Activating bulk nickel foam for the electrochemical oxidization of ethanol by anchoring MnO2@Au nanorods

Direct ethanol fuel cells (DEFCs) using biomass-derived fuel is a promising sustainable energy conversion system for enabling a carbon-neutral society. However, such an imperative task is impeded by the stability-deficiency of powdery catalysts and the activity-weakness of bulk non-noble metal catalyst for the ethanol oxidation reaction (EOR). In the present study, a surface-modification strategy for activating the EOR ability of bulk non-noble nickel foam is demonstrated. The anchored MnO2@Au nanorods on nickel foam induced strong interfacial interactions between the nickel foam and MnO2 nanorods as well as Au nanoparticles, providing not only more reactive sites but also enhanced ion transportation. Resultantly, the functionalities of the bulk nickel foam as both a current collector and catalyst were integrated into one alliance. Benefiting from such a hieratical microstructure and well-defined composition design, the MnO2@Au-modified bulk nickel foam presented 31% increase in steady current density at 1.8 V vs. RHE, 28% decrease in the Tafel slope, and 40% more reactive sites compared with the bare nickel foam, outperforming most nickel-based candidates. Such a special surface-structure reconstruction embraced the current-collector functionality together with the catalytic functionality, which mitigates the stability-weakness puzzle for powdery catalysts and activity-deficiency for bulk nickel current collectors at the same time, providing new insights for the design of electrodes for DEFCs.

Automated summary

A surface-modification strategy is demonstrated to activate the ethanol oxidation reaction (EOR) ability of non-noble metal nickel foam, leading to high efficiency conversion of ethanol. The modified nickel foam showed a 31% increase in steady current density at 1.8 V vs. RHE, a 28% decrease in Tafel slope, and a 40% increase in reactive sites compared to the bare nickel foam, outperforming most nickel-based candidates.