Synergistic Coupling Derived Cobalt Oxide with Nitrogenated Holey Two-Dimensional Matrix as an Efficient Bifunctional Catalyst for Metal-Air Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 31026145.
- Also identified by DOI 10.1021/acsnano.9b00320.
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Abstract
Developing cost-effective, efficient bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is the heart of metal-air batteries as a renewable-energy technology. Herein, well-distributed nanopolyhedron (NP) Co<sub>3</sub>O<sub>4</sub> grown on iron (Fe) encapsulated in graphitic layers on a nitrogenated, porous two-dimensional (2D) structure, namely, a C<sub>2</sub>N matrix, (NP Co<sub>3</sub>O<sub>4</sub>/Fe@C<sub>2</sub>N), presents an outstanding bifunctional catalytic activity with a comparable overpotential and Tafel slope to those of benchmark Pt/C and IrO<sub>2</sub>. The rationally designed atomic configuration of Co<sub>3</sub>O<sub>4</sub> on the C<sub>2</sub>N matrix has a well-controlled NP morphology with a (111) plane, leading to bifunctional activities for the ORR and OER. Interestingly, the specific interaction between the NP Co<sub>3</sub>O<sub>4</sub> nanoparticles and the C<sub>2</sub>N matrix introduces synergistic coupling and changes the electronic configuration of Co atoms and the C<sub>2</sub>N framework. Benefiting from the synergistic coupling of Co<sub>3</sub>O<sub>4</sub> with the C<sub>2</sub>N matrix, the NP Co<sub>3</sub>O<sub>4</sub>/Fe@C<sub>2</sub>N electrocatalyst exhibits exceptionally high stability and an even lower charge-discharge overpotential gap of 0.85 V at 15 mA cm<sup>-2</sup> than that of the Pt/C+IrO<sub>2</sub> catalyst (1.01 V) in Zn-air batteries. This work provides insights into the rational design of a metal oxide on a C<sub>2</sub>N matrix for bifunctional, low-cost electrochemical catalysts.