Herein,we describe a case of robotic duodenum-preserving pancreatic head resection(DPPHR)performed on a 21-monthold male infant(weight:13 kg;body mass index:18.87 kg/m^(2))with focal nesidioblastosis,expanding the sco...Herein,we describe a case of robotic duodenum-preserving pancreatic head resection(DPPHR)performed on a 21-monthold male infant(weight:13 kg;body mass index:18.87 kg/m^(2))with focal nesidioblastosis,expanding the scope of minimally invasive pediatric hepatobiliary surgery(Fig.1;Video S1).Preoperative positron emission tomography-computed tomography revealed a 23×13 mm neuroendocrine lesion in the pancreatic head,which caused refractory hypoglycemia and necessitated surgical intervention.展开更多
The Zn-Al spinel oxide stands out as one of the most active catalysts for high-temperature methanol synthesis from CO_(2)hydrogenation.However,the structure–activity relationship of the reaction remains poorly unders...The Zn-Al spinel oxide stands out as one of the most active catalysts for high-temperature methanol synthesis from CO_(2)hydrogenation.However,the structure–activity relationship of the reaction remains poorly understood due to challenges in atomic-level structural characterizations and analysis of reaction intermediates.In this study,we prepared two Zn-Al spinel oxide catalysts via coprecipitation(ZnAl-C)and hydrothermal(ZnAl-H)methods,and conducted a comparative investigation in the CO_(2)hydrogenation reaction.Surprisingly,under similar conditions,ZnAl-C exhibited significantly higher selectivity towards methanol and DME compared to ZnAl-H.Comprehensive characterizations using X-ray diffraction(XRD),Raman spectroscopy and electron paramagnetic resonance(EPR)unveiled that ZnAl-C catalyst had abundant ZnO species on its surface,and the interaction between the ZnO species and its ZnAl spinel oxide matrix led to the formation of oxygen vacancies,which are crucial for CO_(2)adsorption and activation.Additionally,state-of-the-art solid-state nuclear magnetic resonance(NMR)techniques,including ex-situ and in-situ NMR analyses,confirmed that the surface ZnO facilitates the formation of unique highly reactive interfacial formate species,which was readily hydrogenated to methanol and DME.These insights elucidate the promotion effects of ZnO on the ZnAl spinel oxide in regulating active sites and reactive intermediates for CO_(2)-to-methanol hydrogenation reaction,which is further evidenced by the significant enhancement in methanol and DME selectivity observed upon loading ZnO onto the ZnAl-H catalyst.These molecular-level mechanism understandings reinforce the idea of optimizing the ZnO-ZnAl interface through tailored synthesis methods to achieve activity-selectivity balance.展开更多
As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of...As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of this unique species remains challenging.Recently,we have demonstrated that solid-state NMR can be an effective tool for studying surface Ga–H.In this work,we report a comparative solid-state NMR study on H_(2) activation over different Ga_(2)O_(3) polymorphs,specificallyα-,β-andγ-Ga_(2)O_(3).^(1)H solid-state NMR enabled the identification of Ga–H species formed on all the three samples following high-temperature H_(2) treatment.The characteristic ^(1)H NMR signals of Ga–H species are resolved using J-coupling-based double-resonance NMR methods,revealing highly similar lineshapes of Ga–H for all the Ga_(2)O_(3) samples.This suggests potentially similar surface Ga–H configurations among different Ga_(2)O_(3) polymorphs.In addition,the local hydrogen environments on the oxide surfaces are further explored using two-dimensional(2D)^(1)H–^(1)H homonuclear correlation spectra,revealing multiple spatially proximate Ga–H and Ga–H/–OH pairs on different Ga_(2)O_(3) polymorphs.These findings provide insights into the potential mechanism of H_(2) dissociation.Overall,this work offers new perspectives on the local structure of surface Ga–H on Ga_(2)O_(3),and the analytical approach presented here can be further extended to the study of other Ga-based catalysts and other metal hydride species.展开更多
Silicoaluminophosphate(SAPO)molecular sieves possess diverse architectures and exceptional high-temperature hydrothermal stability,rendering them important acid catalysts.However,enhancing acid concentration of certai...Silicoaluminophosphate(SAPO)molecular sieves possess diverse architectures and exceptional high-temperature hydrothermal stability,rendering them important acid catalysts.However,enhancing acid concentration of certain SAPO materials remains challenging,which limits their catalytic applications.Here,we report the synthesis of a series of SAPO materials using a developed SAPO precursor plus dual template(SPDT)strategy.A variety of SAPO materials characterized by high silica content and enhanced acidity,such as SAPO-34/56 intergrowths,SAPO-56,and SAPO-17,have been synthesized and thoroughly characterized using various techniques including integrated differential phase-contrast scanning transmission electron microscopy,two-dimensional solid-state nuclear magnetic resonance spectroscopy,and continuous rotation electron diffraction.The use of silica-enriched SAPO precursor combined with the flexible selection of the second template enables the crystalline phase regulation and improves the Si atoms incorporation into the framework.Notably,the synthesized SAPO-17 with abundant Si(4Al)species and unprecedentedly high acid density exhibits exceptional DeNO_(x)activity after Cu loading,with NO_(x)conversion exceeding 90%at 175–700℃.This outstanding performance can be attributed to the unique ERI structure and the increased acidity of SAPO-17.This work not only presents an effective method for synthesizing SAPO molecular sieves with enhanced acidity but also offers a new perspective for expanding the active temperature range of the ammonia selective catalytic reduction reaction.展开更多
文摘Herein,we describe a case of robotic duodenum-preserving pancreatic head resection(DPPHR)performed on a 21-monthold male infant(weight:13 kg;body mass index:18.87 kg/m^(2))with focal nesidioblastosis,expanding the scope of minimally invasive pediatric hepatobiliary surgery(Fig.1;Video S1).Preoperative positron emission tomography-computed tomography revealed a 23×13 mm neuroendocrine lesion in the pancreatic head,which caused refractory hypoglycemia and necessitated surgical intervention.
