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Bioproduction of cerium-bearing magnetite and application to improve carbon-black supported platinum catalysts

DOI: 10.1186/s12951-024-02464-x DOI Help

Authors: Jinxin Xie (The University of Manchester) , Ziyu Zhao (The University of Manchester) , Victoria S. Coker (The University of Manchester) , Brian O'Driscoll (The University of Manchester; The University of Ottawa) , Rongsheng Cai (The University of Manchester) , Sarah J. Haigh (University of Manchester) , Stuart M. Holmes (The University of Manchester) , Jonathan R. Lloyd (The University of Manchester)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Nanobiotechnology , VOL 22

State: Published (Approved)
Published: April 2024

Open Access Open Access

Abstract: Background: Biogeochemical processing of metals including the fabrication of novel nanomaterials from metal contaminated waste streams by microbial cells is an area of intense interest in the environmental sciences. Results: Here we focus on the fate of Ce during the microbial reduction of a suite of Ce-bearing ferrihydrites with between 0.2 and 4.2 mol% Ce. Cerium K-edge X-ray absorption near edge structure (XANES) analyses showed that trivalent and tetravalent cerium co-existed, with a higher proportion of tetravalent cerium observed with increasing Ce-bearing of the ferrihydrite. The subsurface metal-reducing bacterium Geobacter sulfurreducens was used to bioreduce Ce-bearing ferrihydrite, and with 0.2 mol% and 0.5 mol% Ce, an Fe(II)-bearing mineral, magnetite (Fe(II)(III)2O4), formed alongside a small amount of goethite (FeOOH). At higher Ce-doping (1.4 mol% and 4.2 mol%) Fe(III) bioreduction was inhibited and goethite dominated the final products. During microbial Fe(III) reduction Ce was not released to solution, suggesting Ce remained associated with the Fe minerals during redox cycling, even at high Ce loadings. In addition, Fe L2,3 X-ray magnetic circular dichroism (XMCD) analyses suggested that Ce partially incorporated into the Fe(III) crystallographic sites in the magnetite. The use of Ce-bearing biomagnetite prepared in this study was tested for hydrogen fuel cell catalyst applications. Platinum/carbon black electrodes were fabricated, containing 10% biomagnetite with 0.2 mol% Ce in the catalyst. The addition of bioreduced Ce-magnetite improved the electrode durability when compared to a normal Pt/CB catalyst. Conclusion: Different concentrations of Ce can inhibit the bioreduction of Fe(III) minerals, resulting in the formation of different bioreduction products. Bioprocessing of Fe-minerals to form Ce-containing magnetite (potentially from waste sources) offers a sustainable route to the production of fuel cell catalysts with improved performance.

Diamond Keywords: Fuel Cells

Subject Areas: Environment, Materials, Biology and Bio-materials

Instruments: B18-Core EXAFS

Added On: 01/05/2024 12:23


Discipline Tags:

Energy Storage Desertification & Pollution Earth Sciences & Environment Biotechnology Mineralogy Energy Physical Chemistry Catalysis Energy Materials Chemistry Materials Science Engineering & Technology Geology Nanoscience/Nanotechnology Life Sciences & Biotech Geochemistry

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Absorption Near Edge Structure (XANES)