posted on 2021-06-21, 18:45authored byYanming Cao, Jingmin Ge, Meihong Jiang, Fazhi Zhang, Xiaodong Lei
The
confirmation and regulation of active sites are particularly
critical for the design of methanol oxidation reaction (MOR) catalysts.
Here, an acid etching method for facet control combined with defect
construction was utilized to synthesize Co3O4 nanoparticles on nickel foam for preferentially exposing the (311)
facet with enriched oxygen vacancies (VO). The acid-leached
oxides exhibited superior MOR activity with a mass activity of 710.94
mA mg–1 and an area-specific activity of 3.390 mA
cm–2 as a result of (i) abundant active sites for
MOR promoted by VO along with the highly active (311) facet
being exposed and (ii) phase purification-reduced adsorption energy
(Eads) of methanol molecules. Ex situ
X-ray photoelectron spectroscopy proved that highly active CoOOH obtained
via the activation of plentiful Co2+ effectively improved
the MOR. Density functional theory calculations confirmed that the
selective exposed (311) facet has the lowest Eads for CH3OH molecules. This work puts forward
acid etching as the facet modification and defect engineer for nanostructured
non-noble catalysts, which is expected to result in superior electrochemical
performance required for advanced alkaline direct methanol fuel cells.