基金financially National Key R&D Program of China(No.2022YFA1504800)National Natural Science Foundation of China(Grant No.22325405,22372160,22321002)+1 种基金Liaoning Revitalization Talents Program(XLYC1807207)DICP I202104。
文摘The Zn-Al spinel oxide stands out as one of the most active catalysts for high-temperature methanol synthesis from CO_(2)hydrogenation.However,the structure–activity relationship of the reaction remains poorly understood due to challenges in atomic-level structural characterizations and analysis of reaction intermediates.In this study,we prepared two Zn-Al spinel oxide catalysts via coprecipitation(ZnAl-C)and hydrothermal(ZnAl-H)methods,and conducted a comparative investigation in the CO_(2)hydrogenation reaction.Surprisingly,under similar conditions,ZnAl-C exhibited significantly higher selectivity towards methanol and DME compared to ZnAl-H.Comprehensive characterizations using X-ray diffraction(XRD),Raman spectroscopy and electron paramagnetic resonance(EPR)unveiled that ZnAl-C catalyst had abundant ZnO species on its surface,and the interaction between the ZnO species and its ZnAl spinel oxide matrix led to the formation of oxygen vacancies,which are crucial for CO_(2)adsorption and activation.Additionally,state-of-the-art solid-state nuclear magnetic resonance(NMR)techniques,including ex-situ and in-situ NMR analyses,confirmed that the surface ZnO facilitates the formation of unique highly reactive interfacial formate species,which was readily hydrogenated to methanol and DME.These insights elucidate the promotion effects of ZnO on the ZnAl spinel oxide in regulating active sites and reactive intermediates for CO_(2)-to-methanol hydrogenation reaction,which is further evidenced by the significant enhancement in methanol and DME selectivity observed upon loading ZnO onto the ZnAl-H catalyst.These molecular-level mechanism understandings reinforce the idea of optimizing the ZnO-ZnAl interface through tailored synthesis methods to achieve activity-selectivity balance.
基金financially supported by the National Key R&D Program of China(No.2021YFA1502803)the National Natural Science Foundation of China(Nos.22325405,22372160,22432005 and 22321002)Dalian Science and Technology Talent Innovation Program(No.2024RG009).
文摘As a highly reactive reaction intermediate,surface gallium hydride(Ga–H)has garnered significant attention due to its critical role in various catalytic reactions.However,the detailed experimental characterization of this unique species remains challenging.Recently,we have demonstrated that solid-state NMR can be an effective tool for studying surface Ga–H.In this work,we report a comparative solid-state NMR study on H_(2) activation over different Ga_(2)O_(3) polymorphs,specificallyα-,β-andγ-Ga_(2)O_(3).^(1)H solid-state NMR enabled the identification of Ga–H species formed on all the three samples following high-temperature H_(2) treatment.The characteristic ^(1)H NMR signals of Ga–H species are resolved using J-coupling-based double-resonance NMR methods,revealing highly similar lineshapes of Ga–H for all the Ga_(2)O_(3) samples.This suggests potentially similar surface Ga–H configurations among different Ga_(2)O_(3) polymorphs.In addition,the local hydrogen environments on the oxide surfaces are further explored using two-dimensional(2D)^(1)H–^(1)H homonuclear correlation spectra,revealing multiple spatially proximate Ga–H and Ga–H/–OH pairs on different Ga_(2)O_(3) polymorphs.These findings provide insights into the potential mechanism of H_(2) dissociation.Overall,this work offers new perspectives on the local structure of surface Ga–H on Ga_(2)O_(3),and the analytical approach presented here can be further extended to the study of other Ga-based catalysts and other metal hydride species.
文摘Silicoaluminophosphate(SAPO)molecular sieves possess diverse architectures and exceptional high-temperature hydrothermal stability,rendering them important acid catalysts.However,enhancing acid concentration of certain SAPO materials remains challenging,which limits their catalytic applications.Here,we report the synthesis of a series of SAPO materials using a developed SAPO precursor plus dual template(SPDT)strategy.A variety of SAPO materials characterized by high silica content and enhanced acidity,such as SAPO-34/56 intergrowths,SAPO-56,and SAPO-17,have been synthesized and thoroughly characterized using various techniques including integrated differential phase-contrast scanning transmission electron microscopy,two-dimensional solid-state nuclear magnetic resonance spectroscopy,and continuous rotation electron diffraction.The use of silica-enriched SAPO precursor combined with the flexible selection of the second template enables the crystalline phase regulation and improves the Si atoms incorporation into the framework.Notably,the synthesized SAPO-17 with abundant Si(4Al)species and unprecedentedly high acid density exhibits exceptional DeNO_(x)activity after Cu loading,with NO_(x)conversion exceeding 90%at 175–700℃.This outstanding performance can be attributed to the unique ERI structure and the increased acidity of SAPO-17.This work not only presents an effective method for synthesizing SAPO molecular sieves with enhanced acidity but also offers a new perspective for expanding the active temperature range of the ammonia selective catalytic reduction reaction.
