Green hydrogen production via water electrolysis is expected to become an environmentally friendly technology for decentralized and seasonal energy storage provided that the hydrogen production cost becomes competitive. An ideal catalyst for the oxygen evolution reaction (OER), the sluggish process in water electrolysis, should operate at low overpotential, exhibit long-term stability, and utilize low-cost materials. High-surface-area metal oxide/(oxy)hydroxide nanostructures have demonstrated promising characteristics as low-cost OER catalysts. These non-noble metal-based, high-surface-area catalysts, however, usually do not possess long-term stability in acidic or alkaline electrolytes, especially at high operating potentials which are required for practical applications. The causes of catalyst degradation may originate from either chemical/electrochemical processes or both. For example, cobalt oxide/(oxy)hydroxide nanostructures, extensively studied as a promising OER catalyst, are not stable in acidic or alkaline media for long-term operations. Simultaneous stabilization of high-surface-area Co3O4 and improvement in its electrocatalytic performance are highly desirable. We report here the use of atomically dispersed Bi atoms to not only stabilize 2D-Co3O4 nanosheets but also significantly improve their activity for OER in alkaline electrolyte. Our Bi/2D-Co3O4 catalyst possesses an OER activity ~250 times that of the commercial Co3O4 catalyst and much superior performance to the commercial IrO2 and most of the previously reported OER catalysts. Quantitative measurements confirmed that for OER in 1 M KOH electrolyte the Bi/2D-Co3O4 catalyst was ~400 times more stable than the commercial IrO2 catalyst. The presence of stable high-valent Bi and the formation of distinctive (Bi-O-Co)n species are proposed to account for both the activity enhancement and the extreme stability of our Bi/2D-Co3O4 OER catalyst.

Stable Bi/2D-Co3O4 for oxygen evolution reaction

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.