Heterostructure of 3D sea-grape-like MoS₂/graphene on carbon cloth for enhanced water splitting

MoS₂ has been widely used as a hydrogen evolution reaction (HER) electrocatalyst because of its unique characteristics, such as a tunable band gap, near-zero Gibbs free energy, and earth abundance. However, its low electrical conductivity and the electrochemically inert basal plane of MoS₂ decrease the HER performance. Herein, we used graphene and carbon cloth (CC) to boost the electrocatalytic activity of MoS₂. Using nickel electrodeposition and chemical vapor deposition (CVD) at high temperature, graphene was grown on carbon cloth (Gr/CC) and a sea-grape-like morphology was formed simultaneously. Finally, Gr/CC was covered up with MoS₂ using two-zone CVD (MoS₂/Gr/CC), resulting in a three-dimensional (3D) sea-grape-like heterostructure. The MoS₂/Gr/CC exhibits outstanding HER performance, with a suitable onset potential (50 mV), low ŋ₁₀ (91 mV, overpotential at 10 mA cm⁻²), high electrical double layer capacitance (C_dl; 239 mF cm⁻²), low Tafel slope value (48 mV dec⁻¹), and high stability in 0.5 M H₂SO₄ for two days at various overpotentials. The 3D sea-grape-like morphology and the synergistic effect of MoS₂ and graphene led to the enhanced electrocatalytic activity of MoS₂/Gr/CC, indicating much better HER performance than most electrocatalysts based on graphene and MoS₂.