Heterostructure LDH/oxides as p-n type Electrocatalyst for the alkaline Water Splitting: An Experimental Assessment via Temperature-dependent Study

Abstract

Understanding reaction kinetics and catalytic mechanism plays a pivotal role in developing low-cost materials for water splitting reaction. Herein, a hierarchically structured MnFe-LDH/Mn2O3 heterostructure was fabricated on Ni foam using a facile simple hydrothermal synthesis route, which showed higher HER and OER performance in under alkaline media, where MnFe-LDH and Mn2O3 act as n- and p-type semiconducting materials, respectively. Furthermore, the heterostructure displays excellent selectivity by the faradaic efficiency as high as 93.31% at 1.61 V potential. In addition, the electrocatalysts exhibits performance for 36 h at 1.56 V signifies its sturdiness. The reaction kinetics was evaluated via temperature-dependent study, revealing enhanced OER kinetics for MnFe-LDH/Mn2O3 heterostructure as compared to bare MnFe-LDH and Mn2O3. The activation energy of heterostructure material (5.37 KJ/mol) is reduced to half than that of pristine Mn2O3 (10.7 KJ/mol) at the potential of 1.8 V, pH-dependent study confirms the MnFe-LDH/Mn2O3 heterostructure dominates reaction pathway via adsorbate enhancement mechanism (AEM) instead of the lattice oxygen mechanism (LOM). This work delivers an alternate approach to elucidate the reaction kinetics and catalytic mechanism for the development of an efficient bifunctional electrocatalyst toward water splitting applications.