In situ construction of Fe3O4@FeOOH for efficient electrocatalytic urea oxidation

Harshad A Bandal; Hern Kim

doi:10.1016/j.jcis.2022.07.104

In situ construction of Fe₃O₄@FeOOH for efficient electrocatalytic urea oxidation

J Colloid Interface Sci. 2022 Dec:627:1030-1038. doi: 10.1016/j.jcis.2022.07.104. Epub 2022 Jul 21.

Authors

Harshad A Bandal¹, Hern Kim²

Affiliations

¹ Department of Energy Science and Technology, Environmental Waste Recycle Institute, Myongji University, Yongin, Gyeonggi-do 17058, Republic of Korea.
² Department of Energy Science and Technology, Environmental Waste Recycle Institute, Myongji University, Yongin, Gyeonggi-do 17058, Republic of Korea. Electronic address: hernkim@mju.ac.kr.

PMID: 35907328
DOI: 10.1016/j.jcis.2022.07.104

Abstract

Substituting water oxidation half of water splitting with anodic oxidation of urea can reduce the cost of H₂ production and provide an avenue for treating urea-rich wastewater. However, developing an efficient and stable electrocatalyst is necessary to overcome the indolent kinetics of the urea oxidation reaction (UOR). Accordingly, we have used the Schikorr reaction to deposit Fe₃O₄ particles on the nickel foam (Fe₃O₄/NF). Results from the various analysis indicated that under the operational conditions, Fe₃O₄ underwent surface reconstruction to produce a heterolayered structure wherein a catalytically active FeOOH layer encased a conducting Fe₃O₄. Fe₃O₄/NF outperformed RuO₂ as a UOR catalyst and delivered a current density of 10 50 and 100 mA cm^-2 at low applied potentials of 1.38 1.42 and 1.46 V, respectively, with a Tafel slope of 28 mV dec^-1. At the applied potential of 1.4 V, Fe₃O₄/NF demonstrated a turnover frequency (TOF) of 2.8 × 10^-3 s^-1, highlighting its superior intrinsic activity. In addition, a symmetrical urea electrolyzer constructed using Fe₃O₄/NF produced the current density of 10 mA cm^-2 at a cell voltage of 1.54 V.

Keywords: Fe(3)O(4); H(2) generation; Surface reconstruction; Urea oxidation reaction.