Progress in the Preparation and Application of Electrocatalysts Based on Microorganisms as Intelligent Templates

The storage and conversion of renewable energy through electrocatalysis is of considerable significance for improving the energy structure, protecting the ecological environment, and achieving the national strategy of carbon peaking and carbon neutrality. The development of low-cost and high-efficiency electrocatalysts has become a major scientific challenge worldwide. Microorganisms are widely found in nature and are characterized by their rich structure, composition and metabolism. These properties facilitate their use as intelligent templates for electrocatalyst structures and as sources of non-metallic elements such as carbon, phosphorus, sulfur, as well as metallic elements. The use of microorganisms in electrocatalyst production has become a new trend owing to the advantages of non-toxicity, reproducible production, and ease of scaling up. Thus, this paper reviews the development of microbial "intelligence" guided preparation of electrocatalysts and their current applications in the fields of hydrogen evolution reactions, oxygen evolution reactions, oxygen reduction reactions, carbon dioxide reductions and lithium batteries. In order to achieve the function of "intelligent" guidance of microorganisms, four aspects need to be addressed: (1) the selection of suitable microbial species and the culture and activation conditions, which significantly helps in tailoring the microbial properties for specific applications; (2) the exploration of microbial species that can accumulate metal species from their living environment and thus produce metal nanoparticles, which will help obtain nanocomposites with desired properties; (3) the selection of compounds with good catalytic properties, high stability, and compatibility with microbial substrates; and (4) the development of highly controllable nanocatalysts through modern molecular biology and genetic engineering to regulate microbial life processes such as metabolic proliferation and apoptosis. With the resolution of these issues, we believe that the application of microbial intelligent templates guided electrocatalysts can be further extended to other electrocatalytic reactions such as ethanol oxidation reactions (EOR), nitrogen reduction reactions (NRR), and to other applications in fields such as electronics, sensing, imaging, and biomedicine. The goal of this review is to promote a deeper understanding of the correlations among microbial metabolism, catalyst micro-nano structures and structure-activity relationships. Furthermore, the challenges associated with such materials and the prospects for future development are discussed herein.