Universal Strategy of Bimetal Heterostructures as Superior Bifunctional Catalysts for Electrochemical Water Splitting

Abstract

Utilizing earth-abundant metals to design economical and efficient electrocatalysts for cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) is critical for acquiring clean hydrogen energy by the electrochemical overall water-splitting system. In this work, we reported a facile and universal strategy toward developing a suite of bimetallic heterostructures, representing as highly efficient catalysts of the HER/OER process. By hybridizing transition-metal sulfides (CoS 2 , NiS 2 , FeS 2 , and CuS) with highly active MoS 2 nanosheets, all heterostructural catalysts achieved largely improved bifunctional activity originating from the special interfacial interaction as well as synergetic catalytic effects. As a result, the optimal CoS 2 @MoS 2 /CC and NiS 2 @MoS 2 /CC heterostructures displayed the lowest overpotentials at 10 mA cm −2 , which only required 31 and 225 mV for HER/OER, respectively. After assembling for water splitting, the electrolyzer exhibited a very small cell voltage of 1.58 V to reach 10 mA cm −2 . This result is obviously better than a lot of reported non-precious metal catalysts. Our strategy experimentally confirms the feasibility of the heterostructure to enhance the bifunctional performance of advanced electrocatalysts for electrochemical water splitting.

Iodide Oxidation Reaction Catalyzed by Ruthenium–Tin Surface Alloy Oxide for Efficient Production of Hydrogen and Iodine Simultaneously

“…To date, fossil fuel chemistry has played a significant role in energy conversion and storage devices; however, the scarcity and emission of CO 2 as a byproduct restrict its feasibility as future energy resources. − Recently, hydrogen (H 2 ), as a carbon-free clean energy carrier, has attracted an alternative option to alleviate the energy demand for a global society. − Currently, the electrolysis of water plays a prominent role as a front-running technology for hydrogen fuel production. − However, the high overpotentials required due to sluggish anodic oxygen evolution (OER) and cathodic hydrogen evolution (HER) result in low energy conversion efficiency. − Although the minimum theoretical voltage consumption for traditional water electrolysis is only 1.23 V, commercial electrolyzers usually work at voltages higher than 1.8 V. , Besides, water electrolysis generates O 2 and H 2 simultaneously, , which facilitates the formation of reactive oxygen species (ROS), causing highly unsafe explosion risk and undoubtedly destructing the membrane by reducing the lifespan of the electrolyzer. ,− …”

Dual Vacancies Confined in Nickel Phosphosulfide Nanosheets Enabling Robust Overall Water Splitting

“…The rational design of high‐efficient electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of great importance for confronting the depletion of fossil resources and realizing a sustainable hydrogen economy [1–3] . High‐active electrocatalysts with low overpotential and high conversion efficiency for water splitting are the core goal and tremendous research efforts have been devoted [4–6] .…”

Single‐Step Solid‐State Scalable Transformation of Ni‐Based Substrates to High‐Oxidation State Nickel Sulfide Nanoplate Arrays as Exceptional Bifunctional Electrocatalyst for Overall Water Splitting

“…An impressively low cell potential of 1.46 V at 10 mA cm −2 and 1.69 at 100 mA cm −2 , which is indeed noteworthy (CV curve is presented in Figure S18, Supporting Information). To the best of our knowledge, the NIS-450(foam)||NIS-450(foam) electrocatalyst system exhibits the lowest overpotential values reported for the transition metal-based sulfides as a bifunctional electrocatalyst for overall water splitting [16,20,21,23,24,[26][27][28][29][30][31][32][33][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54] (Figure 5d). As expected, NIS-450(foam) shows two orders of magnitude higher C dl in comparison to the bare Ni foam (Figure S19, Supporting Information).…”