Prominent Conductor Mechanism-Induced Electron Transfer of Biochar Produced by Pyrolysis of Nickel-Enriched Biomass

Biochar is redox-active and can function as a sustainable electron shuttle in catalyzing relevant redox reactions. It plays a crucial role in environmental remediation. In this work, we used different-nickel (Ni)-level biochars produced by the pyrolysis of plant biomass with correspondingly different Ni levels as extracellular electron shuttles for microbial reduction of ferrihydrite by Shewanella oneidensis MR-1. A high Ni level of the precursor considerably enhanced the conductor mechanism of the produced biochar and thus enabled the biochar to catalyze increased microbial reductions of the Fe(III) mineral, but it did not promote the charging and discharging capacities of the produced biochar. This study can aid in the search for natural biomass with high Ni content to establish low-cost biochars with wide-ranging applications in catalyzing the redox-mediated reactions of pollutants.