Pt/C Catalysts For Hydrogen Evolution From Decalin Under Microwave Heating

In the present work, different carbon materials were tested in a 700W microwave oven regarding their microwave absorbing capacity. CNTs were found to be the best microwave absorber. Pt/CNT catalysts were prepared and their catalytic performance was tested in the process of decline dehydrogenation. CNFs/GF composite were synthesized by virtue of in-situ growth of CNFs on GF substrate, and the Pt/CNFs/GF structured catalyst was applied in dehydrogenation of decalin. The results of this paper are as follows:(1) Carbon materials are very good absorbents of microwaves. In this paper, different carbon materials including carbon nanotubes (CNTs), carbon nanofibers, carbon black, flaky graphite and activated carbon were tested in a 700W microwave oven regarding their microwave absorbing capacity. And in view of their structural properties and catalytic performance of Pt supported on them, CNTs were found to be the best carrier.(2) Firstly, the effect of different reactors, different microwave oven power, preparation methods, reduction temperature, Pt loading and raw material configuration has been discussed in this paper. The result shows that catalytic performance of Pt/CNTs catalyst prepared by EG process method was better. The result of 0.20g 5wt% Pt/CNTs catalyst applied in dehydrogenation of 40ml decalin in an eggplant-shaped reactor (φmax=54mm) under microwave heating was best. And an TOF of 846.0mol H2/moI metal in 2 hour. The actual temperature (called hot spots) at the surface of Pt/CNTs catalyst was higher than the overall solvent. In other words, the microwave reaction would be performed at the catalyst surface as compared with the conventional reaction. So TOF was higher under microwave heating. And there are no obvious differences between the XRD pattern of the spent catalyst in the microwave and conventional reaction.(3) CNFs/GF composite were synthesized by virtue of in-situ growth of CNFs on GF substrate, and the Pt/CNFs/GF structured catalyst was applied in dehydrogenation of decalin. CNFs/GF composite possessed the typical mesoporous structure of CNFs and its BET surface area became bigger. Moreover, this composite possessed good abrasion resistance. The effect of CNFs/GF with different CNFs loadings has been discussed in this work. When CNFs relative yield was 1.25, catalytic performance of Pt/CNFs/GF catalyst was best. Catalytic performance of Pt/CNFs/GF catalyst prepared by impregnation method was better that by EG process method.