A novel synthesis of Ni₂P/MCM-41 catalysts by reducing a precursor of ammonium hypophosphite and nickel chloride at low temperature

详细信息    查看全文

• 作者：Hua Song ; Min Dai ; Hualin Song ; Xia Wan ; Xiaowei Xu
• 关键词：Nickel phosphide ; Ammonium hypophosphite ; Nickel chloride ; MCM-41 ; Hydrodesulfurization ; Dibenzothiophene
• 刊名：Applied Catalysis A: General
• 出版年：2013
• 出版时间：10 July, 2013
• 年：2013
• 卷：462-463
• 期：Complete
• 页码：247-255
• 全文大小：2533 K

文摘

A novel method to prepare Ni₂P/MCM-41 catalysts at low reduction temperature based on ammonium hypophosphite and nickel chloride by temperature programmed reduction is described. The catalysts were prepared using incipient wetness impregnation of the siliceous MCM-41 support with aqueous solutions of ammonium hypophosphite and nickel chloride, followed by reducing the obtained precursor at 483-663 K for 2 h in flowing H₂, to form Ni₂P catalysts. The catalysts were characterized by H₂ temperature-programmed reduction (H₂-TPR), X-ray diffraction (XRD), N₂-adsorption specific surface area measurements (BET), CO uptake, transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). With sample of initial P/Ni molar ratio >0.5, the Ni₂P was successfully obtained at lower reduction temperature, and a high initial P/Ni molar ratio favors the formation of Ni₂P at lower temperature. Using less oxidic phosphorus precursor of hypophosphite enabled the Ni₂P to be formed at low reduction temperature. Evaluation of the activity for DBT HDS of the catalysts shows that the catalyst prepared with initial P/Ni ratios of 2 exhibited the highest activity. At a reaction temperature of 613 K, a pressure of 3.0 MPa, a H₂/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h^?1, the HDS conversion reached 99 % , and no catalyst deactivation was observed within 120 h.