Preferential Growth of the Cobalt (200) Facet in Co@N–C for Enhanced Performance in a Fenton-like Reaction

Herein, a series of Co@N–C materials are synthesized using nitrates (LiNO3, NaNO3, and KNO3) as templates to control the preferential growth of the cobalt (200) facet. Co@N–C–X (X = LiNO3, NaNO3, and KNO3) exhibit excellent activities and long-term stabilities for Fenton-like degradation of bisphenol A (BPA) with peroxymonosulfate (PMS) as an oxidant. The texture coefficient (TC) is used to investigate the relationship between the Co facets and their catalytic activities, and a linear relation is built between the TC of Co(200) and the reaction rate constant (k). Co(200) is therefore the most active facet for PMS activation, while nitrates can promote the preferential growth of the Co(200) facet. Moreover, the Co(200) facet is more stable against leaching and can achieve more quick transformation between Co2+/Co3+. Quenching tests, electron paramagnetic resonance spectra, and electrochemical tests show that singlet oxygen (1O2) plays the dominant role for BPA degradation. Density functional theory verifies that Co nanoparticles coated with a graphitic nitrogen-doped carbon layer have the best activity for PMS activation. This work first proposes the strategy of using nitrates to control the preferential growth of Co facets and reveals the relationship between the TC value and k, thus attracting great interest in the environmental field.