posted on 2016-02-22, 00:00authored byGang Liu, Liang Zeng, Zhi-Jian Zhao, Hao Tian, Tengfang Wu, Jinlong Gong
Compared to metallic platinum and
chromium oxide, zinc oxide (ZnO)
is an inexpensive and low-toxic alternative for the direct dehydrogenation
of propane (PDH). However, besides the limited activity, conventional
zinc-based catalysts suffer from serious deactivation, because of
ZnO reduction and/or carbon deposition. Considering the high cost
of platinum, reducing the amount of platinum in the catalyst is always
desirable. This paper describes a catalyst comprising ZnO modified
by trace platinum supported on Al2O3, where
the Zn2+ species serve as active sites and platinum acts
as a promoter. This catalyst contains less platinum than traditional
platinum-based catalysts and is much more stable than conventional
ZnO catalyst or commercial chromium-based systems during PDH. It is
proposed that ZnO was promoted to a stronger Lewis acid by platinum;
thus, easier C–H activation and accelerated H2 desorption
were achieved.