Construction of Cobalt Molybdenum Diselenide Three‐phase Heterojunctions for Electrocatalytic Hydrogen Evolution in Acid Medium

Abstract

Molybdenum diselenide and cobalt diselenide have been commonly implemented in electrocatalytic hydrogen evolution reaction (HER). However, there have been few research on the creation of their three‐phase heterojunctions and the associated HER process. Herein, we constructed a three‐phase heterostructure sample consisting of orthorhombic CoSe2, cubic CoSe2 and MoSe2 and we investigated its HER performance. The sample shows microsphere morphology composed of nanosheets with interfacial interactions between the components. It possesses an overpotential of −136 mV at −10 mA cm−2 in acid medium, which is superior to that of single component and most two‐phase heterostructures. Especially, the overpotential at −200 mA cm−2 is smaller than that of Pt/C. The excellent performance can be attributed to the d‐orbital upshift of the Co active sites due to charge redistribution between the three‐phase heterojunction and the optimization of the hydrogen free energy. This work provides inspiration for exploring the application of other multi‐component heterojunctions in electrocatalytic hydrogen evolution.

Co3O4/CoS2 Heterostructure: Synergistic Interfacial Coupling Induced Superior Electrochemical Performance for Hydrazine Oxidation Reaction

“…In contrast, a sharp anodic response is noted at 0.25 V with 0.1 M N 2 H 4 . Further, a continual increase in the anodic current density with an increment in hydrazine concentration suggests that the Co 3 O 4 /CoS 2 heterostructure is catalytically active for the electro-oxidation of hydrazine. − A solution of 0.5 M N 2 H 4 and 1.0 M KOH was used as an electrolyte for all further experiments, since there was no significant change in the onset potential with a further increase in the hydrazine concentration.…”

“…Transition-metal-based compounds, such as oxides, nitrides, phosphides, and chalcogenides have emerged as efficient electrocatalytic materials for the HzOR and HER. − Among them, Co-based electrocatalysts are regarded as efficient electrode materials for the hydrazine oxidation reaction. In particular, the spinel cobalt oxide (Co 3 O 4 ) is very interesting due to its unique electronic state, multiple-oxidation-state-induced redox properties, excellent stability, and significant electrochemical activity toward hydrazine oxidation. − For example, Xu et al have fabricated Co 3 O 4 over a Co foam electrode for energy-efficient hydrazine-assisted hydrogen production .…”

Recent advances in molybdenum diselenide-based electrocatalysts: preparation and application in the hydrogen evolution reaction

“…118 Note that such an electrocatalyst can be employed as both cathode and anode for overall water splitting, which only needs 161 mV cell voltage at 10 mA cm −2 . Interestingly, three-phase oc-CoSe 2 /MoSe 2 microspheres without CC substrate indicated a considerable overpotential of 136 mV and a low Tafel slope of 47 mV dec −1 compared with that of o-CoSe 2 /c-CoSe 2 /MoSe 2 on CC, 119 lower than those of previous reported electrocatalysts MoSe 2 –CNT, 165 CoSe 2 /MoO 2 /MoSe 2 , 166 0.2CoSe 2 /MoSe 2 , 167 MoSe 2 –CoSe 2 NTs, 168 MoSe 2 /CoSe 2 microcage, 169 CoSe 2 –MoSe 2 /rGO–C, 170 CoSe 2 @MoSe 2 nanocubes, 171 MoSe 2 /CoSe hollow spheres, 172 H-NiSe 2 /MoSe 2 , 173 CoSe/MoSe 2 , 174 and o-CoSe 2 /c-CoSe 2 /MoSe 2 /CC, 118 higher than those of 3Co–MoSe 2 –GNS@CNT 127 and MoSe 2 /CoSe 2 hybrid. 175 Moreover, CC/MOF-CoSe 2 @MoSe 2 catalyst can be used in alkaline HER and showed an excellent catalytic activity with an overpotential of 109.87 mV and a Tafel slope of 68.91 mV dec −1 , much better that those of MoSe 2 –CoSe 2 NTs/G (198 mV vs. RHE, 79 mV dec −1 ), 176 CC/MOF (186.13 mV, 172.16 mV dec −1 ), CC/MoSe 2 (130.88 mV, 131.99 mV dec −1 ), 128 and the previously reported MoSe 2 /CoSe 2 @CFP (137 mV, 55.9 mV dec −1 ).…”

“…14e and f). 119 The solvothermal synthesis of Na 2 MoO 4 •2H 2 O, Se, N 2 H 4 •H 2 O, and biomass in a mixed solution of water and N,N-dimethylformamide (DMF) at 200 °C for 3 h generated biomass-loaded MoSe 2 . After incipient wetness impregnation of RuCl 3 , the obtained RuCl 3 -impregnated biomass-loaded MoSe 2 was carbonated at 500 °C to afford Ru-MoSe 2 on carbon microtube (Ru-MoSe 2 /CMT) (Fig.…”

Charge Redistribution of Co9S8/MoS2 Heterojunction Microsphere Enhances Electrocatalytic Hydrogen Evolution

“…The first three of these require unsustainable sources of raw materials. Hydrogen production from electrolytic water splitting has gained worldwide attention because of its environmental friendliness, production flexibility, and product purity [ 5 , 6 , 7 ]. Efficient electrolytic hydrogen production from water requires effective electrocatalysts to reduce the energy consumption of the hydrogen evolution reaction (HER).…”