燃料电池作为一种清洁、高效的能量转换装置,其大规模应用受到阴极氧还原反应(ORR)动力学缓慢以及铂资源稀缺和价格高昂等的极大制约.尽管研究人员在过去几十年中付出了巨大努力,但研制高效、耐用的低Pt合金催化剂仍亟待突破.近年的研...燃料电池作为一种清洁、高效的能量转换装置,其大规模应用受到阴极氧还原反应(ORR)动力学缓慢以及铂资源稀缺和价格高昂等的极大制约.尽管研究人员在过去几十年中付出了巨大努力,但研制高效、耐用的低Pt合金催化剂仍亟待突破.近年的研究表明,Pt的一些高指数晶面能够表现出比Pt(111)晶面更高的ORR活性,尤其是Pt(332),Pt(331)和Pt(554)等.同时,合金化能够通过电子与几何效应减弱含氧物种在Pt表面的吸附能,提升Pt合金催化剂的ORR活性.因此,高指数晶面和合金化的结合将是设计开发高性能电催化剂的有效手段.本文提出一种气氛调控的液相合成方法,通过在油胺中加热还原Pt化合物和Cu化合物,不添加其它保护剂,仅通过反应气氛的调控,成功制备了不同形貌的Pt-Cu合金纳米结构(纳米多脚、纳米凹立方体、纳米枝晶).通过反应前期引入氧化性气氛随后切换为惰性气氛的调控策略,合成具有高指数晶面的具有纳米枝晶结构的PtCu3合金;进一步对其进行电化学去合金化形成富Pt壳层,既保持其纳米枝晶形貌和高指数晶面,又形成具有梯度组成的PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶.相比而言,全程惰性气氛下生长得到纳米多脚结构,全程氧化性气氛下生长则得到纳米凹立方体.电化学测试结果表明,在0.1 M HClO4电解液中,PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶展现出较高的ORR活性,在0.9 V(vs.RHE)处的Pt质量活性和面积活性高达1.55 A mgPt^(-1)和2.4 mA cmPt^(-2),分别为商业Pt/C催化剂的14倍和24倍;此外,PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶具有良好的电化学稳定性能,经0.7~1.1 V(vs.RHE)电势范围内循环5000圈,其催化活性保持稳定.DFT计算表明,Cu合金效应和高指数晶面结构共同增强了Pt的ORR活性,其中PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶高指数晶面台阶位点的氧结合能接近最优值,从而表现出火山顶点附近的ORR活性.展开更多
To the Editor:Glioma is a highly invasive and lethal heterogeneous disease caused by glial or precursor cell mutation.It accounts for about 50%of tumors in children and 80%of malignant tumors.[1]The nucleotide excisio...To the Editor:Glioma is a highly invasive and lethal heterogeneous disease caused by glial or precursor cell mutation.It accounts for about 50%of tumors in children and 80%of malignant tumors.[1]The nucleotide excision repair(NER)pathway is a process that involves the sequential assembly of many proteins,including excision repair cross complementation group 1(ERCC1)and xeroderma pigmentosum complementation group F(XPF,also known as ERCC4).展开更多
Background:Glioma is one of the central nervous system(CNS)tumors in children,accounting for 80%of malignant brain tumors.Nucleotide excision repair(NER)is a vital pathway during DNA damage repair progression.Xeroderm...Background:Glioma is one of the central nervous system(CNS)tumors in children,accounting for 80%of malignant brain tumors.Nucleotide excision repair(NER)is a vital pathway during DNA damage repair progression.Xeroderma pigmentosum group D(XPD)or excision repair cross‐complementing group 2(ERCC2)is a critical factor in the NER pathway,playing an indispensable role in the DNA repair process.Therefore,the genetic variants in XPD may be associated with carcinogenesis induced by defects in DNA repair.Methods:We are the first to conduct a multi‐center case‐control study to investigate the correlation between XPD gene polymorphisms and pediatric glioma risk.We chose three single nucleotide polymorphisms and genotyped them using the TaqMan assay.Results:Although there is no significant association of these genetic variations with glioma susceptibility,the stratified analysis revealed that in the subtype of astrocytic tumors,the rs13181 TG/GG genotype enhanced glioma risk than the TT genotype,and carriers with two to three genotypes also elevated the tumor risk than 0‐1 genotypes.Conclusion:In conclusion,our findings provided an insight into the impact of XPD genetic variants on glioma risk.展开更多
