Electrochemical preparation and features of newly cross-stacking multi-layered reduced graphene oxide (rGO) and polyaniline (PANI) modified carbon-based electrode

Abstract

Carbon-based electrode as an economically benign choice is widely used in electrochemical or bio-electrochemical systems. However, its poor electrical conductivity that leading high overpotential and energy loss, especially in large scale facilities, remains a bottleneck for its application. Herein, a unique cross-stacking multi-layered reduced graphene oxide (rGO) and polyaniline (PANI) modified carbon brush is fabricated via one-step electro-depositing. In particular, the top-most layer of the modified electrode is orientated controlled to be rGO or PANI layer by adjusting the initial CV scanning in the positive or negative direction. As was indicated by cyclic voltammetry, the improved electrochemical activity is achieved by coupling the advantages of the highly conductive network offered by graphene with desirable stability provided by the well-dispersed deposition of nanoscale PANI particles. In comparison, the modified electrode with rGO on the top-most layer (L_rGO) showed higher degree of sp²-hybridized -C-C- ordered structure in Raman profile, lower O/C ratio in XPS analysis, higher Zeta potential (−2.05 mV) and more hydrophilic than unmodified one. Moreover, benefiting from the unique cross-stacking multi-layered matrix of rGO and PANI, the best electrochemical performance was achieved on the electrode L_rGO with high exerted electrochemical active surface area (ECSA) of 0.85 mF cm⁻², and the charge transfer resistance as low as 0.32 Ω. The findings of this study provide a guidance for the modification and application of carbon-based electrode using rGO and PANI, which potentially enables the scaling-up of carbon-based electrode in various (bio-) electrochemical systems with high electrochemical performance.