Tuning Interfacial Active Sites over Porous Mo₂N-Supported Cobalt Sulfides for Efficient Hydrogen Evolution Reactions in Acid and Alkaline Electrolytes

Abstract

Although various cobalt-sulfide-based materials have been reported for the hydrogen evolution reaction, only a few have achieved high activity in both acid and alkaline electrolytes due to the inherent poor conductivity and low active sites. In this work, a heterojunction of cobalt sulfide and Mo 2 N is designed for efficient hydrogen evolution reactions in both acid and alkaline electrolytes. X-ray photoelectron spectroscopy reveals that Mo−S bonds are formed at the interface between Mo 2 N and CoS 2 , which result in the fabricated Mo 2 N/CoS 2 materials exhibiting a considerably enhanced hydrogen evolution reaction activity than the corresponding Mo 2 N, CoS 2 , and most reported Mo-and Co-based catalysts in electrolytes of H 2 SO 4 and KOH solutions. Density functional theory calculations suggest that the redistribution of charges occurs at the heterointerface. In addition, the interfacial active sites possess a considerably lower hydrogen adsorption Gibbs free energy than those atoms that are far away from the interface, which is beneficial to the process of hydrogen evolution reaction. This study provides a feasible strategy for designing hetero-based electrocatalysts with a tuned highly active interface.

Serpentine Ni3Ge2O5(OH)4 Nanosheets Grow on Porous Mo2N for an Efficient Oxygen Evolution Reaction

“…As the SEM image in Figure a exhibited, Mo 2 N is in the form of microscale particles with a size from 100 to 600 nm. The surface of these microparticles shows a porous structure with clean pore edges, which is identical to our previous reports . Moreover, the N 2 adsorption–desorption analysis was carried out to confirm the porous structure of Mo 2 N (Figure S1 of the Supporting Information).…”

“…The surface of these microparticles shows a porous structure with clean pore edges, which is identical to our previous reports. 28 Moreover, the N 2 adsorption−desorption analysis was carried out to confirm the porous structure of Mo 2 N (Figure S1 of the Supporting Information). The hysteresis loop of N 2 adsorption− desorption curves indicates the porous structure of the materials.…”

Laser synthesis of amorphous CoSxnanospheres for efficient hydrogen evolution and nitrogen reduction reactions

“…For driving a current density of 100 mA cm À2 , CoS x /CC-L and 20 wt% Pt/C required an overpotential of 229 mV and 150 mV, respectively. Through comparison with the other cobalt suldebased electrocatalysts, the HER activity of CoS x /CC-L with a low overpotential of 87 mV to achieve À10 mA cm À2 in 0.5 M H 2 SO 4 was better than or comparable to the leading cobalt suldebased HER catalysts, such as cobalt sulde/reduced graphene oxide/carbon nanotubes (CoS 2 /RGO-CNTs) (142 mV), 29 CoS 2 nanowires (145 mV), 30 Co 0.9 S 0.58 P 0.42 (139 mV), 31 surface selenized meso-CoS 2 (110 mV), 32 Co 9 S 8 @MoS x (98 mV), 33 Co 9 S 8 -NDCL (96 mV), 34 Mo 2 N/CoS 2 (85 mV), 35 Zn 0.30 Co 2.70 S 4 (80 mV), 36 CoS 2 @MoS 2 /RGO (98 mV), 37 Co 9 S 8 /MoS 2 (97 mV) 38 and Co 3 -S 4 @MoS 2 (210 mV) 39 (Table S2 †). For further studying the inuence of N-doping on the achieved HER activity of CoS x /CC- This journal is © The Royal Society of Chemistry 2022 L, we prepared control samples by laser processing Co-MOF/CC using the mixed gases of H 2 S and NH 3 with their different ratios (10% NH 3 /H 2 S, 20% NH 3 /H 2 S and 50% NH 3 /H 2 S), to obtain different N doped CoS x /CC-L samples (denoted as CoS x /CC-10% NH 3 -L, CoS x /CC-20% NH 3 -L and CoS x /CC-50% NH 3 -L).…”

Metal–organic framework (MOF)-derived plate-shaped CoS1.097 nanoparticles for an improved hydrogen evolution reaction

“…A lower R CT indicates faster electron diffusion between the used electrode surface and supporting electrolyte, thereby resulting in stronger HER activity. 49,50 The inset in Fig. 5d is the fitted equivalent circuit diagram obtained from the EIS result.…”