Efficient Atomically Dispersed Co/N-C Catalysts for Formic Acid Dehydrogenation and Transfer Hydrodeoxygenation of Vanillin.

Abstract

Atomically dispersed catalysts have gained considerable attention due to their unique properties and high efficiency in various catalytic reactions. Herein, a series of Co/N-doped carbon (N-C) catalysts was prepared using a metal-lignin coordination strategy and employed in formic acid dehydrogenation (FAD) and hydrodeoxygenation (HDO) of vanillin. The atomically dispersed Co/N-C catalysts showed outstanding activity, acid resistance, and long-term stability in FAD. The improved activity and stability may be attributed to the high dispersion of Co species, increased surface area, and strong Co-N interactions. XPS and XAS characterization revealed the formation of Co-N3 centers, which are assumed to be the active sites. In addition, DFT calculations demonstrated that the adsorption of formic acid on single-atom Co was stronger than that on Co13 clusters, which may explain the high catalytic activity. The Co/N-C catalyst also showed promising performance in the transfer HDO of vanillin with formic acid, without any external additional molecular H2.