Published: June 15, 2010 r2010 American Chemical Society 2530 dx.doi.org/10.1021/ie100574w | Ind. Eng. Chem. Res. 2011, 50, 2530–2535 ARTICLE pubs.acs.org/IECR Synthesis, Characterization, and Thiophene Hydrodesulfurization Activity of Novel Macroporous and Mesomacroporous Carbon Murid Hussain,* ,†,‡ Ji Sun Yun, † Son-Ki Ihm, † Nunzio Russo, ‡ and Francesco Geobaldo ‡ † National Research Laboratory for Environmental Catalysis, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Gusung-dong, Yusung-gu, Daejeon 305-701, South Korea ‡ Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy ABSTRACT: Two different types of macroporous and mesomacroporous carbons have been synthesized using the templating method with polystyrene (PS) and SBA-15/PS (1:4) as templates. These synthesized carbon materials were exact replicas of the templates and showed a small window in the large pores of macroporous carbon in addition to mesophase in mesomacroporous carbon. Materials were characterized using X-ray diffraction (XRD), nitrogen adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FT-IR), and CO chemisorption. Mo, Co, and CoMo catalysts were prepared by supporting the aforementioned metals on optimized macroporous and mesomacroporous carbon, while commercial activated carbon (Darco G-60) and alumina (γ-Al2O3) supported catalysts were used for comparison purposes. Thiophene hydrodesulfurization of these catalysts showed that mesomacroporous carbon supported catalysts had superior activity and selectivity compared to the others, which might be due to its better metal dispersion and bimodal porosity which made transport easier and minimized channel blocking. 1. INTRODUCTION One of the most urgent aims in the petroleum industry is the development of highly active hydrodesulfurization (HDS) cata- lysts, not only to protect the environment but also to efficiently utilize limited natural resources. 1,2 The sulfides of transition metals (Mo, W, Co, or Ni) are currently of great industrial interest as catalysts in petroleum refining for hydroprocessing applications such as HDS. 3 These metals have been mostly used for HDS catalysis, and no alternative to them has been reported to date. The catalytic activities of Mo, Co, and Co-Mo sulfide catalysts for HDS are influenced to a great extent by the support employed. Alumina is the most widely used support for hydro- treating catalysts. However, a strong interaction between metal and alumina is undesirable, as it leads to a negative effect on the HDS activity. The quest for a superior support system that avoids the main disadvantages of alumina has led researchers to explore alternative support materials. 4 Carbon and silica are the most suitable alternatives to the alumina support. Carbon in particular seems to be very promising as a catalytic support material and has received a great deal of attention as a support for HDS catalysts since high HDS activities have been reported that may originate from a more favorable support/catalytic species interaction. 2,5-7 Porous materials have long been studied and have been applied to commercial processes in various fields, such as in catalysis, adsorp- tion, absorption, and separation because of their attractive material properties. 8-12 Mesoporous carbon as well as mesoporous silica have already been studied in depth by researchers 4,13-16 for HDS applica- tions. These materials show better performances than commercial alumina or activated carbon. The surface area, porosity, and surface chemistry play key roles in this context. However, in this investigation, we have focused on the study of the novel macroporous carbon (MC) with small open windows and mesomacroporous carbon (MMC) for HDS application. These replica carbons were obtained by templating polystyrene (PS) and SBA-15/PS, respectively. The HDS activities of macro- porous and mesomacroporous carbon based Mo, Co, and CoMo catalysts have been compared with commercial activated carbon (AC) and γ-Al 2 O 3 based catalysts to investigate the effect of the characteristics of the supports on the catalytic activity and on product selectivity. 2. EXPERIMENTAL SECTION 2.1. Synthesis of the Support Materials. MC and MMC were synthesized by the templating method 14 using sucrose as a carbon precursor. PS and SBA-15/PS were used as the templates for the synthesis of the MC and MMC, respectively. SBA-15 meso- phase, PS beads, and SBA-15/PS were synthesized according to the procedure reported in Ihm et al., 17 but a different SBA-15/PS1 ratio of 1:4 was adopted. Carbon precursor solution impregnation was used 1 and 2 times to make MC1,2 and MMC1,2. After carboniza- tion in a furnace at 900 °C under vacuum, the silica template source SBA-15 was removed by dissolving with 5 wt % hydrofluoric acid (HF: 48-51%, J.T. Baker). PS was evaporated at a high carboniza- tion temperature. Finally, the MC and MMC were dried at 100 °C. AC (Darco G-60) and γ-alumina were purchased from Norit and Strem Chemicals, respectively. 2.2. Catalyst Preparations. Equal numbers of metal atoms of Mo (6.8 wt %) and Co (4.2 wt %) were loaded on MC2, MMC2, AC, and alumina with ammonium heptamolybdate tetrahydrate (Aldrich) and cobalt nitrate tetrahydrate (Aldrich) by incipient wetness. In the CoMo catalysts, a Co/Mo ratio of 5:5 was fixed Special Issue: IMCCRE 2010 Received: March 10, 2010 Accepted: June 2, 2010 Revised: June 1, 2010