Ni2P的制备及其含磷杂质对其催化DBT加氢脱硫性能的影响

分别以次磷酸(H3PO2)和氢氧化镍为磷源和镍源，采用低温H2等离子体还原法制备体相Ni2P，并研究其在加氢脱硫反应(HDS)中的催化性能。考察了等离子体电源输入电压的升高速率、还原气体(H2)流速、还原终电压和还原时间等因素对Ni2P的形成及其HDS催化性能的影响。采用X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)和电感耦合等离子体发射光谱(ICP-AES)等手段对所制备的Ni2P样品进行分析表征，以二苯并噻吩(DBT)的十氢萘溶液(质量分数0.8%)为原料评价了Ni2P催化剂的HDS活性。结果表明，以H3PO2为磷源制备Ni2P过程中，H2等离子体还原条件控制对Ni2P单一晶相的形成非常重要。在非最佳还原条件下，所制备的Ni2P样品中会出现Ni2P4O12?10H2O、H3PO4和Ni(PO3)2等含磷杂质，这些杂质会抑制Ni2P的HDS活性。水洗可除去Ni2P中部分含磷杂质，催化剂的反应活性提高不明显；氨水洗涤可有效除去大部分含磷杂质，Ni2P催化剂的反应活性会有明显的提高。因此，Ni2P催化剂合成过程中形成的含磷杂质是影响其催化性能的一个重要因素，选择适宜的制备条件抑制含磷杂质的生成有助于增强催化性能。

Preparation of Ni2P and Effect of Phosphorus-Containing Impurities on DBT Hydrodesulfurization Performance

Bulk Ni2P was prepared by low temperature hydrogen plasma from oxide precursors with hypophosphorous acid as phosphorus source and nickel hydroxide as nickel source. Catalytic performance of the prepared Ni2P was tested with hydrodesulfurization (HDS) reactions. Effects of ramping rate of generator voltage, flow rate of reducing gas (H2), final reduction voltage, and reduction time on Ni2P preparation and its HDS performance were investigated. In addition, the prepared catalysts were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma optical emission spectroscopy (ICP-AES). Catalytic performance of the prepared catalyst in HDS was evaluated with dibenzothiophene (0.8%, in decalin solution) as a model compound. It is found that the hydrogen plasma reduction conditions are critical important in preparing Ni2P crystal phase when H3PO2 is used as phosphorus source. Phosphorous-containing impurities, such as Ni2P4O12?10H2O、H3PO4, and , could appear in Ni2P under unfavorable reduction conditions. These impurities can inhibit HDS activity of Ni2P. The phosphorus-containing impurities can be partically removed by water washing, but it can only improve the reaction activity slightly. Most phosphorus-containg impurites can be removed by aqueous ammonia washing, which can impurities and hence can improve reaction activity significantly. A proper preparation method, which can inhibit the formation of phosphorus-containing impurities, can significantly improve catalyst performance of Ni2P.