In this paper NiW/γ-Al₂O₃catalysts were prepared by consecutive impregnation of a W/γ-Al₂O₃ catalyst with an aqueous solution of nickel salt. The structural control of the nickel ion precursor in the impregnation solution was achieved by the addition of 1, 2-cyclohexanediamine-N, N, N’, N’-tetraacetic acid (CyDTA) as a chelating agent at different pH. The influence of the sulfidation pressure (1 bar vs 40 bar) on the activity and structure of the NiW catalysts was investigated. The catalysts performances were tested in hydrodesulfurization (HDS) of thiophene after sulfidation at atmospheric or high pressure. The catalysts were characterized by X-Ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) and infrared spectroscopy of adsorbed CO (IR/CO) to explain the modification in surface species composition due to the chelating agent CyDTA and sulfiding conditions.

NiW catalysts prepared in presence of CydTA and sulfided under high pressure displayed the highest HDS activity. These two factors enhanced the sulfidation degree of W-based species as characterized by XPS. A linear correlation was found between the HDS activity and the sulfidation degree. In addition, chelating agent addition induced a decrease on metal-support interaction, as pointed out by TPR, and strongly favored the creation of CUS sites on the NiWS phase as seen by IR/CO. All these features favored a high catalytic activity. In addition, high pressure sulfidation not only leads to more active NiW catalysts but improved the butene-over-butane ratio.

本文通过连续浸渍 W/γ-Al ₂ O ₃制备NiW/γ-Al ₂ O ₃催化剂。用镍盐水溶液作为催化剂。浸渍溶液中镍离子前驱体的结构控制是通过添加 1, 2-环己二胺-N, N, N', N'-四乙酸 (CyDTA) 作为螯合剂在不同 pH 下实现的。研究了硫化压力（1 bar 对 40 bar）对 NiW 催化剂活性和结构的影响。在常压或高压下硫化后的噻吩加氢脱硫（HDS）中测试了催化剂的性能。催化剂通过 X 射线光电子能谱 (XPS)、程序升温还原 (TPR) 和吸附 CO 的红外光谱 (IR/CO) 进行表征，以解释由于螯合剂 CyDTA 和硫化条件导致的表面物种组成的改变。

在 CydTA 存在下制备并在高压下硫化的 NiW 催化剂显示出最高的 HDS 活性。这两个因素增强了 XPS 表征的 W 基物种的硫化程度。在 HDS 活性和硫化度之间发现线性相关性。此外，正如 TPR 所指出的，螯合剂的添加会导致金属-载体相互作用的减少，并且强烈有利于在 NiWS 相上创建 CUS 位点，如 IR/CO 所见。所有这些特征都有利于高催化活性。此外，高压硫化不仅导致 NiW 催化剂活性更高，而且提高了丁烯与丁烷的比例。