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Corresponding Author

Liang Li(liliang@usst.edu.cn)

Abstract

High-performance electrocatalysts play a vital role in the commercial application of direct fuel cells. Current anode materials still have such problems as low activity, easy poisoning and high cost. In this study, a new type of nano- palladium (Pd) catalyst was prepared by dipping method using layered double hydroxides (LDHs) as the carrier. X-ray diffractometer, scanning electron microscope (SEM), inductively coupled plasma mass spectrometer (ICP-MS), energy spectrometer, transmission electron microscope (TEM), cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscope were used to analyze the structure and electrocatalytic performance of the catalyst. The results showed that the newly prepared Pd/Mg-Al-LDHs still maintained the layered structure of LDHs, and the metal Pd was evenly dispersed between the layers of hydrotalcite. Cyclic voltammetric curves showed that under alkaline conditions, the peak current density of Pd/Mg-Al-LDHs with 7% Pd in electrocatalytic ethanol was 36 mA·cm-2. The peak current density of commercial Pd/C in electrocatalytic ethanol was 30 mA·cm-2, and Pd/Mg-Al-LDHs exhibited better resistance to intermediate product poisoning. The factors including ethanol concentration, scanning rate and temperature were found to be effective, in particular, peak current had a direct effect. The chronoamperometric test revealed that Pd/Mg-Al-LDHs displayed higher electrocatalytic activity and stability toward ethanol than Pd/C, and the current density of Pd/Mg-Al-LDHs at 2000 s was 12 times to that of the commercial Pd/C. The electrochemical impedance data showed that Pd intercalation could significantly improve the conductivity of Mg-Al-LDHs and reduce the resistance to charge transfer during the electrocatalytic process.

Graphical Abstract

Keywords

palladium, electro catalysis, anode catalyst, layered double hydroxides, direct ethanol fuel cells

Publication Date

2021-02-28

Online Available Date

2021-02-28

Revised Date

2020-11-13

Received Date

2020-07-29

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