Spatial decoupling of dehydrogenation and CO oxidation by Ni-Co-Ti hierarchical trimetallic catalyst for electrocatalytic oxidation of methanol

Methanol electro-oxidation reaction (MOR) is the kernel of methanol fuel cell. When the multi-step microscopic transformations process of MOR couples and occurs on the same active site, undoubtedly it reduces the probability of reaction and increases the steric hindrance, resulting in slow reaction kinetics and degradation of catalytic performance. In order to decouple the dehydrogenation and CO oxidation in MOR, herein we synthesized the hierarchical catalyst (NiCo/N-TiO2 @NaOH) with bifunctional spatial distribution, which displayed 73 mA cm−2 at the potential of 1.5 V (vs. RHE) and only 20 % degradation of performance after continuously electrolysis over 40,000 s. Based on analysis of mass transfer and electron transport in hierarchical structure, combining with in-situ mass spectrometry and theory calculation, the high MOR performance of NiCo/N-TiO2 can be ascribed to the spatial decoupling the MOR reactions including dehydrogenation under synergic effect of Ni/Co and CO oxidation on N-TiO2 film.