To increase the dispersion of active species and full utilization of active metals are of great importance for hydrodenitrogenation (HDN) performance of unsupported hydrotreating catalysts. Herein, a series of unsupported Ni(Zr)MoS and Ni(Zr)WS catalysts were prepared from Ni(Zr) layered double hydroxide (LDH) precursors. The Zr species remarkably promote the dispersion and reducibility of NiMo and NiW composite species. Also, the total HDN rate constants are increased from 2.42 h⁻¹ to 9.18 h⁻¹ for Ni(Zr)MoS and from 5.68 h⁻¹ to 23.0 h⁻¹ for Ni(Zr)WS, and exhibit a maximum at a Zr/Ni atomic ratio of about 0.04. The HDN selectivities indicate that the Zr species increase the number of superficial active sites without affecting their structure. The present work shows that the crystallinity of LDH precursors is crucial to the structure of unsupported sulfide catalysts, and a suitable amount of Zr could be a dispersive promoter to increase the HDN activity.

提高活性物质的分散性和充分利用活性金属对于无载体加氢处理催化剂的加氢脱氮（HDN）性能至关重要。本文中，由Ni（Zr）层状双氢氧化物（LDH）前驱体制备了一系列无载体的Ni（Zr）MoS和Ni（Zr）WS催化剂。Zr物种显着促进NiMo和NiW复合物种的分散和还原性。另外，Ni（Zr）MoS的总HDN速率常数从2.42 h ^-1增加到9.18 h ^-1，从5.68 h ^-1增加到23.0 h ^-1对于Ni（Zr）WS而言，其在Zr / Ni原子比约为0.04时显示出最大值。HDN的选择性表明Zr物种增加了表面活性位点的数量，而不影响其结构。目前的工作表明，LDH前体的结晶度对于无载体硫化物催化剂的结构至关重要，并且适量的Zr可能是提高HDN活性的分散促进剂。