Plate-like MFI zeolite with a short b-axis length is highly desired for industrial applications,because the larger straight channels along the b-axis are a primary pathway for mass transfer.This work reports that guan...Plate-like MFI zeolite with a short b-axis length is highly desired for industrial applications,because the larger straight channels along the b-axis are a primary pathway for mass transfer.This work reports that guanidine compounds,such as tetramethylguanidine(TMG),dodecylguanidine hydrochloride(DGH),and polyhexamethylene biguanidine hydrochloride(PHMB),are more efficient for synthesizing these types of zeolites,needing neither a greater amount of water nor a longer crystallization period.Because of the modifiers used,the zeolite crystals with a thickness of 75–110 nm were obtained by crystallizing the gel with an H_(2)O/SiO_(2) mole ratio of 14 at 170℃ for 12 h.Moreover,the incorporation of Al and Ti into the ZSM-5 and TS-1 frameworks was also increased by the modifiers.展开更多
In this work, the Pd-based catalysts were designed via immobilizing Pd nanoparticles on graphite oxide (GO) modified with organic base, 1,1,3,3-tetramethylguanidine (TMG), which was used for the selective hydrogenatio...In this work, the Pd-based catalysts were designed via immobilizing Pd nanoparticles on graphite oxide (GO) modified with organic base, 1,1,3,3-tetramethylguanidine (TMG), which was used for the selective hydrogenation of citral. These catalysts were characterized by various techniques including IR, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was demonstrated that the Pd particles with size less than 5 nm were uniformly distributed throughout the support, and they were in the electron-deficient state due to the strong interactions with the modified support. The resultant Pd-TMG/GO catalyst displayed high efficiency for the selective hydrogenation of citral with a turnover frequency of 7100 h-1 as well as superior selectivity to citronellal of 89.6%. Moreover, the catalyst can be reused for five times without obvious activity loss, which may result from its stable structure.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.22076017).
文摘Plate-like MFI zeolite with a short b-axis length is highly desired for industrial applications,because the larger straight channels along the b-axis are a primary pathway for mass transfer.This work reports that guanidine compounds,such as tetramethylguanidine(TMG),dodecylguanidine hydrochloride(DGH),and polyhexamethylene biguanidine hydrochloride(PHMB),are more efficient for synthesizing these types of zeolites,needing neither a greater amount of water nor a longer crystallization period.Because of the modifiers used,the zeolite crystals with a thickness of 75–110 nm were obtained by crystallizing the gel with an H_(2)O/SiO_(2) mole ratio of 14 at 170℃ for 12 h.Moreover,the incorporation of Al and Ti into the ZSM-5 and TS-1 frameworks was also increased by the modifiers.
基金financially supported by the National Natural Science Foundation of China (20903105, 21073202)Chinese Academy of Sciences (KJXC2.YW.H30)
文摘In this work, the Pd-based catalysts were designed via immobilizing Pd nanoparticles on graphite oxide (GO) modified with organic base, 1,1,3,3-tetramethylguanidine (TMG), which was used for the selective hydrogenation of citral. These catalysts were characterized by various techniques including IR, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was demonstrated that the Pd particles with size less than 5 nm were uniformly distributed throughout the support, and they were in the electron-deficient state due to the strong interactions with the modified support. The resultant Pd-TMG/GO catalyst displayed high efficiency for the selective hydrogenation of citral with a turnover frequency of 7100 h-1 as well as superior selectivity to citronellal of 89.6%. Moreover, the catalyst can be reused for five times without obvious activity loss, which may result from its stable structure.
