Catalytic katures of Ni/Ba-Ce_(0.9)-Y_(0.1) catalyst to produce hydrogen for PCFCs by methane reforming

摘要

Methane reforming in steam (SR), auto-thermal (ATR) and partial oxidation (POX) conditions over Ni/Ba-Ce_(0.9)-Y_(0.1) catalyst was investigated in the temperature range 500-700 ℃. Catalyst presents a satisfying activity in POX condition only. BCY carrier was not stable in the presence of CO_2 and, irrespective of reaction conditions, it reacts with CO_2 giving rise to the formation of BaCO_3 and CeO_2. The very low activity observed in SR conditions was due to the negative role exerted by water strongly absorbed on catalyst surface, limiting so the accessibility and reduction state of Ni active sites. In POX condition catalyst is active and satisfying H_2 yield can be reached by operating at T = 700 ℃. A significant reduction of coke formation was observed by operating in POX at 700 ℃. On the contrary, in ATR condition at the same reaction temperature huge amount of filamentous coke was observed.