4. Conclusions
In
situ coupling strategy of CoFe alloy and CoxN
heterojunction encapsulated and embedded in the nitrogen-doped
lignin-derived carbon CoFe-CoxN@NC was provided to
create a novelty highly active and stable electrocatalyst for oxygen
evolution reaction. Biorefinery lignin was first carboxylated to improve
its solubility and precisely coordinated with metal ions to form the
coordination polymer precursor, that promoted the dispersion of metal
active component and the encapsulated grapheme lawyer of CoFe alloy and
CoxN heterojunction. CoFe-CoxN@NC
exhibited an excellent OER activity with the lowest overpotential of 270
mV at 10 mA·cm−2 and stability with the only increment
of 20 mV after 80000s in the alkaline media, comparable to that of
commercial Ir/C catalyst. The as-prepared catalyst with high activity
and cycle stability was attributed to the synergistic effect of CoFe
alloy, CoxN and nitrogen-doped encapsulated grapheme
lawyer, that reduce the adsorption strength between *O and CoFe alloy,
prevent metals leaching and agglomeration, and improve the electron
transfer efficiency. This method not only turned waste into treasure
from biomass waste lignin, but also provided a solution for the
replacement of precious metal catalysts in the field of renewable energy
conversion and storage.