Abstract
Green hydrogen is becoming a hot commodity in the light of escalating oil and gas prices and their uncertain future availability. Among various electrolysis technologies, PEM water electrolysis (WE) is favorable for its portability, modularity, and the ability to integrate with intermittent, renewable energy sources. However, the upscaling of PEMWE is not feasible yet due to the need for rare and expensive metals as electrocatalysts. Specifically, iridium oxide is used as state-of-the art anodic electrocatalyst. Ruthenium oxide also has an excellent activity towards the anodic oxygen evolution reaction (OER), but is highly unstable. To address this limitation, this study investigates ruthenate pyrochlores as alternative anodic electrocatalysts. The pyrochlore structure may stabilize ruthenium. The pyrochlores in this study have been synthesized using a traditional citrate sol-gel method,1 as well as a novel combustion synthesis route. Physical characterization of the electrocatalysts has been conducted using x-ray diffraction (XRD), scanning (transmission) electron spectroscopy (S(T)EM) and Raman spectroscopy. Additionally, ex-situ electrochemical characterization has been performed in a three-electrode setup. Linear-sweep voltammetry results of Y2Ru2O7 synthesised via the citrate sol-gel route indicate an overpotential of 300 mV at a current density of 10 mA cm-2. This result agrees well with what has previously been reported for this electrocatalyst.2 Y2Ru2O7 synthesised via the novel combustion route performs better than the aforementioned due to increased surface area. Various A-site dopants have also been introduced into the pyrochlore structure to generate oxygen vacancies, modify the electronic structure and increase the stability. These materials have also been tested in a full-cell setup to gauge their performance for practical applications compared to state-of-the-art IrO2 and RuO2. References (1) Kim, J.; Shih, P.-C.; Tsao, K.-C.; Pan, Y.-T.; Yin, X.; Sun, C.-J.; Yang, H. High-Performance Pyrochlore-Type Yttrium Ruthenate Electrocatalyst for Oxygen Evolution Reaction in Acidic Media. J. Am. Chem. Soc. 2017, 139 (34), 12076–12083.(2) Feng, Q.; Zou, J.; Wang, Y.; Zhao, Z.; Williams, M. C.; Li, H.; Wang, H. Influence of Surface Oxygen Vacancies and Ruthenium Valence State on the Catalysis of Pyrochlore Oxides. ACS Appl. Mater. Interfaces 2020, 12 (4), 4520–4530.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call