Bimetallic Electrocatalyst of Hyaluronate-Au@Pt for Durable Oxygen Reduction in Biofuel Cells

Biofuel cells (BFCs) have attracted great attention as battery substitutes in wearable and implantable devices. Oxygen reduction enzymes such as bilirubin oxidase, laccase, and peroxidase are used as cathodic materials in enzymatic BFCs (EBFCs). However, the low power output and short lifetime of EBFCs have limited their further commercial applications. Here, a bimetallic electrocatalyst of hyaluronate-Au@Pt (HA-Au@Pt) was synthesized to enhance the oxygen reduction reaction (ORR) performance of EBFCs by modifying the electronic structure of Pt with high oxygen reduction. HA is a biocompatible, hydrophilic, and linear polysaccharide, which can be utilized as a binder and stabilizer to enhance the dispersibility, stability, and biocompatibility of Au@Pt for wearable and implantable devices. The open circuit voltage is 0.35 V and the maximum current density is −166 μA/cm2 at −0.04 V for the optimized HA-Au@Pt electrocatalyst with 0.5 mM H2PtCl6. In comparison with other biocompatible polymers, HA in HA-Au@Pt catalysts showed excellent dispersibility and remarkable durability under the ORR condition. The power density of a glucose oxidase-based EBFC appeared to be 15.8 μW/cm2 at 0.29 V, demonstrating the feasibility of HA-Au@Pt as a promising electrocatalyst in the energy generation of EBFCs.