Controllable synthesis method and applications of novel palladium-carbon nano composite catalyst

Abstract

The invention relates to a controllable synthesis method of a palladium-carbon nano composite catalyst. Cane sugar is taken as the carbon source; highly water soluble carbon quantum dots are synthesized by a hydrothermal method; the reductive oxygen containing groups on the surface of the carbon quantum dots are utilized to reduce divalent palladium ions Pd (II) into zero valent palladium withoutadding any other reducing agent; groups on the surface of the quantum dots are cross-linked in an oil bath in a reflux mode so as to form a thin carbon layer, and the palladium nano particles are fixed and dispersed on the thin carbon layer to obtain the novel palladium-carbon nano composite catalyst. The synthesis method has the advantages that palladium can be fixed without adding a stabilizingagent or another carrier; the activity of palladium in the palladium-carbon nano composite catalyst is not weakened, and the performance of the catalyst on catalytically reducing nitro-aromatic compounds is further improved. The size of palladium in the palladium-carbon nano composite catalyst can be controlled to be 5 nm or less; the activity of the catalyst is high; and the catalyst has a good effect on catalyzing the reduction reactions of nitro-aromatic compounds.

Description

technical field [0001] The invention relates to a catalyst applied to the hydrogenation reduction of nitroaromatic compounds, in particular to a controllable synthesis method and application of a palladium-carbon nanocomposite catalyst. Background technique [0002] Palladium carbon catalyst is a supported catalyst formed by loading metal nano-palladium into carbon materials. It is widely used in the chemical industry, especially for the hydrogenation reduction of nitroaromatic compounds. It has a good catalytic effect. Studies have shown that its catalytic activity is strongly affected by factors such as the size, morphology and surface properties of nanocatalysts (Synthetic Communications, 2008, 38(17), 2889-2897). According to the characteristics of nanoparticles, the smaller the particle, the more dangling bonds on the surface and the more active sites, the higher the catalytic activity. However, the synthesis of monodisperse metal nanomaterials with a particle size of l...

AI Technical Summary

Problems solved by technology

Most of the palladium-carbon catalysts reported in the literature or involved in the patent use activated carbon as a carrier, and the impregnation reduction method is used to load metal palladium. Although this method is simple, the disadvantage is that it cannot effectively control the particle size and the size of the metal nano-palladium. Its uniform dispersion on the activated carbon carrier greatly limits the activity of the palladium carbon catalyst

Other methods for synthesizing carbon-based / palladium (Pd) composite materials such as reduction under supercritical conditions (US patent no. US5973206A), burning with reducing gas, adding a large amount of strong reducing agent and photoreduction, etc. (New Journal of Chemistry, 2018 , 421771-1778; Nanoscale, 2014, 6, 6609-6616; Tetrahedron, 2017, 73, 5585-5592), high energy consumption and complicated operation

Therefore, it is still challenging to uniformly and stably load palladium nanoparticles on the surface of carbon materials in a simple and controllable manner.

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