Precious Metal-Free CoP Nanorod Electrocatalyst as an Effective Bifunctional Oxygen Electrode for Anion Exchange Membrane-Unitized Regenerative Fuel Cells

Abstract

In this study, noble metal-free Co(OH)F and CoP nanorod electrocatalysts were prepared and explored as bifunctional oxygen electrodes (BOE) in anion exchange membrane-unitized regenerative fuel cells (AEM-URFCs). A CoP nanorod was synthesized from Co(OH)F via the hydrothermal treatment of cobalt nitrate, ammonium fluoride, and urea, followed by phosphorization. The crystal structures, surface morphologies, pore distributions, and elemental statuses of the obtained catalysts were analyzed to identify the changes caused by the incorporation of fluorine and phosphorus. The presence of F and P was confirmed through EDS and XPS analyses, respectively. Using these catalysts, the AEM-based URFCs were operated with hydrogen and oxygen in the fuel cell mode and pure water in the electrolysis mode. In addition, the electrocatalytic activities of the catalysts were evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. In the AEM-URFC test, the CoP catalyst in the BOE delivered the best performance in the fuel cell mode (105 mA cm−2 at 0.3 V), and Co(OH)F was suitable for the water electrolyzer mode (30 mA cm−2 at 2.0 V). CoP and Co(OH)F exhibited higher round trip efficiency (RTE) and power densities than the conventional Co3O4 catalyst.

High-performance supercapacitors: electrochemical insights into CoP/MXene nanomaterial performance

“…Its abundance and potential cost-effectiveness make it a compelling choice for advancing energy storage technologies. 4 MXene materials shine in electrochemical performance with excellent conductivity, a large surface area for efficient reactions, and high mechanical strength. Their tunable properties and versatility make them a superior choice for supercapacitor applications, showcasing their potential to advance electrochemical technologies.…”

Anion-Exchange Membrane “Polikon A” Based on Polyester Fiber Fabric (Functionalized by Low-Temperature High-Frequency Plasma) with Oxidized Metal Nanoparticles

“…It is noted that the high conductivity of hydroxide and bicarbonate anions has been demonstrated in a number of formats in AEMs, while the internal stability of membrane polymers and the demonstration of a long service life in these devices remain questionable. Membrane material strategies, detailed structure-property analysis, and insights into materials’ performance and degradation have pushed the field into the mainstream of fuel cell and energy-related device research [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. However, most currently reported materials have not proven their usefulness in device stability tests lasting more than 1000 h [ 1 ].…”

“…The key component for the electrolysis of water with an AEM is a cheap, stable, gas-tight, and good hydroxide-conducting polymer AEM. Articles [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] present target values and specifications for AEMs, discuss chemical structures and associated degradation pathways, and review the most-known and promising commercial AEMs, as well as their properties and the characteristics of the water electrolyzers that use these membranes. The authors of [ 5 ] came to the conclusion that all materials (membrane, catalyst, cell design, etc.)…”