Cluster‐like Co ₄ N embedded into carbon sphere as an efficient, magnetic‐separated catalyst for catalytic hydrogenation

Abstract

Abstract The transition metal nitrides are promising catalyst in catalytic fields. The decrease of particle size is favourable to improve the catalytic ability, but its synthesis remains a challenge due to high calcination temperature in the synthesis. Here, we have reported the designed synthesis of cluster‐like Co 4 N paticles (NPs) uniformly embedded in N‐doped carbon microsphere (Co 4 N@NC) by controllable nitridation of a spherical Co‐HQ−S composed of Co 2+ and 8‐hydroxy quinoline (8‐HQ), and its used as efficient hydrogenation catalyst. The Co 4 N have less size about 3 nm benefited the confined effect of carbon matrix. The small size is favorable to develop the catalytic ability of Co 4 N and a protection by carbon can enhance its stability. The test indicated that Co 4 N/NC can act effective catalysts for the hydrogenation by taking the conversion of 4‐nitrophenol (4‐NP) to 4‐aminophenol (4‐AP) as model. The rate constant of 4‐NP conversion is 1.14 min −1 at 25 °C (5 mg of catalyst), much higher than many non‐noble metal catalyst and even comparable to noble metal catalysts. The Co 4 N/NC can be easily separated by a external magnet with good reuse performance. Importantly, the catalytic ability can be further enhanced by slight increase of the dose of catalyst, and/or reaction temperature. The combination of magnetic property and good catalytic ability makes the Co 4 N/NC large promising in catalytic fields.