Enhanced methanol oxidation activity of porous layered Ni/CeO2@CN nanocomposites in alkaline medium

Abstract

The performance of direct methanol fuel cells (DMFC) partly depends on the development of economical and efficient methanol oxidation catalyst. Here, porous layered Ni/CeO2@CN-T composites were prepared by complexation and pyrolysis two-step methods. The optimal Ni/CeO2@CN-600 for methanol oxidation reaction (MOR) requires only 1.361 V at the current density (j) of 10 mA cm−2, and the j is as high as 229.56 mA cm−2 at 1.642 V, superior to those of the nickel-based catalysts reported. The excellent properties of Ni/CeO2@CN-600 are mainly attributed to the electronic interaction between Ni and CeO2, the uniform dispersion of Ni and CeO2 nanoparticles and its porous layered structure. Meanwhile, it has better stability after 12 h i-t tests. The CO poisoning experiments showed that the anti-CO poisoning ability of Ni/CeO2@CN-600 was obviously stronger than that of Pt/C catalyst in alkaline medium. Finally, the density functional theory (DFT) calculation shows the superior activity of Ni/CeO2 catalysts for MOR is mainly attributed to the higher adsorption energy of Ni/CeO2 for CH3OH and the lower energy barrier.