Strong metal-support interactions of Co-based catalysts facilitated by dopamine for highly efficient ammonia synthesis: in situ XPS and XAFS spectroscopy coupled with TPD studies.

We report a new strategy for strengthening metal-support interaction and stabilizing Co nanoparticles at high temperature. Through the use of dopamine and removal of carbon layers by thermal N2 treatment, ceria-based Co catalysts that are efficient and highly stable for ammonia synthesis can be obtained. The ammonia synthesis rate at 425 °C and 1 MPa is enhanced from 3.81 mmolNH3 gcat-1 h-1 over Co/CeO2 to 19.12 mmolNH3 gcat-1 h-1 over a dopamine-mediated catalyst. The superior catalytic performances of the dopamine-mediated Co/CeO2 catalyst are associated with smaller crystalline size, stronger metal-support interaction and lower N2 activation energy.