurements of MgMnO3 show enhanced charge transfer and recombination kinetics. Notably, the MgMnO3 electrode reveals outstanding photoelectrochemical durability, maintaining its stability even after continuous illumination for 9 h. Improved PEC properties could be attributed to wider light absorption, enhanced photo-induced charge-separations, and electron mobility. Thus, present study established an efficient and enduring multifunctional catalyst, catering photocatalytic degradation and PEC H2 generation. •MgMnO3 perovskite nanoarchitecture was synthesized using a citrate sol–gel technique.•Maximum degradation of 88% and 96% for the CIP and MB, respectively.•A remarkable photocurrent density of 13.21 mA cm−2 at 1.2 V vs. RHE was achieved.•High solar-to-hydrogen conversion efficiency of 2.45% with excellent stability up to 9 h.•EIS results show excellent charge transfer and transport properties.