ZIF-8 nanoparticles thin film at an oil-water interface as an electrocatalyst for the methanol oxidation reaction without the application of noble metals

Herein, the first example of a zeolitic imidazolate framework-8 (ZIF-8) nanostructured film at an oil-water interface is reported. This facile formation was conducted at room temperature, and the obtained film exhibited an excellent current density (32.7 mA cm(-2)) in the methanol oxidation process of fuel cells as compared to a Pt film (30.6 mA cm(-2)), Pd/ZIF (9.0 mA cm(-2)), Au-mercaptoacetic acid-HKUST-1 (0.3 mA cm(-2)), Ni/ZIF-8 (0.744 mA cm(-2)) and Co-MOF-71/graphene oxide (17.5 mA cm(-2)), where MOF indicates a metal-organic framework. The electrocatalytic activity of the ZIF-8 thin film was investigated using cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy and linear sweep voltammetry. Our results show that the long-term poisoning rate (delta) of the ZIF-8 film with delta = 0.1% is comparable to that of expensive catalysts and even that of the Pt metal in PtRuIr/C in the crystalline form or amorphous form with delta = 0.1% or delta = 0.13%, respectively. The as-synthesized ZIF-8 film exhibited the significantly high power of 15.4 mW cm(-2) when compared with the membrane electrode assemblies/PtRu (6.8 mW cm(-2)) anode catalyst. Our result for the ZIF-8 film is comparable to the data reported for MOFs and also commercial Pt/C and Pt/C E-TEK; this suggests that the ZIF-8 film would be a good candidate as an electrocatalyst for the methanol oxidation reaction process.