文摘燃料电池作为一种清洁、高效的能量转换装置,其大规模应用受到阴极氧还原反应(ORR)动力学缓慢以及铂资源稀缺和价格高昂等的极大制约.尽管研究人员在过去几十年中付出了巨大努力,但研制高效、耐用的低Pt合金催化剂仍亟待突破.近年的研究表明,Pt的一些高指数晶面能够表现出比Pt(111)晶面更高的ORR活性,尤其是Pt(332),Pt(331)和Pt(554)等.同时,合金化能够通过电子与几何效应减弱含氧物种在Pt表面的吸附能,提升Pt合金催化剂的ORR活性.因此,高指数晶面和合金化的结合将是设计开发高性能电催化剂的有效手段.本文提出一种气氛调控的液相合成方法,通过在油胺中加热还原Pt化合物和Cu化合物,不添加其它保护剂,仅通过反应气氛的调控,成功制备了不同形貌的Pt-Cu合金纳米结构(纳米多脚、纳米凹立方体、纳米枝晶).通过反应前期引入氧化性气氛随后切换为惰性气氛的调控策略,合成具有高指数晶面的具有纳米枝晶结构的PtCu3合金;进一步对其进行电化学去合金化形成富Pt壳层,既保持其纳米枝晶形貌和高指数晶面,又形成具有梯度组成的PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶.相比而言,全程惰性气氛下生长得到纳米多脚结构,全程氧化性气氛下生长则得到纳米凹立方体.电化学测试结果表明,在0.1 M HClO4电解液中,PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶展现出较高的ORR活性,在0.9 V(vs.RHE)处的Pt质量活性和面积活性高达1.55 A mgPt^(-1)和2.4 mA cmPt^(-2),分别为商业Pt/C催化剂的14倍和24倍;此外,PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶具有良好的电化学稳定性能,经0.7~1.1 V(vs.RHE)电势范围内循环5000圈,其催化活性保持稳定.DFT计算表明,Cu合金效应和高指数晶面结构共同增强了Pt的ORR活性,其中PtCu_(3)@Pt_(3)Cu@Pt纳米枝晶高指数晶面台阶位点的氧结合能接近最优值,从而表现出火山顶点附近的ORR活性.
基金supported by grants from the National Natural Science Foundation of China(No.81802346)the China Postdoctoral Science Foundation(Nos.2020T130132,2020M682668)
文摘To the Editor:Glioma is a highly invasive and lethal heterogeneous disease caused by glial or precursor cell mutation.It accounts for about 50%of tumors in children and 80%of malignant tumors.[1]The nucleotide excision repair(NER)pathway is a process that involves the sequential assembly of many proteins,including excision repair cross complementation group 1(ERCC1)and xeroderma pigmentosum complementation group F(XPF,also known as ERCC4).
基金National Natural Science Foundation of China,Grant/Award Number:81802346。
文摘Background:Glioma is one of the central nervous system(CNS)tumors in children,accounting for 80%of malignant brain tumors.Nucleotide excision repair(NER)is a vital pathway during DNA damage repair progression.Xeroderma pigmentosum group D(XPD)or excision repair cross‐complementing group 2(ERCC2)is a critical factor in the NER pathway,playing an indispensable role in the DNA repair process.Therefore,the genetic variants in XPD may be associated with carcinogenesis induced by defects in DNA repair.Methods:We are the first to conduct a multi‐center case‐control study to investigate the correlation between XPD gene polymorphisms and pediatric glioma risk.We chose three single nucleotide polymorphisms and genotyped them using the TaqMan assay.Results:Although there is no significant association of these genetic variations with glioma susceptibility,the stratified analysis revealed that in the subtype of astrocytic tumors,the rs13181 TG/GG genotype enhanced glioma risk than the TT genotype,and carriers with two to three genotypes also elevated the tumor risk than 0‐1 genotypes.Conclusion:In conclusion,our findings provided an insight into the impact of XPD genetic variants on glioma risk.
