New insights into interface charge-transfer mechanism of copper-iron layered double hydroxide cathodic electrocatalyst in alkaline electrolysis

Bhavanari, M and Lee, KR and Tseng, CJ and Su, BJ and Chen, JM and Chang, JK and Bhattacharyya, AJ and Su, CY (2022) New insights into interface charge-transfer mechanism of copper-iron layered double hydroxide cathodic electrocatalyst in alkaline electrolysis. In: Journal of Environmental Chemical Engineering, 10 (2).

PDF jou_env_che_eng_2022.pdf - Published Version Restricted to Registered users only Download (4MB) | Request a copy

Abstract

Transition metal layered hydroxides are potential catalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction in alkaline electrolysis (AE). Recent researches focused on NiFe layered double hydroxide (LDH) as efficient, cost-effective electrocatalyst due to the proton and hydroxide adsorption kinetics by Ni and Fe. However, Cu has been known to exhibit higher adsorption of the proton, thus by replacing Ni with Cu in NiFe LDH shows potential for enhancing the chemical kinetics of HER due to filled d-orbitals and electron transfer. Here, we first demonstrate a strategy of modulating the electronic structure of CuFe LDH, by manipulating Cu/Fe ratio and nanostructure, to improve the HER catalysis of single layer and cost-effective transition metal LDHs in AE. The atomic allocations of Cu and Fe based on the proposed method in the synthesis of LDH allows for optimizing the proton and hydroxide adsorption during electrocatalysis, where the CuFe LDH generate a current density of � 10 mA cm-2 at the overpotential of � 110 mV and a highly enhanced electrolysis stability at � 100 mA cm-2. Meanwhile, a low overpotential of 257 mV (10 mA cm-2) is achieved. Advanced spectroscopic characterizations, including X-ray photoelectron spectroscopy, confirms the electronic structure modulation with adjustment of Cu/Fe ratio; and the synchrotron sourced X-ray absorption spectroscopy unambiguously confirm the higher electron density of Cu and the unique M-O(H)-M� structure that enhances water splitting by facilitating ion adsorption and electron transfer. The cathodic activation energy of 14.34 kJ mol-1 is achieved by higher electronic density due to electronic modulation of the catalyst structure. This work demonstrates the insights of electronic structure modulation for the rational design of efficient catalysts without noble or rare-earth metals for HER. © 2022 Elsevier Ltd

Item Type:	Journal Article
Publication:	Journal of Environmental Chemical Engineering
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to Elsevier Ltd
Keywords:	Activation energy; Adsorption; Alkalinity; Binary alloys; Charge transfer; Copper alloys; Copper compounds; Cost effectiveness; Electrocatalysts; Electrolysis; Electronic structure; Hydrogen; Iron; Iron alloys; Iron compounds; Modulation; Orbits; Rare earths; Reusability; X ray photoelectron spectroscopy, Alkaline electrocatalyst; Alkaline electrolysis; Alkalines; Cost effective; Cufe layered double hydroxide; Electron transfer; Electronic.structure; Hydrogen evolution reactions; Layered-double hydroxides; Water splitting, Electrocatalysis
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	17 Feb 2022 06:38
Last Modified:	17 Feb 2022 06:38
URI:	http://eprints.iisc.ac.in/id/eprint/71312

Actions (login required)

View Item