Carbon Dots Promote the Performance of Anodized Nickel Passivation Film on Ethanol Oxidation by Enhancing Oxidation of the Intermediate(dagger)

Main observation and conclusion Ethanol is considered a better fuel than methanol in direct alcohol fuel cells because of the high energy density and low toxicity. Compared with noble metal catalysts, nickel-based catalysts are much cheaper in price. However, present nickel-based catalysts still surfer from some disadvantages such as low activity and high overpotential. In this paper, we show a new and high efficient nickel- based catalyst for ethanol oxidation. A layer of anodized nickel passivation film (Ni-APF) was formed on the surface of nickel sheet by anodic oxidation method with carbon dots (CDs) as co-catalyst. At the current density of 110 mA center dot cm(-2), the potential for Ni-APF/CDs was only 0.541 V (vs. Ag/AgCl), which was 18.8% lower than that of Ni-APF. Low overpotential could reduce electrode thermal loss and increase output energy. Ni-APF/CDs showed 144.4 mA center dot cm(-2) peak current density at peak potential 0.662 V (vs. Ag/AgCl), which was 31% higher than that of Ni-APF (110.3 mA center dot cm(-2)). In this system, CDs mainly function in the increase of charge-transfer capacity and the promotion oxidation of carbonaceous intermediates.

Automated summary

In this study, a high efficient nickel-based catalyst for ethanol oxidation, Ni-APF/CDs, was shown to have low overpotential and high peak current density at a current density of 110 mA·cm(-2), reducing electrode thermal loss and increasing output energy. The carbon dots (CDs) in the system mainly function in increasing charge-transfer capacity and promoting the oxidation of carbonaceous intermediates.