Facile grinding method synthesis of SnS2@HKUST-1 and SnS2@Ni-MOF for electrocatalytic hydrogen evolution

Abstract

The development of high-performance and highly stable electrocatalysts is crucial and challenging for the hydrogen evolution reaction (HER). MOFs complexed with SnS₂ can form complexes with inserted structures, and their large specific surface area and numerous pores favor mass transfer, exposing the S active sites to more SnS₂, improving the utilisation of the active sites and enhancing the catalytic activity for the HER. Structural collapse can be hindered to improve the stability of the HER composites. Herein, six different kinds of SnS₂ were synthesized by a hydrothermal method under discrete conditions, and SI8-SnS₂ was screened out to have optimal morphology and electrocatalytic performance. Two innovative SnS₂@Ni-MOF and SnS₂@HKUST-1 as efficient electrocatalysts were synthesized by a facile grinding method for hydrogen generation. SnS₂@Ni-MOF and SnS₂@HKUST-1 catalysts showed lower overpotentials of 117 mV and 142 mV at 10 mA cm⁻² (η10) and smaller Tafel slopes (58 mV dec⁻¹ and 93 mV dec⁻¹) than six different kinds of SnS₂, Ni-MOF and HKUST-1 in 0.5 M H₂SO₄. Meanwhile, the C_dl values for SnS₂@Ni-MOF and SnS₂@HKUST-1 were estimated to be 11.5 mF cm⁻² and 8.0 mF cm⁻², and the stabilities of SnS₂, Ni-MOF, HKUST-1, SnS₂@Ni-MOF, and SnS₂@HKUST-1 were tested at a current density of 10 mA cm⁻². The current densities of SnS₂@Ni-MOF and SnS₂@HKUST-1 were stable over 8 h compared to the pure samples, and SEM, XPS tests were run after the HER test, indicating that the materials have excellent electrocatalytic stability. The syntheses of SnS₂@Ni-MOF and SnS₂@HKUST-1 enhance their intrinsic catalytic activity, and the porous structure promotes mass transfer efficiency, thereby improving the HER performance, which will guide the development of new and promising electrocatalysts for HER.