Reduction of the Synthesis Temperature of Ni2P/SiO2 by Pd Addition

V. TEIXEIRA DA SILVA; R.M. AMORIM; L. ANDRINI; E. J. LEDE; F.G. REQUEJO

Philadelphia, Pennsylvania, USA

Conferencia; 19th North American Meeting; 2005

North American Catalysis Society

The tightening of the environmental regulations concerning the maximum allowed levels of sulfur, nitrogen and aromatics in fuel has led to a search for new hydrotretaing catalysts more active than the currently employed in the oil industry. Several approaches have been taken including the improvement of existing sulfide catalysts and the investigation of new active phases such as carbides, nitrides, and catalysts containing noble metals [1-3]. Transition metal phosphides, and in particular Ni2P/SiO2, are a new class of catalysts highly active for hydrodesufurization and  hydrodenitrogenation reactions of oil fractions. However, the Ni2P/SiO2 synthesis temperature is very high for industrial standards (¡­ 993 K) [4]. In this work, different loadings of Pd (0.1, 0.5, 1.0%) were incorporated to a 43%Ni2PO4/SiO2 sample aiming the lowering of the transformation temperature phosphate ¡æ phosphide. Temperature-programmed reduction results show that while the reduction profile of the 43% (w/w) Ni2PO4/SiO2 sample presents only one peak with maximum at 993 K, the profile of the sample containing 1% Pd presents such a maximum located at 772 K. The effects of the reduction temperature on the phosphorous K-edge were studied in situ by X-Ray Absorption Near Edge Structure (XANES) also showing, in agreement with TPR results, that Pd presence leads to a substantial decrease in the Ni2PO4 ¡æ Ni2P transformation temperature.2P/SiO2, are a new class of catalysts highly active for hydrodesufurization and  hydrodenitrogenation reactions of oil fractions. However, the Ni2P/SiO2 synthesis temperature is very high for industrial standards (¡­ 993 K) [4]. In this work, different loadings of Pd (0.1, 0.5, 1.0%) were incorporated to a 43%Ni2PO4/SiO2 sample aiming the lowering of the transformation temperature phosphate ¡æ phosphide. Temperature-programmed reduction results show that while the reduction profile of the 43% (w/w) Ni2PO4/SiO2 sample presents only one peak with maximum at 993 K, the profile of the sample containing 1% Pd presents such a maximum located at 772 K. The effects of the reduction temperature on the phosphorous K-edge were studied in situ by X-Ray Absorption Near Edge Structure (XANES) also showing, in agreement with TPR results, that Pd presence leads to a substantial decrease in the Ni2PO4 ¡æ Ni2P transformation temperature.2PO4/SiO2 sample aiming the lowering of the transformation temperature phosphate ¡æ phosphide. Temperature-programmed reduction results show that while the reduction profile of the 43% (w/w) Ni2PO4/SiO2 sample presents only one peak with maximum at 993 K, the profile of the sample containing 1% Pd presents such a maximum located at 772 K. The effects of the reduction temperature on the phosphorous K-edge were studied in situ by X-Ray Absorption Near Edge Structure (XANES) also showing, in agreement with TPR results, that Pd presence leads to a substantial decrease in the Ni2PO4 ¡æ Ni2P transformation temperature. References 1. Greening, P. Top. Catal. 16/17, 5, (2001) 2. Bertelsen, B. I. Top. Catal. 16/17, 15, (2001) 3. Knudsen, K.G., Cooper, B.H., and Topsoe, H. Appl. Catal. A: General 189, 205 (1999). 4. Oyama, S. T. J. Catal. 216, 343, (2003)Top. Catal. 16/17, 5, (2001) 2. Bertelsen, B. I. Top. Catal. 16/17, 15, (2001) 3. Knudsen, K.G., Cooper, B.H., and Topsoe, H. Appl. Catal. A: General 189, 205 (1999). 4. Oyama, S. T. J. Catal. 216, 343, (2003)Top. Catal. 16/17, 15, (2001) 3. Knudsen, K.G., Cooper, B.H., and Topsoe, H. Appl. Catal. A: General 189, 205 (1999). 4. Oyama, S. T. J. Catal. 216, 343, (2003)Appl. Catal. A: General 189, 205 (1999). 4. Oyama, S. T. J. Catal. 216, 343, (2003)J. Catal. 216, 343, (2003) http://www.nacatsoc.org/19nam/19NAM_PosterPresentations.pdf http://www.nacatsoc.org/19nam/program.asp?SessionID=03&TypeID=D