Improved electrocatalytic performance of TiS2 by nanohybrid with MoC nanosheets towards overall water-splitting for green hydrogen

Abstract

The depletion of conventional resources has enhanced researchers’ interest in searching for renewable energy sources. Due to the zero-emission of by-products, there is a strong demand for H₂ production by typical water electrolysis. In this study, we demonstrated that a composite strategy of dual transition metal functional (MoC-TiS₂) was prepared for the first time as a bifunctional electrocatalyst via a hydrothermal route and used in three and two electrolyser setups. Using analytical tools like XRD, SEM/EDX, and XPS, phase purity, morphology, and valances of synthesized electrocatalysts are characterized. Combined with pure MoC and TiS₂ samples, microspheres with numerous sheets-like MoC-TiS₂ exhibited superior overall water splitting performance at OER overpotential of 130 mV and HER overpotential of 84 mV, along with small Tafel slopes (82 mVdec^-1@OER & 45 mVdec^-1@HER). The EIS study suggests that the small resistive values of MoC-TiS₂ endow high conductivity with improved electrochemical performance. The interaction induces a charge shift from Ti³⁺/Ti⁴⁺ to Mo²⁺/Mo⁶⁺ across cationic-anionic bonds regulated by the number of hetero-interfaces between MoC and TiS₂ and oxygen vacancies. Serving as a robust bifunctional electrode in a two-electrode configuration for an alkaline water electrolyzer, the MoC-TiS₂ attained benchmark current density by a cell voltage of 1.44 V and maintains its stable performance for at least 185 h. The present study presents a novel bifunctional efficient/durable electrocatalysts for practical water electrolysis application.