As an important zeolite material,MFI zeolites,as well as their controllable synthesis,are of great interest in both basic and applied science.Among the developed synthetic approaches,the seed-induced method has gradua...As an important zeolite material,MFI zeolites,as well as their controllable synthesis,are of great interest in both basic and applied science.Among the developed synthetic approaches,the seed-induced method has gradually evolved into a facile,low-cost,and even green alternative to give zeolites the desirable physicochemical properties.In this review,we briefly summarize the development of seed-induced syntheses of diverse functional MFI zeolites,where the“living”seed crystals not only direct the formation of zeolitic framework but also function as special“templates”or“units”to fine-tune the zeolite materials with diverse sizes,shapes,compositions,morphologies and pore structures.Moreover,on the basis of their structural features and crystallization behaviors in seed-induced synthesis,we reveal the roles of seeds and discuss the related crystallization mechanisms including both classical and non-classical pathways.We also want to guide readers to investigate the structure-performance relationships between these functional MFI zeolite catalysts and suitable catalytic reactions.展开更多
The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly co...The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly conductive polymer and a prospective pseudocapacitive materials for supercapacitors,yet the inferior cyclic stability and unpredictable polymerization patterns severely impede its real-world applicability.Here,for the first time,an innovative seed-induced in-situ polymerization assisted 3D printing strategy is proposed to fabricate PPy-reduced graphene oxide/poly(vinylidene difluoride-cohexafluoropropylene)(PVDF-HFP)(PPy-rGO/PH)electrodes with controllable polymerization behavior and exceptional areal mass loading.The preferred active sites uniformly pre-planted on the 3D-printed graphene substrates serve as reliable seeds to induce efficient polypyrrole deposition,achieving an impressive mass loading of 185.6 mg cm^(-2)(particularly 79.2 mg cm^(-2)for polypyrrole)and a superior areal capacitance of 25.2 F cm^(-2)at 2 mA cm^(-2)for a 12-layer electrode.In agreement with theses appealing features,an unprecedented areal energy density of 1.47 mW h cm^(-2)for a symmetrical device is registered,a rarely achieved value for other PPy/rGO-based supercapacitors.This work highlights a promising route to preparing high energy density energy storage modules for real-world applications.展开更多
The catalytic performance of Mo supported on hierarchical alumina–silica(Si/Al = 15) with Mo loadings of 3, 6 and 15 wt% was investigated for the oxidative desulfurization(ODS) of model and real oil samples. Hierarch...The catalytic performance of Mo supported on hierarchical alumina–silica(Si/Al = 15) with Mo loadings of 3, 6 and 15 wt% was investigated for the oxidative desulfurization(ODS) of model and real oil samples. Hierarchical alumina–silica(h Al–Si) was synthesized by economical and ecofriendly silicate-1 seed-induced route using cetyltrimethylammonium bromide(CTAB) as mesoporogen. The effect of CTAB on the structure of catalyst was studied by characterization techniques. The results revealed that 6%Mo/h Al–Si had the highest sulfur removal compared to the other catalyst loadings. The effect of operating parameters was evaluated using Box–Behnken experimental design. The optimal desulfurization conditions with the 6%Mo/h Al–Si catalyst were determined at oxidation temperature of 67 ℃, oxidation time of 42 min, H2O2/S molar ratio of 8 and catalyst dosage of 0.008 g·ml^-1 for achieving a conversion of 95%. Under optimal conditions, different sulfur-containing compounds with initial concentration of 1000 ppm, Dibenzothiophene(DBT), Benzothiophene(BT) and Thiophen(Th), showed the catalytic oxidation reactivity in the order of DBT > BT>Th. According to the regeneration experiments, the 6%Mo/h Al–Si catalyst was reused 4 times with a little reduction in the performance. Also, the total sulfur content of gasoline and diesel after ODS process reached 156.6 and 4592.2 ppm, respectively.展开更多
High temperature physical vapor transport(HTPVT) was employed to grow polycrystalline SiC ceramics with high density and purity, induced by nano SiC particles as seeds. The obtained SiC ceramics were identified as 6 H...High temperature physical vapor transport(HTPVT) was employed to grow polycrystalline SiC ceramics with high density and purity, induced by nano SiC particles as seeds. The obtained SiC ceramics were identified as 6 H-SiC with a mainly preferred orientation along the(0 0 0 6) plane, and an obvious refinement of grain size was demonstrated for the SiC seeds. Mean grain sizes of the obtained SiC ceramics were112 μm and 314 μm, by using the SiC seeds with the mean particle size of 50 nm and 500 nm, respectively,which were obviously smaller than that of the seed-free sample(960 μm). The samples obtained with the seeds also demonstrated enhanced flexural strength and hardness, attributing to the reduced mean grain size. Furthermore, SiC ceramics without seeds via HTPVT exhibited a high thermal conductivity of242 W·(m·K)^-1 at room temperature due to the highly preferred orientation. While the degree of preferred orientation of seed-induced samples was lower, the thermal conductivity of SiC ceramics induced by seeding still maintained at least 200 W·(m·K)^-1 at room temperature, this level was much higher than most other methods. Therefore, seed-induced method appears to be an effective way to control structures and behavior of SiC ceramics through HTPVT.展开更多
基金the National Major Research and Development Plan(Grant No.2018YFA0209402)the National Natural Science Foundation of China(Grant Nos.21433022,21573046,21473037,U1463206 and 21802023)and Shanghai Sailing Program(No.18YF1401900).
