SBA-15 supported Ni-Co bimetallic catalysts for enhanced hydrogen production during cellulose decomposition

SBA-15 supported Ni-Co bimetallic catalysts with various loadings and Ni/Co ratios were prepared by incipient wetness impregnation and tested as catalysts in the pyrolytic decomposition of methyl cellulose. A thermogravimetric analyser coupled with a mass spectrometer (TG-MS) was used to examine the activity and selectivity for H(2) production by semi-quantitative analysis, and the new catalysts were compared with monometallic Ni and Co supported on SBA-15 and MCM-41. Catalysts were characterized by physisorption, chemisorption, reducibility test, X-ray diffraction, and scanning and transmission electron microscopy. 10 wt.% NiCo(2)/SBA-15 was the most active bimetallic catalyst, yielding 295 ml H(2)/g cellulose. The addition of water further enhanced the H(2) yield to 405 ml/g cellulose and gave an H(2) selectivity of up to 28.9 vol.%. This superior performance over monometallic catalysts indicated a synergy between Ni and Co, combining and enlarging individual activity and selectivity upon the main heterogeneous reactions. The improved reducibility and dispersion of Ni-Co alloying sites also contributed to this enhancement. (C) 2010 Elsevier B.V. All rights reserved.