Electrochemical one-pot fabrication of free-standing nanoporous NiCo/ ERGO composite as bifunctional electrocatalyst for enhanced water splitting

Abstract

This research introduces a novel electrode design for water-splitting applications, consisting of a NiCo alloy combined with electrochemically reduced graphene oxide (ERGO) to form a free-standing electrode. The fabrication involves electrochemical co-deposition of the components onto an indium tin oxide (ITO) substrate, followed by a hydrogen bubble-induced delamination step and electrochemical activation to enhance its performance. Structural analysis reveals that NiCo nanostructures dispersed on ERGO layers in a 3D porous framework exhibit exceptional electrocatalytic performance for the HER and OER. For the HER, overpotentials of 47 mV (acidic) and 80 mV (alkaline) are achieved at 10 mAcm-2 with Tafel slopes of 31 and 202 mVdec-1, respectively. The OER shows an overpotential of 275 mV at 10 mAcm-2 and a Tafel slope of 73 mVdec-1. As the cathode and anode, it maintains 10 mAcm-2 at a cell voltage of 1.54 V for over 24 h.