Abstract:
A unique strategy to obtain highly efficient electrocatalysts
based on the spinel Ni0.5Cu0.5Co2O4 and mesoporous ZSM-5 (Zeolite Socony
Mobil-5) is reported here for methanol oxidation in an alkaline medium. To
develop an efficient catalyst, Ni2+−Cu2+ ion-exchanged mesoporous ZSM-5
and Ni0.5Cu0.5Co2O4 are prepared. 30 wt % of Ni0.5Cu0.5Co2O4 decorated
Ni2+−Cu2+ ion-exchanged mesoporous ZSM-5 exhibits exceptionally higher
catalytic activity with reasonably low onset potential than that of
Ni0.5Cu0.5Co2O4, NiCo2O4, CuCo2O4, and Ni2+−Cu2+ ion-exchanged
mesoporous ZSM-5. Electrochemical oxidation of HCHO and HCOOH
also takes place over this catalyst at the same condition. The material exhibits
high current density (21.4 mA/cm2
) and stable electrocatalytic activity (with
99% retention) even after 1000 potential cycles. However, the benchmark
catalyst Pt(20%)/C exhibits low activity (1.6 mA/cm2
) and significant
deactivation phenomenon (with 25% activity retention) at the identical condition. The cooperative contributions provided by
Ni0.5Cu0.5Co2O4 and Ni2+−Cu2+ ion-exchanged mesoporous ZSM-5 support having Brö
nsted acidity, large external surface area,
and intercrystalline mesoporosity deliver excellent electrocatalytic activity. The ease of synthesis, scale-up, stable and exceptional
electrocatalytic activity paves the path toward the development of highly efficient alkaline direct methanol fuel cells.
