Optimized Metal Chalcogenides for Boosting Water Splitting

Abstract

splitting (2H 2 O → 2H 2 + O 2 ), consisting of hydrogen evolution and oxygen evolution reaction (HER/OER), can convert electricity to chemical energy in H 2 and O 2 for further energy applications. The practical application of overall water splitting, however, is still limited due to the lack of effective and stable catalysts to reduce reaction energy barrier and enhance Faraday efficient for both reactions. [6][7][8][9][10] Different materials have been studied for overall water splitting catalysis, like metal chalcogenides, metal carbides, oxides, etc. The transition metal carbides, especially graphene, have a better electroconductivity, ductility, and high surface area which display excellent performance in water splitting. [11][12][13] Oxides as another abundant species on the earth also show better water splitting performance, but their stability in hard media is not very good. [14][15][16] The layered double hydroxides (LDH) with unique structure, abundant interstratified electrons and channels for intermediate adsorption and desorption display wonderful water splitting performance. [17][18][19][20] Additionally, the metalorganic frameworks (MOFs) and their based nanocrystals as newly nanomaterials have got much attention in various fields, but their structure limited the active sites exposure for the complete coordinative metal sites. [21][22][23][24][25] Therefore, it is important to enable the cost-effective, large-scale production of these catalysts, and further improve the performance and efficiency of overall water splitting.Transition metal chalcogenides have many different compositions with various lattice structure, while those materials also have unique electronic structures. [26] Based on those superior properties, the transition metal chalcogenides show promising application in many energy applications, [27] such as electrochemical catalysis, photocatalysis, metal-air batteries, and other energy conversion reactions. Especially for their abundant defects sties, [26][27][28] tunable electronic structure, [29][30][31][32] and various morphology, [33][34][35][36][37] the transition metal chalcogenides exhibit boosting performance for water splitting. However, they still have some disadvantages, such as poor conductivity, activity, and stability, in water splitting limited their large-scale industrial application. [38][39][40][41][42] How to synthesize the active and stable transition metal chalcogenides is still a big challenge for wide application. In this Review, the several promising strategies are designed to prepare the active and stable transition metal chalcogenides (Scheme 1). → 2H 2 + O 2 ) is a very promising avenue to effectively and environmentally friendly produce highly pure hydrogen (H 2 ) and oxygen (O 2 ) at a large scale. Different materials have been developed to enhance the efficiency for water splitting. Among them, chalcogenides with unique atomic arrangement and high electronic transport show interesting catalytic properties in various electrochemical reactions, such as the ...

Recent Development of Oxygen Evolution Electrocatalysts in Acidic Environment

“…[55,65,95] Despite the initial crystalline structure, it has been found that many catalysts go through surface reconstruction to form an amorphous structure, which is identified as the active site. [29,30] Different from the long-range order and translational symmetry for crystalline structure, the atoms arrangement in the amorphous structure is in disorder and thus provides some unique properties: 1) The inherent disorder can produce abundant irregular oriented bonds and defects as active sites to improve catalytic activity; [35,96] 2) The chemical fluctuations, local topology, and isotropic properties enable amorphous materials possess unique characteristics, i.e., elastic strain, magnetic properties, and corrosion resistance; [79,97] For example, Li and co-workers have successfully prepared a series of monometallic amorphous nanosheets (Ir NSs, Rh NSs, and Ru NSs), bimetal amorphous nanosheets (RhNi NSs, RhCo NSs, RhRu NSs, IrFe NSs, IrNi NSs, and IrCo NSs), and even trimetallic amorphous nanosheets (IrRhRu NSs) for improving the performance of OER in acidic environment. [97] A recent study has investigated the difference between the OER at amorphous structure and crystalline structure with RuTe 2 porous nanorods as model catalysts (Figure 6).…”

“…Lattice strain caused by lattice vacancies, lattice distortion, or lattice mismatch can tune the electronic structure. [79] Lattice strain includes tensile strain and compressive strain, which, for example, under an octahedral coordination, favor the filling of in-plane (d x y 2 2…”

Efficient electrochemical water splitting using copper molybdenum sulfide anchored Ni foam as a high-performance bifunctional catalyst

“…15 Currently, transition metal-based chalcogenides, phosphides, oxides, and their derivatives are examined as bifunctional catalysts in an alkaline medium. 2,[16][17][18][19][20][21] However, these materials are still needed to be engineered to reduce the overpotentials in both anode and cathode during the electrochemical water splitting reactions. 22 It is expected that multicomponent transition metal-based catalysts can be an ideal candidate for electrocatalytic reactions due to their high redox states and improved conductivity over their single component ones.…”

Designing MOF Nanoarchitectures for Electrochemical Water Splitting

“…[1,2] In this context, electrochemical water splitting, which converts electricity into storable hydrogen, is a viable and efficient solution to mitigate severe energy shortages and greenhouse gas emissions. [3] Among these strategies, hydrogen and oxygen evolution reactions, which occur on the cathode and anode, respectively, in a water electrolyzer, are considered as two critical half-reactions of the water-splitting process. [4] Theoretically, water splitting requires a thermodynamic Gibbs free energy (ΔG) of approximately 237.2 kJ mol −1 , corresponding to a standard potential (ΔE) of 1.23 V versus a reversible hydrogen electrode (RHE), which allows the thermodynamically uphill reaction to occur in the electrolyzer.…”