Jianxin Lin

Preparation and Characterization of Carbon Nanotubes-Coated Cordierite for Catalyst Supports

Abstract The carbon nanotubes-coated cordierite (CNTs-cordierite) was fabricated by pyrolysis of ethine on cordierite with iron catalyst, which was penetrated into the cordierite substrate by vacuum impregnation. The cordierite substrate, carbon naontubes, and CNTs-cordierite were characterized by SEM, TEM/HREM, BET, and TGA. The results show that the carbon nanotubes were distributed uniformly on the surface of cordierite. A significant increase in BET surface area and pore volume was observed, and a suitable pore-size distribution was obtained. On the CNTs-cordierite, carbon nanotubes penetrated into the cordierite substrate, which led to a remarkable stability of the CNTs against ultrasound maltreatment. Growth time is an important factor for thermostability and texture of the sample. The mass increased but the purity decreased with the growth time, which caused the exothermic peak shift to low temperature, and the corresponding full width half maximum (FWHM) of the peak in DTG increased.

A novel fused iron catalyst for ammonia synthesis promoted with rare earth gangue

Abstract Rare earth gangue, which mainly consists of mixtures of light rare earths such as lanthana, ceria, neodymium oxide and praseodymium oxide, was used as the promoter of fused iron catalysts for ammonia synthesis. The result showed that the activity of the catalyst promoted with rare earth gangue was comparable with those of commercial iron catalysts with high amount of cobalt. The role of rare earths was owed to their advantages for favoring the deep reduction of the main composite in catalyst, i.e., iron oxide. This finding indicated that the use of rare earth gangue could decrease the content of cobalt or even completely replace cobalt, which was used to be regarded as unsubstitutable promoters for high performance ammonia catalyst; therefore, the cost of fused iron catalysts would decrease significantly.

Ruthenium Ammonium Chloride as a Precursor for the Preparation of High Activity Catalysts for Ammonia Synthesis

Abstract Ruthenium ammonium chloride, Ru(NH 3 ) 5 Cl 3 , was prepared by the chemical reaction of ruthenium chloride with hydrazine hydrate and used as a novel ruthenium precursor for the preparation of activated carbon (AC)-supported Ru catalysts for ammonia synthesis. The results from TEM and CO chemisorption show that the Ru nanoparticles on the RuN/AC catalyst prepared from the Ru(NH 3 ) 5 Cl 3 precursor have much higher dispersion and more uniform size distribution than that on the Ru/AC catalyst from the RuCl 3 precursor. The activity of the RuN/AC catalyst for ammonia synthesis was increased by more than 10% compared with the Ru/AC catalyst under the reaction conditions of 10 MPa and 10u2008000 h −1 .