Synthesis of biohybrid electrocatalysts using electroactive bacteria

  • Rodrigo J. Jimenez Sandoval

Student thesis: Doctoral Thesis


Environmental pollution and health problems created by fossil fuels have led to the development of alternative energies such as solar and wind energies, hydroelectric power, and green hydrogen. The use of biohybrid materials in the development of this type of alternative energies is recent. Biohybrid materials are a unique type of advanced materials that have a biological component that can be a biomolecule or a whole cell and an abiotic or non-biological component that can be a ceramic, a synthetic polymer, or a metal, among others. They have applications in different fields that range from construction (such as bioconcrete) to catalysis (such as artificial enzymes). There are examples in the literature in which bacteria are hybridized with reduced graphene oxide or manganese oxide to catalyze the oxygen evolution of the electrochemical water splitting reaction that produces green hydrogen. The focus of this dissertation is to synthesize efficient biohybrid catalysts following a whole cell approach using electroactive bacteria as the biological component and metallic precursors that form particles ranging from single atoms, nanoclusters, and nanoparticles as the abiotic component. The Fe molecule that is part of the heme group of C-type cytochromes in the outer membrane of Geobacter sulfurreducens acted as the reduction center that allowed the synthesis and hybridization of the metals with the bacteria. Single atom metal catalyst of Ir, Pt, Ru, Cu, and Pd were synthesized and demonstrated a bifunctional catalytic activity towards the hydrogen evolution reaction and the oxygen evolution reaction. Ni single atoms were also synthesized with excellent activity in the water splitting reactions making this biohybrid catalyst very efficient but also green, as Ni is an abundant and cheap metal. Pd nanoclusters with size-control were synthesized by controlling the metal concentration, dosing, and incubation times and were tested in the electrochemical water splitting. Overall, the findings of these studies provide new knowledge on the field of biohybrid materials by contributing with novel methodologies for the synthesis of these materials and the application in the green hydrogen production with high efficiencies.
Date of AwardMar 2023
Original languageEnglish (US)
Awarding Institution
  • Biological, Environmental Sciences and Engineering
SupervisorPascal Saikaly (Supervisor)


  • Biohybrid materials
  • electrocatalysis
  • hydrogen evolution reaction
  • oxygen evolution reaction
  • Geobacter sulfurreducens
  • nanoparticles

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