WxC/SBA-16催化剂的制备、表征及催化加氢脱硫性能

以正硅酸乙酯为硅源, 仲钨酸铵为钨源, P123和F127为混合模板剂,采用水热晶化法一步合成了不同钨含量(以n(Si):n(W)表示)的WO3/SBA-16, 然后经甲烷/氢气(V(CH4)/V(H2)=1/4)混和气体程序升温还原碳化(TPC), 制备出了WxC/SBA-16(x=1, 2)催化剂. 采用XRD、N2-吸附/脱附、TEM和FTIR等分析测试技术对样品的结构进行了表征, 并以噻吩作为模型化合物, 对WxC/SBA-16催化剂的加氢脱硫催化活性进行了评价. 结果表明, 在一定钨含量的条件下, WO3/SBA-16和WxC/SBA-16样品仍然保持立方笼状介孔结构, 当n(Si):n(W)为30-10时, 碳化钨的物相为W2C; n(Si):n(W)为7.5时, 碳化钨的物相为W2C和WC. WxC/SBA-16催化剂表现出了良好的加氢脱硫催化性能.

Preparation, Characterization and Catalytic Performance for Hydrodesulfurization of WxC/SBA-16 Catalysts

A series of WO3/SBA-16 samples with different W contents were synthesized under hydrothermal conditions using tetraethyl orthosilicate (TEOS) as silica source, ammonium paratungstate as tungsten source, and the mixture of F127 (EO106PO70EP106) and P123 (EO20PO70EP20) as template in strong acidic medium. The correspondingWxC/SBA-16 (x=1, 2) catalysts were prepared by the temperature-programmed carburization (TPC) method using CH4/H2 mixture gases (V(CH4)/V(H2)=1/4) from their oxide precursors. The structures of the samples were characterized by XRD, N2 adsorption/desorption isotherms, TEM, and FTIR. The catalytic performance of the WxC/SBA-16 (x=1, 2) catalysts for the hydrodesulfurization (HDS) of thiophene was evaluated in a continuous-flow fixed-bed quartz reactor. The results indicated that all samples maintained well cage-like structure of SBA-16 mesoporous molecular sieve with a cubic symmetry. In the tungsten carbide catalysts, the tungsten carbide was the W2C phase when n(Si)/n(W) was from 30 to 10. However, the tungsten carbides were a mixture of W2C and WC phases when n(Si)/n(W) was 7.5. The tungsten carbide catalysts exhibited good catalytic activity for HDS of thiophene.