Cluster‐like Co₄N embedded into carbon sphere as an efficient, magnetic‐separated catalyst for catalytic hydrogenation

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-HQÀ 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 À 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.

Generation of dual anion vacancies on CeO2/Co4N interfaces to facilitate hydrogen evolution reaction in alkaline solution

“…2b, the three binding energies at 779.14, 781.00, and 782.56 eV correspond to the Co-Co bond, Co-N bond, and Co-O bond, respectively. [31][32][33] Co-Co and Co-N bonds exist in the Co 4 N structure, while the Co-O bond is generated by the oxidation of the sample in air and in the Co-O-Ce bonds between Co 4 N and CeO 2 . It can be observed that after the formation of a heterostructure with CeO 2 , the binding energy corresponding to the Co-Co bond shows a tendency to move to a higher energy, showing electron loss in the Co 4 N. However, after the introduction of the plasma treatment, the binding energy clearly moved in a lower direction, showing an electron-accepting state.…”

In situ conversion of Co–CoN nanowires into ultrathin 2D nanosheets for highly effective catalytic hydrogenation

“…21 Co 4 N combined with carbon showed good activity for the hydrogenation of p -nitrophenol. 22–24 Through the construction of heterostructures, the catalytic performance can be further tuned based on the positive role of a heterointerface for optimizing the electronic structure. 25–30 The Co 2 N/Co showed improved performance for hydrogen electrochemistry.…”

Supported transition metal (Mo, W) carbide and nitride catalysts for lignin hydrodeoxygenation: interplay of supports, structure, and catalysis

“…This allows these catalytic materials to meet the requirements for long periods under harsh reaction conditions. In addition, some late TMCs and TMNs have processed magnetic properties and can be recovered by external magnetic fields after being spent, 34,35 which makes them possess certain advantages in industrial catalysis. Despite these advantages, the application of transition metal carbide and nitride catalysts in the catalytic conversion of lignin and its model compounds is limited, especially for nitride.…”