Chun Hong Mak, Yong Peng, Man Hin Chong, Jinhua Mou, Guohua Jia, Shella Permatasari Santoso, Wenxin Niu, Duu-Jong Lee, Chang-Ping Yu, Carol Sze Ki Lin, Hsien-Yi Hsu
An effective approach to enhance bioelectrochemical systems' performance involves leveraging semiconductors' light-harvesting capabilities alongside the catalytic properties of bacteria. Here, we demonstrate a food waste removal method using the integration of Shewanella oneidensis MR-1 with a tungsten(vi) oxide (WO3) nanoplate photoanode in a solar-assisted microbial photoelectrochemical cell (S-MPEC) combined with silicon-based photovoltaics (SiPV). The S-MPEC integrates the technologies of bioelectrochemical cells with photoelectrochemical cells (PEC) to enhance the degradation of food waste. The bare WO3 photoelectrode exhibits a photocurrent of 0.749 A m−2 at 0.8 V under visible light, whereas the WO3-MR-1 biophotoelectrode reveals a significantly higher photocurrent of 2.94 A m−2. Under visible light exposure at an intensity of less than 100 mW cm−2, the power densities of the WO3 photoelectrode with and without MR-1 bacterial coating are 2.36 W m−2 and 0.599 W m−2, respectively. To further improve performance, the S-MPEC was connected with a SiPV. This combined system, PV-S-MPEC, achieved a power density of 21.99 W m−2 and a chemical oxygen demand (COD) removal rate of 8167 mg L−1 per day, demonstrating its effectiveness in degrading food waste hydrolysate. Additionally, the study of heterogeneous electron transfer kinetics indicated that the WO3-MR-1 system exhibits more efficient diffusion coefficients and enhanced rate constants for reduction and oxidation reactions. These findings highlight the significant impact of photoexcited charge carriers on degradation performance in this complex hybrid electricigen system, underscoring its potential for developing S-MPECs for waste degradation. This study also demonstrates significant potential for reducing environmental impact through enhanced COD removal rates and energy-efficient waste processing, making it a viable solution for large-scale applications in urban waste management. © 2025 RSC.
School of Energy and Environment, City University of Hong Kong, Kowloon Tong, Hong Kong; Department of Materials Science and Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong; Department of Mechanical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong; Centre for Functional Photonics (CFP), City University of Hong Kong, Kowloon Tong, Hong Kong; Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, China; Curtin Institute of Functional Molecules and Interfaces, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, 6845, WA, Australia; Department of Chemical Engineering, Faculty of Engineering, Widya Mandala Surabaya Catholic University, Kalijudan No. 37, East Java, Surabaya, 60114, Indonesia; State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Jilin 130022, Changchun, China; Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, 10617, Taiwan