Transition Metals Co, Ni, Mn Based Bimetallic Sulfides as an Efficient Electrocatalyst for Hydrogen Evolution Using Graphite Counter Electrode Extracted from Spent Battery

Abstract

The clean and green hydrogen energy production by electrochemical process is gaining great attention in recent years. For this, designing an efficient and cost-effective electrocatalyst for the hydrogen evolution reaction (HER) is highly desirable. Herein, Co-Ni-Mn based bimetallic sulfides electrocatalysts are developed for HER in 1 M KOH. Owing to the presence of abundant electrochemical active sites and micro flower-like morphology, the fabricated Co-Ni-S, Ni-Mn-S, Co-Mn-S electrodes deliver the small overpotential of 136, 112, 75 mV to reach the current density of 10 mA cm−2. For practical applications, the commercially available 1.6 V battery is used to drive the overall water splitting process of the device fabricated with the two-electrode system (symmetric device). In addition to this, in this research work, a graphite rod extracted from a spent battery is directly used as a counter electrode for the entire electrochemical study to substitute platinum (Pt) counter electrode. This approach is sustainable as well as eco-friendly.