Ternary transition metal chalcogenides decorated on rGO as an efficient nanocatalyst towards urea electro-oxidation reaction for biofuel cell application

Abstract

A ternary transition metal chalcogenide, containing MoS2, NiS, and Co3S4 (MCNS), and MCNS/reduced graphene oxide (MCNS/rGO) composite were prepared as anode catalysts by a simple hydrothermal process for Urea electro-oxidation. It's expected that rGO with high specific surface area provides superior catalytic performance for MCNS/rGO than MCNS. Also, the synergic effect of Mo, Ni, and Co in the composite accelerates the urea oxidation and enhances the performance of the catalyst. The composites were characterized by field emission electron microscopy, transition electron microscopy, and X-ray diffraction spectroscopy. Electrochemical properties of composites were evaluated by cyclic voltammetry. The MCNS/rGO demonstrated superior electrocatalytic performance than the MCNS catalyst. The incorporating of rGO into MCNS creates a high electrochemical surface area for urea electro-oxidation that resulted in a higher current density (18 mA cm−2) than MCNS (3.7 mA cm−2) at the presence of 0.6 M urea and the scan rate of 20 mV s−1. The maximum current density obtained 43 mA cm−2 for MCNS/rGO at the scan rate of 70 mV s−1 in room temperature. Also, single cells based on MCNS and MCNS/rGO supplied a maximum power density of 7.7 mW cm−2 and 21.0 mW cm−2 at room temperature, respectively. Hence, MCNS/rGO can be a favorable electrocatalyst for application in the direct urea fuel cell.