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

Abstract

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 mmol_NH3 g_cat⁻¹ h⁻¹ over Co/CeO₂ to 19.12 mmol_NH3 g_cat⁻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.