In-situ activation of self-supported 3D hierarchically porous Ni3S2 films grown on nanoporous copper as excellent pH-universal electrocatalysts for hydrogen evolution reaction

Abstract

The exploitation of low-cost, stable, and highly active electrocatalysts based on earth-abundant metals for hydrogen evolution reaction (HER) is crucial for developing renewable energy techniques. In this work, we report a facile synthesis strategy for in-situ fabrication of 3D hierarchically porous Ni3S2 films on a nanoporous copper substrate (Ni3S2@NPC) by unusual galvanic replacement reaction in the Ethaline-based deep eutectic solvent (DES) under a normal atmosphere. The self-supported nanoporous Ni3S2@NPC electrode is binder-free and exhibits good structural integrity with high conductivity. A mild evolution of bulk gas bubbles (H2-O2 gas mixture) is proved to drive an in-situ structure rearrangement process of the Ni3S2@NPC and results in substantial increases in the HER activity. The activated Ni3S2@NPC (a-Ni3S2@NPC) electrode can serve as a highly efficient and stable electrocatalyst for the HER in water over a wide pH range. Significantly, it displays high-performance HER catalytic activity in acidic media with robust durability over 111 h and functions well under alkaline and neutral conditions. Such a superior catalytic performance of the a-Ni3S2@NPC is mainly due to the unique hierarchically nanoporous architectures and the synergetic effects in it caused by the restructuring NPC skeletons and active components. Our work offers a generic strategy for design and fabrication of many other self-supported transition metal sulfide and phosphide based HER electrocatalysts, and uncovers a new O2-induced electrochemical self-activation mechanism for improving the activity of catalysts.

Flexible Honeycombed Nanoporous/Glassy Hybrid for Efficient Electrocatalytic Hydrogen Generation

“…[12][13][14][15][16][17] The uniform bicontinuous nanoporosity produced by dealloying/etching can offer nanoporous materials satisfactory electrocatalytic activities, high-efficiency electron transportation, and improved selectivity for various redox reactions. [12][13][14][15][16][17] The uniform bicontinuous nanoporosity produced by dealloying/etching can offer nanoporous materials satisfactory electrocatalytic activities, high-efficiency electron transportation, and improved selectivity for various redox reactions.…”

An Intriguing Pea‐Like Nanostructure of Cobalt Phosphide on Molybdenum Carbide Incorporated Nitrogen‐Doped Carbon Nanosheets for Efficient Electrochemical Water Splitting

“…[56][57][58] In particular, TOF values for Co-Mo 2 C@NC/CC and CoP-Mo 2 C@NC/CCa re 0.27 and 0.71 s À1 ,r espectively,a taHER over-potentialof1 00 mV.Similarly,ahigherTOF value was observed for phosphide material (1.22 s À1 )t han that of Co-Mo 2 C@NC/CC (0.67 s À1 )a ta nO ER overpotential of 350 mV;t hus confirming CoP-Mo 2 C@NC/CC as an intrinsically better bifunctional electrocatalyst than those of the other materials (Figures S13 and S14 and Ta ble S5 in the Supporting Information). [59,60] The developedm aterial works well as an HER catalyst, with an overpotential (h 10 )o fo nly 107 mV and al ow Tafel slope of 70.8 mV dec À1 ;t hese values are identicalt ot hose obtainedi n an alkaline medium (Figure 5a). [59] The bifunctionality of CoP-Mo 2 C@NC/CC was further tested in acid electrolyte (0.5 m H 2 SO 4 )t od emonstrate its applicability over wide pH ranges for electrochemical water splitting.…”

Recent Progresses in Electrocatalysts for Water Electrolysis

“…These chalcogenides include NiS 2 , 3D Ni 3 S 2 , NiS-MoS 2 , Ni-Co-MoS, V-doped NiS, NiSe, NiSe@CoP, Ni-W-S and Ni-S-CeO 2 [271][272][273][274][275][276][277][278]. Among these chalcogenides, Ni sulphides are important because they are highly abundant and possess high intrinsic activities and good electrical transport abilities.…”

“…Among these chalcogenides, Ni sulphides are important because they are highly abundant and possess high intrinsic activities and good electrical transport abilities. In one example, Yang et al [272] fabricated a 3D Ni 3 S 2 nanofilm on a nanoporous copper substrate (Ni 3 S 2 @NPC) and the resulting catalyst demonstrated high catalytic activities in both acidic and alkaline media, with an overpotential value of 91.6 and 60.8 mV, respectively. The researchers conducted DFT studies to illustrate the electronic structure and relative density states of the rhombohedral crystal planes, and here, XRD patterns of the template were used as a reference and highlighted the characteristic peaks of the rhombohedral crystal plane.…”

“…Based on this, Shang et al [274] obtained vanadium (V)-doped NiS nanowires supported on Ni foam through in situ cathodic activation (ISCA) in which the formation of nanowires enlarged active surface areas, exposed more sites and allowed for faster electrolyte diffusions to the active surfaces [272]. f Schematic representation of the in situ cathodic activation (ISCA) of the VS/Ni x S y /NF.…”