Novel Pt-carbon core–shell decorated hierarchical CoMo2S4 as efficient electrocatalysts for alkaline/seawater hydrogen evolution reaction

[Display omitted] •Pt-carbon core–shell coated on hierarchically grown CoMo2S4-GNF.•PC@CMS-NG shows strong metal–metal interactions between Pt and CoMo2S4.•PC@CMS-NG shows improved electrochemical HER performances (Eη10 = 27 mV).•Water splitting device achieved 10 mA cm−2 at 1.54 V in alkaline seawater medium. Electrochemical water electrolysis is a prominent method of green-hydrogen fuel production. Tailored nanostructures of Pt-based electrocatalysts have high priority in hydrogen production. Herein, we fabricated carbon-encapsulated Pt core–shell supported CoMo2S4-NGNF as an efficient electrocatalyst for the hydrogen evolution reaction (HER). The novel carbon-encapsulated Pt core shells improved the long-term durability. The Pt@CoMo2S4-NGNF hybrids displayed overpotentials of 27 mV to achieve a current density of 10 mA cm−2in 1.0 M KOH and outstanding durability of 100 h. When Pt@CoMo2S4-NGNF∥IrO2 was employed in overall seawater electrolysis applications, it required 1.54 V to achieve a 10 mA cm−2current density. Additionally, we evaluated the electronic structure and HER mechanism of Pt@CoMo2S4 & CoMo2S4 using density functional theory (DFT) calculations. This work illustrates the possibility of designing an effective, long-lasting, and scalable electrocatalyst for the electrolysis of alkaline and seawater to produce pure hydrogen.