Atomic ratio effect on catalytic performance of FeW-based carbides and nitrides on thiophene hydrodesulfurization Yanet Villasana a,⇑ , Franca Ruscio-Vanalesti a,b , Carolina Pfaff b , Franklin J. Méndez a , Miguel Ángel Luis-Luis c , Joaquín L. Brito a,⇑ a Centro de Química, Instituto Venezolano de Investigaciones Científicas, Apartado 20632, Caracas 1020-A, Venezuela b Facultad de Ingeniería, Universidad Central de Venezuela, Caracas 1020-A, Venezuela c Facultad Experimental de Ciencias y Tecnología, Universidad de Carabobo, Valencia, Venezuela highlights " New catalysts for HDS of thiophene based on FeW carbides and nitrides. " Alumina-supported FeW carbides and nitrides are synthesized by TPR method. " Thiophene HDS catalytic activity decreased with increasing atomic ratio Fe/(Fe + W). " Iron is not a good promoter to tungsten sulfides, carbides or nitrides. graphical abstract Initial Steady state Atomic Ratio (Fe/(Fe+W)) Atomic Ratio (Fe/(Fe+W)) C 4 H 4 S HDS activity C 4 H 4 S HDS activity Initial Steady state Atomic Ratio vs. C 4 H 4 S HDS activity 0 5 10 15 20 25 30 0 1 2 3 4 5 6 0.00 0.10 0.25 0.33 0.50 0.75 1.00 0.00 0.10 0.25 0.33 0.50 0.75 1.00 0,00 0,04 0,08 0,12 0,00 0,04 0,08 0,12 0.00 0.10 0.25 0.33 0.50 1.00 0.75 0.00 0.10 0.25 0.33 0.50 1.00 0.75 article info Article history: Received 30 March 2012 Received in revised form 2 November 2012 Accepted 8 November 2012 Available online 3 December 2012 Keywords: Nitrides Carbides FeW-catalyst Hydrodesulfurization abstract Synthesis of bulk and alumina-supported, Fe-promoted W carbides and nitrides were carried out by using oxidic precursors with atomic ratios (Fe/(Fe + W)) varying from 0 to 1. These materials were prepared by temperature-programmed reaction up to 700 °C of the precursors under flow of 20 vol.% CH 4 /H 2 , for car- bides, and of NH 3 for nitrides. Crystalline structure of catalysts was established by X-ray diffraction (XRD), while textural properties were determined by N 2 physisorption. Catalytic tests of thiophene hyd- rodesulfurization (HDS) were carried out in a fixed bed reactor at 400 °C and atmospheric pressure and monitored by FID-GC. The catalysts were activated in situ under a CS 2 /H 2 mixture at 300 °C/2 h prior to HDS. In addition, both fresh and exhausted catalysts were analyzed by elemental chemical analysis (ECA) of C, N and S. XRD results showed a main bimetallic phase Fe 2 WO 6 for supported oxidic precursors, while bulk catalysts revealed a mixture of Fe 2 WO 6 and FeWO 4 . On the other hand, for supported carbides, XRD revealed the presence of the cubic Fe 3 W 3 C mixed phase, and bulk carbides showed the presence of Fe 6 W 6 C. For supported nitrides, XRD data revealed the presence of the hexagonal FeWN 2 mixed phase for bimetallic catalysts and W 2.2 N 2 and Fe 3 N for each monometallic catalyst. In contrast, for bulk mono- metallic W nitride it was found that W 2 N was the monometallic crystalline phase obtained. Texture anal- ysis showed that specific surface area of catalyst decreased with respect to alumina, when Fe and W were incorporated and this effect increased with increasing Fe content. Catalytic tests revealed that the 0016-2361/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2012.11.055 ⇑ Corresponding authors. Tel.: +58 212 504 1321; fax: +58 212 504 1350. E-mail addresses: ytvillas@gmail.com (Y. Villasana), joabrito@ivic.gob.ve (J.L. Brito). Fuel 110 (2013) 259–267 Contents lists available at SciVerse ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel