Interface Engineering of MoS₂/Ni₃S₂ Heterostructures for Highly Enhanced Electrochemical Overall‐Water‐Splitting Activity

Abstract

To achieve sustainable production of H2 fuel through water splitting, low-cost electrocatalysts for the hydrogen-evolution reaction (HER) and the oxygen-evolution reaction (OER) are required to replace Pt and IrO2 catalysts. Herein, for the first time, we present the interface engineering of novel MoS2 /Ni3 S2 heterostructures, in which abundant interfaces are formed. For OER, such MoS2 /Ni3 S2 heterostructures show an extremely low overpotential of ca. 218 mV at 10 mA cm(-2) , which is superior to that of the state-of-the-art OER electrocatalysts. Using MoS2 /Ni3 S2 heterostructures as bifunctional electrocatalysts, an alkali electrolyzer delivers a current density of 10 mA cm(-2) at a very low cell voltage of ca. 1.56 V. In combination with DFT calculations, this study demonstrates that the constructed interfaces synergistically favor the chemisorption of hydrogen and oxygen-containing intermediates, thus accelerating the overall electrochemical water splitting.

Engineering Pyrite-Type Bimetallic Ni-Doped CoS2 Nanoneedle Arrays over a Wide Compositional Range for Enhanced Oxygen and Hydrogen Electrocatalysis with Flexible Property

“…The fitted Tafel slope of the Ni0.33Co0.67S2 (76 mV dec −1 ) was lower than those of Ni0.5Co0.5S2 (82 mV dec −1 ), Ni0.67Co0.33S2 (89 mV dec −1 ) and CoS2 (98 mV dec −1 ) counterparts, respectively. These Tafel values of NixCo1−xS2 suggest that the HER proceeds the Volmer-Heyrovsky mechanism [38]. Moreover, the Tafel values are consistent with the HER performance trend, which further reveals that the HER kinetics follow an order of Ni0.33Co0.67S2 > Ni0.5Co0.5S2 > Ni0.67Co0.33S2 > CoS2.…”

Utilizing the Space‐Charge Region of the FeNi‐LDH/CoP p‐n Junction to Promote Performance in Oxygen Evolution Electrocatalysis

“…As ac onsequence,t he positively charged FeNi-LDH side in the FeNi-LDH/CoP as ap -n junction would have greater ability to adsorb targeted OH À ,w hich serves as the decisive step for OER activity [49] according to the OER in alkaline conditions of 4OH À !2H 2 O(l) + O 2 (g) + 4e À , [50] than that of pure FeNi-LDH and CoP.F or supporting this point, LSV curves toward OER in the KOHe lectrolyte with different concentrations are conducted shown in Figure 7a-c and the corresponding potential differences at the same j shown in the Supporting Information, Table S4. As ac onsequence,t he positively charged FeNi-LDH side in the FeNi-LDH/CoP as ap -n junction would have greater ability to adsorb targeted OH À ,w hich serves as the decisive step for OER activity [49] according to the OER in alkaline conditions of 4OH À !2H 2 O(l) + O 2 (g) + 4e À , [50] than that of pure FeNi-LDH and CoP.F or supporting this point, LSV curves toward OER in the KOHe lectrolyte with different concentrations are conducted shown in Figure 7a-c and the corresponding potential differences at the same j shown in the Supporting Information, Table S4.…”

In Situ Grown Bimetallic MOF‐Based Composite as Highly Efficient Bifunctional Electrocatalyst for Overall Water Splitting with Ultrastability at High Current Densities

“…The OER performances of the present NFN-MOF/NF electrode are compared with those of recently reported stateof-the-art NF-based OER electrocatalysts [28,[42][43][44][46][47][48][49][50][51][52][53][54][55][56][57] in terms of catalyst loading on NF, η 10 , η at higher current densities if available, Tafel slope, and stability in Table S1 (Supporting Information). Evidently, the present NFN-MOF/NF electrode competes favorably.…”