Synthesis of an amorphous: Geobacter-manganese oxide biohybrid as an efficient water oxidation catalyst
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Environmental Biotechnology Research Group
Environmental Science and Engineering Program
Water Desalination and Reuse Research Center (WDRC)
KAUST Grant NumberURF/1/2985-01-01
Permanent link to this recordhttp://hdl.handle.net/10754/665702
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AbstractThe development of a low cost and efficient oxygen evolution reaction (OER) catalyst has paramount importance to meet the future sustainable energy demand. Nature's photosynthetic machinery deploy manganese-based complex in the photosystem II to oxidize water. Inspired by nature, herein, we synthesized a high performing manganese-based OER catalyst using an electrochemically active and iron-rich bacterium, Geobacter sulfurreducens. The as-synthesized biohybrid catalyst (amorphous Geobacter-Mn2O3) produced a current density of 10 mA cm-2at an overpotential of 290 ± 9 mV versus a reversible hydrogen electrode with a low Tafel slope of 59 mV dec-1. The catalyst exhibited remarkable stability, evidenced through a long-term chronopotentiometry experiment. Multiple evidence showed that G. sulfurreducens contributed OER active elements (iron and phosphorus) to the biohybrid catalyst, and the as-synthesized Geobacter-Mn2O3is amorphous. The amorphous structure of the biohybrid catalyst provided a large electrochemically active surface area and excess catalytic sites for the OER catalysis. In addition, Mn3+present in the biohybrid catalyst is believed to be the precursor for oxygen evolution. The OER activity of the biohybrid catalyst outperformed commercial-Mn2O3, commercial-IrO2and most of the benchmark precious OER catalysts, thus supporting its suitability for large-scale applications. The proposed green approach to synthesize a biohybrid catalyst paves a new avenue to develop robust and cost-effective electrocatalysts for energy-related applications.
CitationKalathil, S., Katuri, K. P., & Saikaly, P. E. (2020). Synthesis of an amorphous Geobacter-manganese oxide biohybrid as an efficient water oxidation catalyst. Green Chemistry, 22(17), 5610–5618. doi:10.1039/c9gc04353e
SponsorsThis work was supported by Competitive Research Grant (URF/1/2985-01-01) from King Abdullah University of Science and Technology (KAUST).
PublisherRoyal Society of Chemistry (RSC)
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