Decoration of NiO hollow spheres composed of stacked nanosheets with CeO2 nanoparticles: Enhancement effect of CeO2 for electrocatalytic methanol oxidation

High-performance and low-cost electrocatalysts for electrochemical methanol oxidation reaction (MOR) are essential for the wide application of direct methanol fuel cells (DMFC). Herein, CeO 2 –NiO composites with CeO 2 nanoparticles homogeneously supported on the surface of NiO hollow spheres composed of stacked nanosheets are synthesized via a facile two-step route and tested as noble-metal-free electrocatalysts towards methanol oxidation in alkaline solution. Optimal loading of CeO 2 nanoparticles with a uniform size of ∼8 nm greatly enhances the electrocatalytic activity and stability comparing with pristine NiO hollow spheres for MOR. It is proposed that a synergistic effect resulting from the proper loading content and high dispersion of CeO 2 nanoparticles on the surface of NiO nanosheets boosted the formation of active NiOOH species, which enhanced the electrocatalytic activity and stability of CeO 2 –NiO catslysts for MOR. CeO 2 nanoparticles exhibit good promotion effect as co-catalyst in electrocatalysis , and CeO 2 –NiO nanocomposites show potential as inexpensive anode catalysts for DMFC applications .