In-situ electro-organic conversion of lignocellulosic-biomass product-syringaldehyde to a MWCNT surface-confined hydroquinone electrocatalyst for biofuel cell and sensing of ascorbic acid applications

Abstract

The development of an alternate environmental friendly electrocatalyst suitable to replace the function of the ferrocene, ferricyanide and prussian blue-based redox-mediators is a challenging research interest. Herein, we introduced a novel method for synthesis of a highly redox-active surface-confined Hydroquinone on MWCNT modified glassy carbon electrode surface, GCE/MWCNT@H2Q using the earth-abundant lignocellulose-biomass product, syringaldehyde (Syn) by one-step potential cycling and potentiostatic polarization method in pH 7 phosphate buffer solution that can show an efficient ascorbic acid electrocatalytic signal better than the conventional redox-mediators suitable to use as an anode in biofuel cell and selective electrochemical sensor applications in neutral pH solution. This new electrode showed a well-defined redox peak at Eo′ = −0.15 V(A2/C2) and 0.0 V(A3/C3) vs Ag/AgCl corresponding to the redox-active molecular species of H2Q and its polymerized product, Poly-H2Q. Based on various physicochemical techniques like Raman, IR, TGA, DTA, TEM, GC–MS, H1-NMR and scanning electrochemical microscope imaging using substrate generation/tip-collection mode, it has been revealed that Syn-precursor underwent a demethoxylation and hydration upon the electrochemical preparation condition. It has been proposed that the Poly-H2Q is an active site for the selective electrocatalytic oxidation of AA in a neutral pH solution.