Platinum/carbon nanotube catalyst, the preparation process and use thereof

摘要

A platinum/carbon nanotube catalyst applicable to heterogeneous asymmetric hydrogenation, which is fabricated by supporting platinum on carbon nanotube carriers, and prepared by the steps of: heating purified carbon nanotubes in nitric acid, filtering and washing the same with water until pH value of the filtrate becomes neutral, drying the carbon nanotubes; immersing the carbon nanotube carriers obtained in an aqueous chloroplatinic acid solution and carrying out ultrasonic treatment at room temperature; immersing the mixture of the carbon nanotubes and the aqueous chloroplatinic acid solution under stirring; drying the material by heating to 110° C. from room temperature and maintaining this temperature; grinding the product to fine powders, reducing the fine powders with an aqueous sodium formate solution under a heating condition, filtering and washing the product with deionized water, and drying the product.

主权项

1. A platinum/carbon nanotube catalyst for heterogeneous asymmetric hydrogenation wherein platinum nanoparticles are loaded on the outer surfaces of the tube cavities of carbon nanotubes, said platinum/carbon nanotube catalyst takes carbon nanotubes as carriers, and said platinum nanoparticles are 2-10 wt % based on the weight of the carbon nanotubes loaded with the platinum nanoparticles, wherein the platinum/carbon nanotube catalyst is prepared by the steps of:
1) preparing carbon nanotube carriers by treating purified carbon nanotubes in nitric acid at 110-160° C. for 4-16 hours, filtering and washing the carbon nanotubes with water until pH value of the filtrate becomes neutral, drying the carbon nanotubes at 50-120° C. so as to obtain functionalized carbon nanotube carriers; 2) adding xylene to the carbon nanotube carriers under stirring and carrying out ultrasonic treatment for 1-4 hours; 3) adding an aqueous chloroplatinic acid solution to the product obtained in step 2) under stirring, and then adding deionized water, and stirring the product continuously for 15-30 minutes; 4) adding sodium formate with a purity ≧99.5 wt % to the product obtained in step 3) to perform reduction at 70-120° C. under stirring for 0.5-3 hours, and cooling the product; 5) after cooling and layer separation, decanting a supernatant, adding absolute ethanol and stirring for dispersion, and carrying out separation; and 6) dispersing the product obtained in step 5) into deionized water, filtering, and washing with water until pH value of the filtrate becomes neutral, drying at 50-120° C. so as to obtain a platinum/carbon nanotube catalyst wherein platinum nanoparticles are loaded on the outer surfaces of the tube cavities of carbon nanotubes.