(6bx) Nife Layered Double Hydroxide/Hollow Prussian Blue Via Alkaline Etching As an Efficient Electrocatalyst for Oxygen Evolution Reaction

Teaching Interests: electrochemical catalysis

Oxygen evolution reaction (OER) is an imperative electrode reaction in many electrochemical applications, such as metal-air batteries, fuel cells and electrochemical water splitting. Much effort has been made to overcome its sluggish kinetics and decrease the overpotential. Recently, NiFe layered double hydroxide (NiFe-LDH) has been reported frequently as a new benchmarking OER electrocatalyst, even surpassing the activity of noble metal electrocatalysts such as Ir and Ru-based electrocatalysts [1]. In order to make further progress, creating NiFe-LDH with novel 3D morphologies is becoming a topical strategy [2].

Recently, we successfully synthesized a NiFe-LDH in-situ grown on hollow Prussian blue (PB) via alkaline etching as an efficient OER electrocatalyst. In this presentation, we will show a hollow-structured electrocatalyst denoted as LDH/PB-pH11-50 ^oC. It has an incompletely etched hollow PB as the inner framework and an in-situ grown NiFe-LDH as the main catalytic surface layer. When applied as OER electrocatalyst, it shows a low overpotential of ~242 mV to drive a current density of 10 mA cm^-2 in 1 M KOH. This result is obviously superior to that of pure NiFe-LDH (~257 mV) and pure PB (~334 mV) synthesized by the similar method. The highlights of this work are shown below. Firstly, because the NiFe-LDH is synthesized from PB via a weakly alkaline etching, the residual PB may improve the performance of NiFe-LDH in the alkaline electrolyte. Besides, the hollow structure of residual PB is beneficial to the mass transfer and the enlargement of specific surface area, which can further enhance the catalytic activity of the electrocatalyst. Secondly, the main OER active component NiFe-LDH can be synthesized and in-situ imbedded onto the hollow PB framework simultaneously via the alkaline etching. This strategy significantly simplifies the synthesis of the material. In order to optimize the performance of the as-prepared electrocatalyst, the influences of pH and temperature towards structure-electrocatalytic activity relationship will be investigated in detail in the following work.

Reference

[1] Dionigi F and Strasser P. NiFe-Based (Oxy)hydroxide Catalysts for Oxygen Evolution Reaction in Non-Acidic Electrolytes. Advanced Energy Materials 1600621, 1-20 (2016).

[2] Xiaowen Y U, Zhang M, Yuan W and Shi G. High-performance three-dimensional Ni-Fe layered double hydroxide/graphene electrode for water oxidation. Journal of Materials Chemistry A 3, 6921-6928 (2015).