Hierarchization of Mordenite as NiW Sulfide Catalysts Support: Towards Efficient Hydrodesulfurization Yi Wang, [a, b] Christine Lancelot,* [b] Carole Lamonier, [b] FrØdØric Richard, [c] Kunyue Leng, [a] Yinyong Sun,* [a] and Alain Rives [b] Introduction As one important refinery process, hydrodesulfurization (HDS) of transportation fuels received much attention in recent years. Owing to the stringent demand of the environmental regula- tions, the sulfur level in fuels must be reduced to 10 ppm in many countries. [1–3] However, owing to the presence of refrac- tory sulfur-containing molecules such as 4,6-dimethyldibenzo- thiophene (4,6-DMDBT), deep desulfurization of diesel fuels is difficult to achieve because of the effect of steric hindrance from the alkyl groups adjacent to the sulfur atom. [4–9] There- fore, the design and development of highly efficient HDS cata- lysts that can eliminate the effect of steric hindrance have been pursued. The commercial catalysts are usually composed of molybde- num disulfide promoted by Co or Ni atoms and supported on alumina. The utilization of acidic supports has been suggested to improve catalytic performance. One explanation is that they enable dealkylation and isomerization of the alkyl substituents so that the effect of steric hindrance may be relieved. [9–12] The enhancement of activity was also related to the electron-defi- cient character of the sulfide particles, owing to electronic transfer between the acidic zeolite and the active-phase parti- cles. [13] Additionally, it was also proposed that the interaction of active phases with acidic supports could be weakened and thus the sulfidation degree of active phases may be im- proved. [14] Based on these reasons, zeolites with strong acidity have been selected as supports of HDS catalysts. [15] However, owing to their relatively small pore size, several problems such as rapid deactivation [7, 14] and diffusion limitation [16] were gener- ally observed. To remedy the disadvantage of microporous zeolites, hier- archical zeolites were developed and have attracted much at- tention because of the introduction of additional meso- pores. [17–20] Several studies present their use as supports for HDS catalysts. For example, noble-metal catalysts were sup- ported on mesoporous zeolites such as ZSM-5, [21] Beta, [22] and Y [23] for the HDS of 4,6-DMDBT. The results indicated that these catalysts exhibited higher efficiency in desulfurization than those on alumina or mesoporous silica. CoMoS sulfide phases were supported on several mesoporous materials as a zeolite L, [16, 24, 25] ZSM-5, [26] beta, [27] and mordenite (MOR), [28] allowing to improve their activity in the HDS of FCC gasoline, DBT, and 4,6- DMDBT, compared to those obtained on catalysts supported on conventional zeolites. On the other hand, it is well known that nitrogen-containing and aromatic compounds in fuels would inhibit the HDS activi- ty of catalysts. [29–31] Therefore, catalyst with good ability of HDS, hydrodenitrogenation (HDN), and hydrodearomatization (HDA) is required. Among the studied HDS catalysts, NiW cata- lysts have better hydrogenation properties than NiMo catalysts and have displayed superior catalytic activity in the HDA and HDN reactions. [32] For this reason the use of NiW supported on NiW-based catalysts were supported on Al 2 O 3 , commercial mordenite (HM), and hierarchical mordenite prepared by acid– base–acid treatment (HM–M). Their catalytic performance was evaluated in the hydrodesulfurization (HDS) of dibenzothio- phene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) at 613 K under 4 MPa as total pressure. In the HDS of DBT, NiW/Al 2 O 3 exhibited better catalytic activity than NiW/HM and NiW/HM–M. On the contrary, NiW/HM–M exhibited the highest catalytic performance in the HDS of 4,6-DMDBT, attributed to different factors: an improved dispersion of the active phase, a better accessibility to the active sites owing to the creation of mesoporosity, and an additional reaction route (isomeriza- tion) owing to the acidic properties of the zeolitic support. These results show the potential interest of hierarchical mor- denite as support for HDS catalysts, with the presence of mesoporosity beneficial to the HDS of large and refractory molecules. [a] Y. Wang, K. Leng, Prof. Y. Sun School of Chemical Engineering and Technology Harbin Institute of Technology Harbin 150001 (P.R. China) E-mail : yysun@hit.edu.cn [b] Y. Wang, Dr. C. Lancelot, Prof. C. Lamonier, Dr. A. Rives UnitØ de Catalyse et de Chimie du Solide, UMR CNRS 8181 UniversitØ Lille 59655 Villeneuve d’Ascq (France) E-mail : christine.lancelot@univ-lille1.fr [c] Dr. F. Richard Institut de Catalyse des Milieux et MatØriaux de Poitiers, UMR CNRS 7285 UniversitØ de Poitiers 86073 Poitiers Cedex 9 (France) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cctc.201500686. ChemCatChem 2015, 7, 3936 – 3944 # 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 3936 Full Papers DOI: 10.1002/cctc.201500686