Vapor grown carbon fiber combined with polyaniline and gold nanoparticles in composite bioelectrodes and their application in glucose fuel cells

Abstract

In this work, glucose fuel cells (GFCs) employing two types of novel composite bioanodes, including polyaniline (PANI)/vapor grown carbon fiber (VGCF)/glucose oxidase (GOx) and gold nanoparticles (AuNPs)/VGCF/GOx, were reported for the first time. Considering the relatively high cost and toxicity of carbon nanotubes (CNTs) used in enzymatic composites, VGCF was investigated here, which has merits of low cost, less toxic characteristics and excellent electrical and mechanical properties. It was found that VGCF mixed very well with PANI and AuNPs could be attached onto VGCF. Both PANI/VGCF and AuNPs/VGCF showed good thermal stability, which were better than CNTs. The electron transfer rate constant (k_s) of the AuNPs/VGCF/GOx bioanode was also measured, which was high (3.2 s⁻¹) due to its good electrocatalytic activity. Investigation of their performance in GFCs showed that the maximum power density of a GFC using the PANI/VGCF/GOx bioanode was 22.26 μW cm⁻², which was 1.7% higher than that of a GFC with PANI/CNT/GOx under the same experimental conditions. Moreover, the GFC with AuNPs/VGCF/GOx had a higher maximum power density (26.04 μW cm⁻²) than that of a PANI/VGCF/GOx based GFC. Hence, VGCF could be a promising and ideal substitute for CNTs in GFC applications.