A Robust Nonprecious CuFe Composite as a Highly Efficient Bifunctional Catalyst for Overall Electrochemical Water Splitting

Abstract

As an energy source, hydrogen has outstanding properties, such as zero carbon emission, high conversion efficiency, and recyclability. [1] Moreover, it is the cleanest primary energy resource on earth and is a candidate for replacing fossil fuels. Water, which is the most abundant source of hydrogen, can be used for producing hydrogen if the strong bond between hydrogen and oxygen can be broken. Water electrolysis is a process in To generate hydrogen, which is a clean energy carrier, a combination of electrolysis and renewable energy sources is desirable. In particular, for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in electrolysis, it is necessary to develop nonprecious, efficient, and durable catalysts. A robust nonprecious copper-iron (CuFe) bimetallic composite is reported that can be used as a highly efficient bifunctional catalyst for overall water splitting in an alkaline medium. The catalyst exhibits outstanding OER and HER activity, and very low OER and HER overpotentials (218 and 158 mV, respectively) are necessary to attain a current density of 10 mA cm −2 . When used in a two-electrode water electrolyzer system for overall water splitting, it not only achieves high durability (even at a very high current density of 100 mA cm −2 ) but also reduces the potential required to split water into oxygen and hydrogen at 10 mA cm −2 to 1.64 V for 100 h of continuous operation.which water is split into oxygen and hydrogen, and technologies related to this process are attracting considerable attention for their potential use in the production of clean and environmentally friendly energy. [2] Electrochemical water splitting comprises two reactions: the hydrogen evolution reaction (HER) at the cathode and the oxygen evolution reaction (OER) at the anode. [1] Of these, the OER is the main reaction because it involves complex electron-proton transfer that leads to sluggish kinetics and a high overpotential.In general, all electrocatalysts used for splitting water into oxygen and hydrogen require a high overpotential in addition to the ideal potential (note that the total reaction ideally requires a potential difference of 1.23 V to split water into oxygen and hydrogen). A major challenge is the fabrication of durable and efficient catalyst materials for the OER. [3] In addition, from the viewpoint of productivity and cost effectiveness, it is highly advantageous to fabricate bifunctional electrocatalysts that operate efficiently for both the OER and HER in the same aqueous alkaline or acidic media. [4] Recently, oxides, carbides, sulphides, phosphides, and layered double hydroxides (LDHs) of transition metals, as well as mixed-metal alloys, have been extensively investigated for use as electrocatalysts for the OER and HER. [5][6][7][8][9][10][11][12][13][14][15][16] Furthermore, several strategies have been employed to improve the electrocatalytic performance of current catalyst materials: morphology engineering, hybrid composite synthesis doping, etc. [5][6][7][8][9][10][11][12][1...

In Situ Reconstruction of V‐Doped Ni2P Pre‐Catalysts with Tunable Electronic Structures for Water Oxidation

“…where C s is the specific capacitance of the electrode with a value of 0.04 mF cm −2 in an alkaline medium. [33] Rotating ring-disk electrode (RRDE) measurement was employed to evaluate the Faradaic efficiency.…”

Template‐free synthesis of one‐dimensional cobalt sulfide nanorod array as an attractive architecture for overall water splitting

“…Here, Cs of 0.040 mF cm −2 in 1.0 M KOH is used. 10,56 Figure S4A,B shows the cyclic voltametry of catalysts and corresponding C dl value ( Figure S4C) of the 1D-CoS (t ex 24h) film is 54 μF/cm 2 , which is much larger than that of the 1D-Co 3 O 4 (19 μF/cm 2 ), suggesting that the ion-exchange transformed nanorod array has increased surface area. Since electrochemical stability is another important parameter for an electrocatalyst.…”

Nonprecious bimetallic NiFe ‐layered hydroxide nanosheets as a catalyst for highly efficient electrochemical water splitting

“…Thus, climate change caused by pollution from utilizing fossil fuels has encouraged researchers to focus on energy conversion, storage, and supply issues 1 . Hydrogen is a very important candidate for replacing non‐renewable fossil fuels due to its outstanding properties such as high energy density, zero carbon emission, good recyclability, and high conversion efficiency 2,3 . It can be produced using environmentally friendly electrochemical water splitting or electrocatalysis consisting of two electrochemical processes 4‐7 : the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER).…”

“…Water electrolysis is the process by which the strong covalent bond between oxygen and hydrogen in H 2 O is broken, thereby producing oxygen and hydrogen molecules. However, the water‐splitting process is mainly determined by the OER due to its high overpotential, sluggish kinetics, and complex electron‐proton transfer 2 . Until now, noble metals and their oxides such as Pt, ruthenium (IV) oxide (RuO 2 ), and iridium (IV) oxide (IrO 2 ) have been exploited as catalyst electrodes due to their high efficiency and electrochemical stability.…”