Nitrogen-doped carbon black supported NiCo2S4 catalyst for hydrogenation of nitrophenols under mild conditions

Catalytic hydrogenation of nitrophenols to aminophenols was considered as the most efficient way to solve their contamination together with huge economic benefit. NiCo 2 S 4 can be used not only as supercapacitor materials, but also competitive catalytic materials in hydrogenation reactions. In this work, a nitrogen-doped carbon black (NCB) supported NiCo 2 S 4 catalyst is successfully prepared by a facile one-pot solvothermal approach. TEM results show that the ultrafine NiCo 2 S 4 particles are uniformly dispersed on the surface of NCB at a low NiCo 2 S 4 loading, while aggregation may occur in NiCo 2 S 4 /NCB catalysts with an excessive NiCo 2 S 4 content. The NiCo 2 S 4 -30/NCB catalyst with a BET surface area of 47.20 m 2  g −1 exhibits the most excellent catalytic activity and durability for heterogeneous catalytic hydrogenation of nitrophenols using NaBH 4 as the reducing agent at 30 °C in the aqueous solution. The kinetic constant of hydrogenation of p -nitrophenol catalyzed by NiCo 2 S 4 -30/NCB is almost five times higher than the reaction catalyzed by pristine NiCo 2 S 4 . The outstanding performance of NiCo 2 S 4 -30/NCB is ascribed to the unique nanostructure of the catalyst and the combined effect between the NiCo 2 S 4 and NCB, including abundant surface functional groups of NCB for anchoring and dispersing NiCo 2 S 4 , strong adsorption ability for nitrophenol molecules facilitated by π–π stacking interaction, as well as fast electron transfer from NCB to NiCo 2 S 4 , resulting in higher local electron densities and thus facilitating the uptake of electrons by nitrophenols.