Anion-exchange synthesis of an MnCo₂S₄ electrocatalyst towards facilitated ultralong hydrogen evolution reaction in acidic and alkaline media

Abstract

Hydrogen (H2) is deemed one of the prominent energy solutions of the 21st century owing to the significant scientific and technological efforts devoted to the realization of a renewable carbon-free H2-based economy.

Construction of NiCo2S4−xPx nanowire arrays for efficient hydrogen evolution reactions in both acidic and alkaline media

“…Therefore, P doping into NiCo 2 S 4 /CFP can effectively favor the HER kinetics both in acidic media and in alkaline media for the obtained NiCo 2 S 4− x P x /CFP. Meanwhile, the Tafel slope of the NiCo 2 S 4− x P x /CFP in alkaline media is located in the range of 40 to 120 mV dec −1 , which indicates the NiCo 2 S 4− x P x /CFP may follow the Volmer–Heyrovsky mechanism, 31,63 consistent with acidic media. The NiCo 2 S 4− x P x /CFP exhibits comparable or superior HER performances compared with other reported sulfide-based electrocatalysts in alkaline media, as indicated in Table S8 (ESI†).…”

“…60–63 The Tafel slopes of the NiCo 2 S 4− x P x /CFP and NiCo 2 S 4 /CFP are located in the range of 40 to 120 mV dec −1 , which certifies that both the NiCo 2 S 4− x P x /CFP and NiCo 2 S 4 /CFP possibly follow the Volmer–Heyrovsky mechanism during the HER process in acidic media according to relevant reports. 31,64 The NiCo 2 S 4− x P x /CFP presents comparable or superior HER performances compared with other reported sulfide-based electrocatalysts in acidic media, as indicated in Table S6 (ESI†).…”

“…Hitherto, a variety of non-noble metal-based catalysts have been developed, such as metal sulfides, 14,15 metal phosphides, 16,17 metal selenides, 18–20 metal carbides, 21,22 metal nitrides, 23,24 and so on. Recently, among metal sulfides, the ternary transition metal sulfides have been widely investigated as HER electrocatalysts, which usually exhibit rich redox active sites due to positive synergistic effects of different components and show more promising potential compared with binary metal sulfides, such as NiCo 2 S 4 , 25–28 CuCo 2 S 4 , 29,30 MnCo 2 S 4 , 31,32 CoMoS 4 , 33,34 and so on. Traditional NiCo 2 S 4 materials, as hot NiCo-based chalcogenides, display good electrical conductivity, 35,36 diverse nanostructures and preferable electrocatalytic activity, meanwhile exhibiting rich redox properties caused by multivalent states of Co and Ni components, 35,37 which have aroused researchers’ interest.…”