Abstract

Green hydrogen production via water-splitting technology holds promise for the future of a hydrogen-based economy and addresses climate change caused using fossil fuels. Current research focuses on developing new catalytic materials from abundant natural resources and cost-effective sources to replace noble metal-based catalysts. Among them, (MoS₂ is a potential catalyst for water splitting, which can be synthesized from molybdenum, a transition metal with high natural abundance. This paper presents the development of an electrochemical deposition process using the cyclic voltammetry (CV) method to fabricate molybdenum disulfide–molybdenum trioxide (MoS₂-MoO₃.H₂O) hybrid films on FTO substrates in a simple and low-cost single step. The initially amorphous films could crystallize at a relatively low temperature (120 ^oC), unlike conventional methods that required higher temperatures. Accordingly, a thin MoS₂-MoO₃^.H₂O film (500 nm) was electrochemically deposited on conductive glass FTO substrates (denoted MoS₂-MoO₃^.H₂O /FTO) from an electrolyte solution containing 5 mM (NH₄)₆Mo₇O₂₄ 30 g/L Na₂S and 0.1 M KCl using the CV method. The electrocatalytic activity of the MoS₂-MoO₃^.H₂O /FTO electrode for the hydrogen evolution reaction (HER) was evaluated in 0.5 M H₂SO₄ using linear sweep voltammetry (LSV). The films formed by CV exhibited a brown color and an amorphous structure. After the thermal treatment at 120 ^oC, the amorphous structure transformed into a crystalline structure, comprising MoS₂ and MoO₃^.H₂O phases. LSV results showed that the electrocatalytic activity of the electrode significantly improved after heat treatment at 120 °C, with a Tafel slope of 80 mV/dec and a 2.75-fold increase in current density compared to the untreated electrode. The fabricated MoS₂-MoO₃^.H₂O /FTO electrode exhibited high catalytic activity and stability in 0.5 M H₂SO₄ These results demonstrated that MoS₂-MoO₃^.H₂O /FTO was a promising, easily fabricated catalytic system suitable for green hydrogen applications.