Engineering Water-Lotus-like Iridium–Cobalt Carbonate Hydroxides on Plasma-Treated Carbon Fibers for Enhanced Electrocatalytic Oxygen Evolution
Yingpeng Xie, Jinfeng Qiu, Guangliang Chen, Yingchun Guo, Peisong Tang, Bin He
Abstract
The sluggish kinetics of the oxygen evolution reaction (OER) in alkaline water electrolysis remains a significant challenge for developing high-efficiency electrocatalytic systems. In this study, we present a three-dimensional, micrometer-sized iridium oxide (IrO 2 ) - decorated cobalt carbonate hydroxide (IrO 2 -P-CoCH) electrocatalyst, which is engineered in situ on a carbon cloth (CC) substrate pretreated with atmospheric-pressure dielectric barrier discharge (DBD) plasma (PCC). The electrocatalyst features petal-like structures composed of nanosized rods, providing abundant reactive areas and sites, including the oxygen vacancy caused by the air–DBD plasma. As a result, the IrO 2 -P-CoCH/PCC electrocatalyst demonstrates an outstanding OER performance, with overpotentials of only 190 and 300 mV required to achieve current densities of 10 mA cm –2 ( j 10 ) and 300 mA cm –2 ( j 300 ), respectively, along with a low Tafel slope of 48.1 mV dec –1 in 1.0 M KOH. Remarkably, benefiting from rich active sites exposed on the IrO 2 -P-CoCH (Ir) heterostructure, the synergistic effect between IrO 2 and CoCH enhances the charge delivery rates, and the IrO 2 -P-CoCH/PCC exhibits a superior electrocatalytic activity at a high current density (300 mV/ j 300 ) compared to the commercial benchmarked RuO 2 /PCC (470 mV /j 300 ). Furthermore, the IrO 2 -P-CoCH/PCC electrocatalyst shows exceptional OER stability, with a mere 1.3% decrease with a current density of j 10 for 100 h testing, surpassing most OER catalysts based on CC substrates. This work introduces a novel approach for designing high-performance OER electrocatalysts on flexible electrode substrates.