Construction of highly-dispersed and composition-adjustable CoxN in stable Co@CoxN@C nanocomposite catalysts via a dual-ligand-MOF strategy for the selective hydrogenation of citral.

The nanocomposites of Co nanoparticles with composition-adjustable Co X N composited on surface in carbon coverage (Co@Co x N@C) were feasibly prepared upon a dual-ligand MOF manipulating strategy, the highly dispersed Co x N on Co matrix was quite efficient for activating C O and lowering the reaction activation energy (Ea), leading to the superior TOF and yield for selective hydrogenation of citral to nerol and geraniol. • Efficient and stable Co@Co x N@C nanocomposite catalysts for citral hydrogenation were feasibly acquired from a dual-ligand-MOF manipulating strategy. • The composition of exposed Co x N could be conveniently adjusted from the strategy. Interstitial compounds with tunable surface properties are highly desirable for advanced applications. Here, we present a dual-ligand-metal-organic framework (MOF) strategy to synthesize Co N C catalysts for the selective hydrogenation of citral. The dual-ligand MOF was synthesized by coordinating Co with both a N-donor ligand and a benzenedicarboxylic acid ligand, and calcining in a N 2 atmosphere at 973, 1073, or 1173 K. The Co N C catalysts derived from this strategy were Co nanoparticles (10.0–20.0 nm in diameter) with composite Co/Co x N surfaces covered in a layer of carbon (Co@Co x N@C). The highest Co x N surface composition, 0.54, was achieved when the precursor was calcined at 1073 K; this catalyst exhibited 100% citral conversion with 98% selectivity for the desired products (up to 60% selectivity for the most valuable C O hydrogenation product) and a superior turnover frequency (TOF) of 0.56 s−1. In-situ IR spectra and kinetic investigations were used to confirm that the exposed Co x N on the Co@CoxN@C nanostructures contributed to activating the C O bond and facilitating the transformation of citral to the desired C O hydrogenation products. The results of this study suggest that this dual-ligand-MOF strategy could be used to construct efficient interstitial compounds for advanced applications. [ABSTRACT FROM AUTHOR]