摘要：Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic ***,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene *** is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon *** FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V *** reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V *** in acidic media,*** thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial *** interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR *** study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.

摘要：目的基于ITS序列用PCR-RFLP方法鉴别北柴胡药材掺伪藏柴胡的方法。方法分析并筛选出藏柴胡特有的限制性内切酶AseⅠ,用Primer Premier 5.0设计特异性引物,对引物PCR扩增条件和酶切试验进行优化,并对该方法的准确性进行了考察。结果PCR扩增的目的片段为331 bp,且建立的PCR反应方法对不同的酶均具有适应性。限制性内切酶AseⅠ将藏柴胡切成79 bp和252 bp两个片段,而北柴胡及其他柴胡均不能被酶切,且掺伪检出限为1%。结论PCR-RFLP方法实现了准确鉴别北柴胡中的混伪品藏柴胡。