Oxygen reduction activity of a Pt-N-4 single-atom catalyst prepared by electrochemical deposition and its bioelectrochemical application

The oxygen reduction reaction (ORR) is important in the field of energy conversion. Single-atom (SA) catalysts (SACs) exhibit good ORR catalytic effects and are widely used in electrocatalysis. Herein, we broaden the application of SACs in the field of bioelectrochemistry and study their electrocatalytic performance in air-cathode microbial fuel cells (MFCs). In this study, a platinum (Pt) SA-skin catalyst, boron-nitride-carbon (BCN) nanosheet with densely accessible Pt-N4 moieties named Pt SAs-BCN, was prepared by electrochemical deposition, which is more beneficial for large-scale industrial preparation of SACs. The obtained Pt SAs-BCN offered numerous active sites with adequate exposure, resulting in highly efficient and stable ORR activity. The participation of trace Pt SAs strengthens the electrocatalytic performance of BCN and reduces its charge transfer resistance. Remarkably, when employed as an air cathode in MFCs, the Pt SAs-BCN-modified MFC exhibited a maximum power generation capacity of 0.425 V and a maximum power density of 936.31 mW cm-2, while being able to run for two months without a violent performance drop. The application of SACs in the field of bioelectrochemistry achieves the purpose of energy conversion and has great potential for the bioelectrodegradation of organics.