A highly sustainable hydrothermal synthesized MnO2 as cathodic catalyst in solar photocatalytic fuel cell. (January 2021)

• Record Type: Journal Article
• Authors: Ong, Yong-Por; Ho, Li-Ngee; Ong, Soon-An; Banjuraizah, Johar; Ibrahim, Abdul Haqi; Thor, Shen-Hui; Yap, Kea-Lee
• Is Part Of: Chemosphere. Volume 263(2021)
• Publication Date: 2021-01
• Subjects: Photocatalytic fuel cell (PFC) -- Cathode -- Manganese (IV) oxide -- Oxygen reduction reaction (ORR) -- Recyclability; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128212
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A unidirectional flow solar photocatalytic fuel cell (PFC) was successfully developed for the first time to offer alternative for electricity generation and simultaneous wastewater treatment. This study was focused on the synthesis of α-, δ- and β-MnO2 by wet chemical hydrothermal method for application as the cathodic catalyst in PFC. The crystallographic evolution was performed by varying the ratios of KMnO4 to MnSO4 . The mechanism of the PFC with the MnO2 /C as cathode was also discussed. Results showed that the catalytic activity of MnO2 /C cathode was mainly predominated by their crystallographic structures which included Mn–O bond strength and tunnel size, following order of α- > δ- > β-MnO2 /C. Interestingly, it was discovered that the specific surface areas (SBET ) of different crystal phases did not give an impact on the PFC performance. However, the Pmax could be significantly influenced by the micropore surface area (Smicro ) in the comparison among α-MnO2 . Furthermore, the morphological transformation carried out by altering the hydrothermal duration demonstrated that the nanowire α-M3(24 h)/C with 1:1 ratio of KMnO4 and MnSO4 yielded excellent PFC performance with a Pmax of 2.8680 μW cm −2 and the lowest Rint of 700 Ω. Graphical abstract: Image 1 Highlights: Unidirectional flow solar PFC with MnO2 cathode was developed. Crystallographic structure of α-MnO2 dominated the PFC performance. Internal resistance was governed by the microstructural phase of MnO2 . Importance of morphological control for MnO2 as cathodic catalyst. Excellent sustainability of nanowire α-MnO2 /C for five cyclic runs.