Boosting the electro-oxidation of 5-hydroxymethyl-furfural on a Co-CoS x heterojunction by intensified spin polarization.

The conversion of biomass-derived platform molecules ( e.g. , 5-hydroxymethyl furfural (HMF)) represents a sustainable route to produce value-added chemicals. Here we report the fabrication of an N-doped carbon nanotube assembled yolk-shell polyhedron with embedded Co-CoS x nanoparticles (NPs) (Y-Co-CoS x @CN) for efficient HMF electrooxidation. DFT calculations demonstrate that the formation of the heterojunction could intensify spin polarization in Co-CoS 2 , thus achieving effective d-p coupling between the catalyst and reactant/intermediate. As expected, Y-Co-CoS x @CN exhibits excellent HMF electro-oxidation activity at a low applied potential of 1.29 V vs. RHE at 10 mA cm -2 in 0.1 M KOH with 5 mM HMF, affording an FDCA yield of 96% and FE of 93.5%. This work not only sheds light on the catalytic nature of the heterojunction and the underlying mechanisms for the enhancement of HMF electro-oxidation activity, but would also provide a descriptor for the rational design of advanced electro-catalysts.