Tip-Enhanced Electric Field : A New Mechanism Promoting Mass Transfer in Oxygen Evolution Reactions

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Peng Liu
  • Bo Chen
  • Caiwu Liang
  • Wentao Yao
  • Yuanzheng Cui
  • Shengyu Hu
  • Peichao Zou
  • Hong Jin Fan
  • Cheng Yang

Related Research Unit(s)

Detail(s)

Original languageEnglish
Article number2007377
Journal / PublicationAdvanced Materials
Volume33
Issue number9
Online published29 Jan 2021
Publication statusPublished - 4 Mar 2021

Abstract

The slow kinetics of oxygen evolution reaction (OER) causes high power consumption for electrochemical water splitting. Various strategies have been attempted to accelerate the OER rate, but there are few studies on regulating the transport of reactants especially under large current densities when the mass transfer factor dominates the evolution reactions. Herein, NixFe1–x alloy nanocones arrays (with ≈2 nm surface NiO/NiFe(OH)2 layer) are adopted to boost the transport of reactants. Finite element analysis suggests that the high-curvature tips can enhance the local electric field, which induces an order of magnitude higher concentration of hydroxide ions (OH) at the active sites and promotes intrinsic OER activity by 67% at 1.5 V. Experimental results show that a fabricated NiFe nanocone array electrode, with optimized alloy composition, has a small overpotential of 190 mV at 10 mA cm−2 and 255 mV at 500 mA cm−2. When calibrated by electrochemical surface area, the nanocones electrode outperforms the state-of-the-art OER electrocatalysts. The positive effect of the tip-enhanced local electric field in promoting mass transfer is also confirmed by comparing samples with different tip curvature radii. It is suggested that this local field enhanced OER kinetics is a generic effect to other OER catalysts.

Research Area(s)

  • electrochemical water splitting, local electric enhancement, mass transport, oxygen evolution reaction, tip-enhanced aggregation

Citation Format(s)

Tip-Enhanced Electric Field: A New Mechanism Promoting Mass Transfer in Oxygen Evolution Reactions. / Liu, Peng; Chen, Bo; Liang, Caiwu et al.
In: Advanced Materials, Vol. 33, No. 9, 2007377, 04.03.2021.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review