Hemin-intercalated layer-by-layer electropolymerized co-deposition of bisphenol A on carbon nanotubes for dual electrocatalysis towards ascorbate oxidation and oxygen reduction

Abstract

A hemin-intercalated bisphenol A (BPA) electropolymerized film (H-PBPA) is co-deposited on single-walled carbon nanotubes (CNTs) by repetitive differential pulse voltammetry to achieve a CNTs@H-PBPA electrode for the oxidation of ascorbate (AA) and the reduction of oxygen (O2) in fuel cells. Although hemin-based redox reactions are depressed during the growth of PBPA films, the addition of hemin can remarkably promote the oxidation of BPA and the formation of H-PBPA hybrids on CNTs. Compared with hemin or PBPA on CNTs, the as-prepared H-PBPA hybrids show higher redox activity and overall conductivity, and greater dual electrocatalysis towards ascorbate oxidation and oxygen reduction. While simultaneously employing CNTs@H-PBPA as anode and cathode, the ascorbate fuel cell exhibits a 0.75-fold, 2.50-fold or 23.7-fold increase in the maximum power output in contrast to that using CNTs@PBPA, CNTs@hemin or CNTs. The proposed ascorbate fuel cell has the advantages of mild and environment-friendly operational conditions, high stability and power density, and no requirement for noble metals and enzymes. This study presents the first example of carbon nanotube functionalization using hemin as binder and BPA electropolymerized film as redox mediators for biomass energy conversion and utilization.