The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube （CNT） was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were i...The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube （CNT） was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization （HDS） performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% （percent by mass, based on MoO3）. TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.展开更多
Eleven new species of Ourapteryx Leach,1814 were described:O.curta Jiang&Han,sp.nov.,O.triangulata Cheng&Han,sp.nov.,O.cawarongensis Cheng&Jiang,sp.nov.,O.arcuata Jiang&Cheng,sp.nov.,O.longiacutata Jia...Eleven new species of Ourapteryx Leach,1814 were described:O.curta Jiang&Han,sp.nov.,O.triangulata Cheng&Han,sp.nov.,O.cawarongensis Cheng&Jiang,sp.nov.,O.arcuata Jiang&Cheng,sp.nov.,O.longiacutata Jiang&Cheng,sp.nov.,O.linzhiensis Jiang&Cheng,sp.nov.,O.aniqiaoensis Cheng&Zhu,sp.nov.,O.incurvata Cheng&Jiang,sp.nov.,O.concava Cheng&Han,sp.nov.,O.alba Cheng&Han,sp.nov.,O.motuoensis Cheng&Zhu,sp.nov.Diagnoses for these new species are provided,with illustrations of external features and genitalia.展开更多
Near-infrared(NIR)chiroptical response has been less explored because it is chal-lenging to achieve both chirality and NIR absorption/emission.Herein,we describe the design of heterohelicene-typeβ-isoindigo-based bor...Near-infrared(NIR)chiroptical response has been less explored because it is chal-lenging to achieve both chirality and NIR absorption/emission.Herein,we describe the design of heterohelicene-typeβ-isoindigo-based boron-dipyrromethene(BOD-IPY)analogs(β-IBs),which shift the absorption peak to 800 nm and produce significant Cotton effects(127.8 M-1 cm-1)and absorbance dissymmetry factors(|gabs|3.5=×10-3).The luminescence dissymmetry factor(glum)and circu-larly polarized luminescence(CPL)brightness(BCPL)of up to 1.24×10-3 and 1.78 M-1 cm-1 were realized beyond 800 nm.Theseβ-IBs are thefirst examples of helicene-type compounds with the highest gabs in the NIR region and CPL beyond 800 nm.Theoretical calculations demonstrate that the strong chiroptical activities are triggered by their large transition magnetic dipole moments.This study not only provides a new approach to the synthesis of a larger variety of unprecedented helicene-type BODIPY analogs but also demonstrates excellent NIR chiroptical properties.展开更多
文摘The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube （CNT） was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization （HDS） performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% （percent by mass, based on MoO3）. TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.
基金supported by grants from the survey of Wildlife Resources in Key Areas of Xizang(ZL202203601)the National Nature Science Foundation of China(32170464)+3 种基金Biological Resources Programme of Chinese Academy of Sciences(KFJ-BRP-017-45)the National Science&Technology Fundamental Resources Investigation Program of China(2019FY101800)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0501)the base line survey on diversity of pollinating insects in Qomolangma National Nature Reserve。
文摘Eleven new species of Ourapteryx Leach,1814 were described:O.curta Jiang&Han,sp.nov.,O.triangulata Cheng&Han,sp.nov.,O.cawarongensis Cheng&Jiang,sp.nov.,O.arcuata Jiang&Cheng,sp.nov.,O.longiacutata Jiang&Cheng,sp.nov.,O.linzhiensis Jiang&Cheng,sp.nov.,O.aniqiaoensis Cheng&Zhu,sp.nov.,O.incurvata Cheng&Jiang,sp.nov.,O.concava Cheng&Han,sp.nov.,O.alba Cheng&Han,sp.nov.,O.motuoensis Cheng&Zhu,sp.nov.Diagnoses for these new species are provided,with illustrations of external features and genitalia.
基金National Natural Science Foundation of China,Grant/Award Numbers:21871072,22003014Hangzhou Normal University。
文摘Near-infrared(NIR)chiroptical response has been less explored because it is chal-lenging to achieve both chirality and NIR absorption/emission.Herein,we describe the design of heterohelicene-typeβ-isoindigo-based boron-dipyrromethene(BOD-IPY)analogs(β-IBs),which shift the absorption peak to 800 nm and produce significant Cotton effects(127.8 M-1 cm-1)and absorbance dissymmetry factors(|gabs|3.5=×10-3).The luminescence dissymmetry factor(glum)and circu-larly polarized luminescence(CPL)brightness(BCPL)of up to 1.24×10-3 and 1.78 M-1 cm-1 were realized beyond 800 nm.Theseβ-IBs are thefirst examples of helicene-type compounds with the highest gabs in the NIR region and CPL beyond 800 nm.Theoretical calculations demonstrate that the strong chiroptical activities are triggered by their large transition magnetic dipole moments.This study not only provides a new approach to the synthesis of a larger variety of unprecedented helicene-type BODIPY analogs but also demonstrates excellent NIR chiroptical properties.
