Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion int...Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion into useful fuels.Herein,we provide a facile strategy for fabricating sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions(S-C_(3)N_(4)/SnO_(2)-SnS_(2))via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C_(3)N_(4).A hexagonal layered supramolecular structure was first prepared as the precursor of C_(3)N_(4).Then Sn^(4+) ions were intercalated into the supramolecular interlayers through the liquid impregnation method.The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C_(3)N_(4) porous nanosheets.Moreover,SnO_(2) nanoparticles were formed and embedded in situ in the porous C_(3)N_(4) nanosheets.In the following sulfidation process under a nitrogen atmosphere,sulfur powder can react with SnO_(2) nanoparticles to form SnO_(2)-SnS_(2) nanojunctions.As expected,the exfoliation of sulfur-doped C_(3)N_(4) porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work.Sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions featured abundant active sites,enhanced visible light absorption,and efficient interfacial charge transfer.As expected,the optimized S-C_(3)N_(4)/SnO_(2)-SnS_(2) achieved a much higher gas-phase photocatalytic CO_(2) reduction performance with high yields of CO(21.68μmol g^(−1)h^(−1))and CH_(4)(22.09μmol g^(−1)h^(−1))compared with the control C_(3)N_(4),C_(3)N_(4)/SnO_(2),and S-C_(3)N_(4)/SnS_(2) photocatalysts.The selectivity of CH_(4) reached 80.30%.Such a promising synthetic strategy can be expected to inspire the design of other robust C_(3)N_(4)-based porous nanosheet heterostructures for a broad range of applications.展开更多
目的:建立恩格列净片有关物质测定的HPLC法。方法:采用辛烷基硅烷键合硅胶为填充剂的色谱柱(ZORBAX Rx-C8,250 mm×4.6 mm,5μm),以p H 3.5的磷酸水溶液为流动相A,甲醇-乙腈(1∶1)为流动相B,梯度洗脱,流速1.0 m L·min^(-1),检...目的:建立恩格列净片有关物质测定的HPLC法。方法:采用辛烷基硅烷键合硅胶为填充剂的色谱柱(ZORBAX Rx-C8,250 mm×4.6 mm,5μm),以p H 3.5的磷酸水溶液为流动相A,甲醇-乙腈(1∶1)为流动相B,梯度洗脱,流速1.0 m L·min^(-1),检测波长224 nm,柱温为25℃,进样量20μL,对有关物质进行定性、定量分析。结果:在选定的色谱条件下,恩格列净与相邻杂质及各杂质之间的分离度均大于1.5;杂质IMPD(恩格列净还原产物)、杂质IMPC(恩格列净开环产物)、杂质EMGA(恩格列净中间体)、杂质IMPF(恩格列净缩合产物)、杂质IMPG(恩格列净脱葡萄糖醇产物)的定量限分别为28.30、53.07、73.60、65.00和395.57 ng,且在各自的线性范围内线性关系良好(r>0.999,n=5),平均回收率(n=9)分别为100.7%、102.9%、97.4%、102.1%和102.9%。对3批恩格列净片进行有关物质测定,结果总杂质量在0.05%～0.06%范围内。结论:经方法学验证,本法简便、灵敏,专属性好,可用于恩格列净片有关物质的测定。展开更多
基金supported by the National Natural Science Foundation of China(22072037 and 51772079)the Natural Science Foundation of Heilongjiang Province of China(LH2020B018)。
文摘Two-dimensional porous nanosheet heterostructure materials,which combine the advantages of both architecture and components,are expected to feature a significant photocatalytic performance toward CO_(2) conversion into useful fuels.Herein,we provide a facile strategy for fabricating sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions(S-C_(3)N_(4)/SnO_(2)-SnS_(2))via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C_(3)N_(4).A hexagonal layered supramolecular structure was first prepared as the precursor of C_(3)N_(4).Then Sn^(4+) ions were intercalated into the supramolecular interlayers through the liquid impregnation method.The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C_(3)N_(4) porous nanosheets.Moreover,SnO_(2) nanoparticles were formed and embedded in situ in the porous C_(3)N_(4) nanosheets.In the following sulfidation process under a nitrogen atmosphere,sulfur powder can react with SnO_(2) nanoparticles to form SnO_(2)-SnS_(2) nanojunctions.As expected,the exfoliation of sulfur-doped C_(3)N_(4) porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work.Sulfur-doped C_(3)N_(4) porous nanosheets with embedded SnO_(2)-SnS_(2) nanojunctions featured abundant active sites,enhanced visible light absorption,and efficient interfacial charge transfer.As expected,the optimized S-C_(3)N_(4)/SnO_(2)-SnS_(2) achieved a much higher gas-phase photocatalytic CO_(2) reduction performance with high yields of CO(21.68μmol g^(−1)h^(−1))and CH_(4)(22.09μmol g^(−1)h^(−1))compared with the control C_(3)N_(4),C_(3)N_(4)/SnO_(2),and S-C_(3)N_(4)/SnS_(2) photocatalysts.The selectivity of CH_(4) reached 80.30%.Such a promising synthetic strategy can be expected to inspire the design of other robust C_(3)N_(4)-based porous nanosheet heterostructures for a broad range of applications.
文摘目的:建立恩格列净片有关物质测定的HPLC法。方法:采用辛烷基硅烷键合硅胶为填充剂的色谱柱(ZORBAX Rx-C8,250 mm×4.6 mm,5μm),以p H 3.5的磷酸水溶液为流动相A,甲醇-乙腈(1∶1)为流动相B,梯度洗脱,流速1.0 m L·min^(-1),检测波长224 nm,柱温为25℃,进样量20μL,对有关物质进行定性、定量分析。结果:在选定的色谱条件下,恩格列净与相邻杂质及各杂质之间的分离度均大于1.5;杂质IMPD(恩格列净还原产物)、杂质IMPC(恩格列净开环产物)、杂质EMGA(恩格列净中间体)、杂质IMPF(恩格列净缩合产物)、杂质IMPG(恩格列净脱葡萄糖醇产物)的定量限分别为28.30、53.07、73.60、65.00和395.57 ng,且在各自的线性范围内线性关系良好(r>0.999,n=5),平均回收率(n=9)分别为100.7%、102.9%、97.4%、102.1%和102.9%。对3批恩格列净片进行有关物质测定,结果总杂质量在0.05%～0.06%范围内。结论:经方法学验证,本法简便、灵敏,专属性好,可用于恩格列净片有关物质的测定。
