Facile synthesis of a Ni3S2@C composite using cation exchange resin as an efficient catalyst to improve the kinetic properties of MgH2

• Ni 3 S 2 @C composites were prepared using cheap cation exchange resins and Ni(CH 3 COO) 2 ⋅4H 2 O. • The comprehensive hydrogen storage performance of MgH 2 was significantly improved by the addition of Ni 3 S 2 @C. • The hydrogenation apparent activation energy of MgH 2 -Ni 3 S 2 @C-4 was 39.6 kJ mol −1 . • The multi-phase (Mg/Mg 2 Ni, Mg/MgS, and Mg/C) interface provided more active sites to improve the hydrogen storage performance of MgH 2 . Carbon materials have excellent catalytic effects on the hydrogen storage performance of MgH 2 . Here, carbon-supported Ni 3 S 2 (denoted as Ni 3 S 2 @C) was synthesized by a facile chemical route using ion exchange resin and nickel acetate tetrahydrate as raw materials and then introduced to improve the hydrogen storage properties of MgH 2 . The results indicated the addition of 10 wt.% Ni 3 S 2 @C prepared by macroporous ion exchange resin can effectively improve the hydrogenation/dehydrogenation kinetic properties of MgH 2 . At 100 °C, the dehydrogenated MgH 2 Ni 3 S 2 @C-4 composite could absorb 5.68 wt.% H 2 . Additionally, the rehydrogenated MgH 2 Ni 3 S 2 @C-4 sample could release 6.35 wt.% H 2 at 275 °C. The dehydrogenation/hydrogenation enthalpy changes of MgH 2 Ni 3 S 2 @C-4 were calculated to be 78.5 kJ mol −1 /−74.7 kJ mol −1 , i.e., 11.0 kJ mol −1 /7.3 kJ mol −1 lower than those of MgH 2 . The improvement in the kinetic properties of MgH 2 was ascribed to the multi-phase catalytic action of C, Mg 2 Ni, and MgS, which were formed by the reaction between Ni 3 S 2 contained in the Ni 3 S 2 @C catalyst and Mg during the first hydrogen absorption–desorption process.