Metal-organic framework-erythrocytic hybrid surfaces with enhanced oxygen reduction performance for enzymatic biofuel cells–An updated strategy

Abstract

Enzymatic biofuel cells (EBFCs), which can use oxygen in the body as a cathode fuel to generate electricity, have broad application prospects. For air cathode of EBFCs, the most important factors affecting the electrocatalytic performance are the inherent fragile nature, poor oxygen enrichment performance and low activity of enzyme catalysts. Herein, based on the natural oxygen enrichment performance of red blood cells (RBCs) and its electrocatalytic activity for oxygen reduction reaction, we fabricate the hybrid surfaces of metal–organic framework-nanocoated RBCs (RBC@ZIF-8) using an in situ synthesis method. Versus native RBCs, the electrocatalytic activity and stability of RBC@ZIF-8 are enhanced by 50% and 35%, respectively, when explored as a biocathode catalyst for implantable biofuel cells. And compared with enzyme catalysts, RBC@ZIF-8 has better stability and handleability. Mechanistic studies show that the coating surface increases the O2-enriched capacity of RBCs and then provides more reaction raw materials for the hemoglobin with catalytic active. Moreover, direct electron transfer capability of RBC@ZIF-8 is found on carbon cloth electrode without promoters and mediators. Our research expands the types of air cathode catalyst for EBFCs and suggests a promising strategy to enhance the electrocatalytic performance of gas-based biocatalysts, such as bioelectrocatalytic reduction of CO2 and N2.