文摘As an important zeolite material,MFI zeolites,as well as their controllable synthesis,are of great interest in both basic and applied science.Among the developed synthetic approaches,the seed-induced method has gradually evolved into a facile,low-cost,and even green alternative to give zeolites the desirable physicochemical properties.In this review,we briefly summarize the development of seed-induced syntheses of diverse functional MFI zeolites,where the“living”seed crystals not only direct the formation of zeolitic framework but also function as special“templates”or“units”to fine-tune the zeolite materials with diverse sizes,shapes,compositions,morphologies and pore structures.Moreover,on the basis of their structural features and crystallization behaviors in seed-induced synthesis,we reveal the roles of seeds and discuss the related crystallization mechanisms including both classical and non-classical pathways.We also want to guide readers to investigate the structure-performance relationships between these functional MFI zeolite catalysts and suitable catalytic reactions.
基金financially supported by the National Natural Science Foundation of China(No.51933007,No.52373047,No.52302106)the Sichuan Youth Science and Technology Innovation Research Team Project(No.2022JDTD0012)+2 种基金the Program for Featured Directions of Engineering Multidisciplines of Sichuan University(No.2020SCUNG203)the Natural Science Foundation of Sichuan Province(No.2023NSFSC0418)the Program for State Key Laboratory of Polymer Materials Engineering(No.sklpme2022-3-10)。
文摘The tireless pursuit of supercapacitors with high energy density entails the parallel advancement of wellsuited electrode materials and elaborately engineered architectures.Polypyrrole(PPy)emerges as an exceedingly conductive polymer and a prospective pseudocapacitive materials for supercapacitors,yet the inferior cyclic stability and unpredictable polymerization patterns severely impede its real-world applicability.Here,for the first time,an innovative seed-induced in-situ polymerization assisted 3D printing strategy is proposed to fabricate PPy-reduced graphene oxide/poly(vinylidene difluoride-cohexafluoropropylene)(PVDF-HFP)(PPy-rGO/PH)electrodes with controllable polymerization behavior and exceptional areal mass loading.The preferred active sites uniformly pre-planted on the 3D-printed graphene substrates serve as reliable seeds to induce efficient polypyrrole deposition,achieving an impressive mass loading of 185.6 mg cm^(-2)(particularly 79.2 mg cm^(-2)for polypyrrole)and a superior areal capacitance of 25.2 F cm^(-2)at 2 mA cm^(-2)for a 12-layer electrode.In agreement with theses appealing features,an unprecedented areal energy density of 1.47 mW h cm^(-2)for a symmetrical device is registered,a rarely achieved value for other PPy/rGO-based supercapacitors.This work highlights a promising route to preparing high energy density energy storage modules for real-world applications.
文摘The catalytic performance of Mo supported on hierarchical alumina–silica(Si/Al = 15) with Mo loadings of 3, 6 and 15 wt% was investigated for the oxidative desulfurization(ODS) of model and real oil samples. Hierarchical alumina–silica(h Al–Si) was synthesized by economical and ecofriendly silicate-1 seed-induced route using cetyltrimethylammonium bromide(CTAB) as mesoporogen. The effect of CTAB on the structure of catalyst was studied by characterization techniques. The results revealed that 6%Mo/h Al–Si had the highest sulfur removal compared to the other catalyst loadings. The effect of operating parameters was evaluated using Box–Behnken experimental design. The optimal desulfurization conditions with the 6%Mo/h Al–Si catalyst were determined at oxidation temperature of 67 ℃, oxidation time of 42 min, H2O2/S molar ratio of 8 and catalyst dosage of 0.008 g·ml^-1 for achieving a conversion of 95%. Under optimal conditions, different sulfur-containing compounds with initial concentration of 1000 ppm, Dibenzothiophene(DBT), Benzothiophene(BT) and Thiophen(Th), showed the catalytic oxidation reactivity in the order of DBT > BT>Th. According to the regeneration experiments, the 6%Mo/h Al–Si catalyst was reused 4 times with a little reduction in the performance. Also, the total sulfur content of gasoline and diesel after ODS process reached 156.6 and 4592.2 ppm, respectively.
基金supported by the National Natural Science Foundation of China (NSFC, grant No. 51672209)the National Key R&D Program of China (Grant No. 2017YFB0310300)the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2016JQ5046)
文摘High temperature physical vapor transport(HTPVT) was employed to grow polycrystalline SiC ceramics with high density and purity, induced by nano SiC particles as seeds. The obtained SiC ceramics were identified as 6 H-SiC with a mainly preferred orientation along the(0 0 0 6) plane, and an obvious refinement of grain size was demonstrated for the SiC seeds. Mean grain sizes of the obtained SiC ceramics were112 μm and 314 μm, by using the SiC seeds with the mean particle size of 50 nm and 500 nm, respectively,which were obviously smaller than that of the seed-free sample(960 μm). The samples obtained with the seeds also demonstrated enhanced flexural strength and hardness, attributing to the reduced mean grain size. Furthermore, SiC ceramics without seeds via HTPVT exhibited a high thermal conductivity of242 W·(m·K)^-1 at room temperature due to the highly preferred orientation. While the degree of preferred orientation of seed-induced samples was lower, the thermal conductivity of SiC ceramics induced by seeding still maintained at least 200 W·(m·K)^-1 at room temperature, this level was much higher than most other methods. Therefore, seed-induced method appears to be an effective way to control structures and behavior of SiC ceramics through HTPVT.