MOF derived C/Co@C with a “one-way-valve”-like graphitic carbon layer for selective semi-hydrogenation of aromatic alkynes

Carbon-based materials are attractive in heterogeneous catalysis. In addition to be an ideal support for catalytic active species, carbon can form a protecting layer for non-noble metal nanoparticles (NPs) to prevent them from being oxidized. However, the synthesis of carbon supported non-noble metal NPs, with an even distribution of these transition metal NPs coated by a carbon shell, is still challenging. In this work, carbon supported metallic Co NPs coated by a graphitic carbon layer (C/Co@C) was successfully synthesized via calcinating of Co-MOF-74 at 1000 °C. The highly selective semi-hydrogenation of aromatic alkynes with NaBH4 to produce aromatic alkenes was realized over the as-obtained C/Co@C, in which the graphitic carbon layer acts like a “one-way valve” to allow BH4− to flow through, while preventing the larger size aromatic alkyne from entering the carbon shell to avoid its excessive hydrogenation. This work highlights the important role of using MOFs as precursor to prepare stable supported metal NPs for heterogeneous catalysis.