二维材料具有极限的尺寸和丰富的性质,是最有希望延伸摩尔定律的候选材料之一,因此是学术界和工业界关注的焦点. 2019年12期, SCIENCE CHINA Information Sciences组织出版了第一期"新型二维材料与器件应用专题",得到了广大...二维材料具有极限的尺寸和丰富的性质,是最有希望延伸摩尔定律的候选材料之一,因此是学术界和工业界关注的焦点. 2019年12期, SCIENCE CHINA Information Sciences组织出版了第一期"新型二维材料与器件应用专题",得到了广大读者的高度肯定和广泛引用.在过去一年中,国际和国内学者报道了众多二维材料领域的重要进展,包括高质量二维半导体和绝缘体单晶薄膜的制备、在2 nm技术节点以下的潜在优势,以及二维感算一体器件等.展开更多
The high cost of platinum(Pt)-group metal(PGM)-based catalysts used in proton-exchange membrane fuel cells(PEMFCs)poses a critical roadblock to their widespread adoption.Although using low PGM loading PEMFCs can large...The high cost of platinum(Pt)-group metal(PGM)-based catalysts used in proton-exchange membrane fuel cells(PEMFCs)poses a critical roadblock to their widespread adoption.Although using low PGM loading PEMFCs can largely address this challenge,high current density performance will be severely compromised consequently.To overcome this dilemma,we report the development of ultrathin platinum-cobalt nanowires(PtCoNWs)as the cathode catalysts for ultralow Pt loading and high-performance membrane electrode assembly(MEA).The Pt Co NWs delivered a record-high mass activity(MA)of 1.06±0.14 A mg_(Pt)^(-1) of Pt-alloy catalysts towards oxygen reduction reaction(ORR)in MEA,yielding an impressive total Pt utilization of 5.14 W_(rate)mg_(Pt)^(-1).The PtCoNWs retained a respectable endof-life MA of 0.45 Amg_(Pt)^(-1) after the 30,000 cycles square-wave accelerated stability test,which is still above the Department of Energy 2020 beginning-of-life target for catalysts.In-situ Xray absorption spectroscopy studies suggest that the high degree of alloying in the Pt Co NWs stabilizes the ultrathin structure and may contribute to the high ORR activity and power density performance in PEMFC.展开更多
Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec- tronic thin films. However, such solution-processed thin films are often plagued by excessive inter-particle resist...Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec- tronic thin films. However, such solution-processed thin films are often plagued by excessive inter-particle resistance and only exhibit limited current delivering capability. Here, we report a novel approach to fabricate highly conductive free-standing metallic thin film, accomplished by combining interfacial self-assembly of nanoparticles （NPs） and a light welding process. We found that light from a xenon lamp can weld adjacent Ag and Au NPs assembled at the water-air interface, forming a highly interconnected, free-standing metallic thin film structure with excellent electrical transport properties. With such a unique structure, the resultant thin metallic films show not only high flexibility and robustness, but also high conductivity comparable to bulk metallic thin films. Our studies offer a low-cost, room-temperature, and solution-processable approach to highly conductive metallic films. It can significantly impact solution-processable elec- tronic and optoelectronic devices.展开更多
文摘二维材料具有极限的尺寸和丰富的性质,是最有希望延伸摩尔定律的候选材料之一,因此是学术界和工业界关注的焦点. 2019年12期, SCIENCE CHINA Information Sciences组织出版了第一期"新型二维材料与器件应用专题",得到了广大读者的高度肯定和广泛引用.在过去一年中,国际和国内学者报道了众多二维材料领域的重要进展,包括高质量二维半导体和绝缘体单晶薄膜的制备、在2 nm技术节点以下的潜在优势,以及二维感算一体器件等.
基金support from the Office of Naval Research(N000141812155)support from the National Science Foundation(DMREF 1437263)supported in part by the National Science Foundation through the UC Irvine Materials Research Science and Engineering Center(DMR-2011967)。
文摘The high cost of platinum(Pt)-group metal(PGM)-based catalysts used in proton-exchange membrane fuel cells(PEMFCs)poses a critical roadblock to their widespread adoption.Although using low PGM loading PEMFCs can largely address this challenge,high current density performance will be severely compromised consequently.To overcome this dilemma,we report the development of ultrathin platinum-cobalt nanowires(PtCoNWs)as the cathode catalysts for ultralow Pt loading and high-performance membrane electrode assembly(MEA).The Pt Co NWs delivered a record-high mass activity(MA)of 1.06±0.14 A mg_(Pt)^(-1) of Pt-alloy catalysts towards oxygen reduction reaction(ORR)in MEA,yielding an impressive total Pt utilization of 5.14 W_(rate)mg_(Pt)^(-1).The PtCoNWs retained a respectable endof-life MA of 0.45 Amg_(Pt)^(-1) after the 30,000 cycles square-wave accelerated stability test,which is still above the Department of Energy 2020 beginning-of-life target for catalysts.In-situ Xray absorption spectroscopy studies suggest that the high degree of alloying in the Pt Co NWs stabilizes the ultrathin structure and may contribute to the high ORR activity and power density performance in PEMFC.
基金supported by the National Natural Science Foundation of China(21673070 and 61528403)the Opened Fund of the Chinese State Key Laboratory on Integrated Optoelectronics (IOSKL2015KF29)Hunan University
文摘Bottom-up assembly of nanostructured thin films could offer an alternative low-cost approach to elec- tronic thin films. However, such solution-processed thin films are often plagued by excessive inter-particle resistance and only exhibit limited current delivering capability. Here, we report a novel approach to fabricate highly conductive free-standing metallic thin film, accomplished by combining interfacial self-assembly of nanoparticles （NPs） and a light welding process. We found that light from a xenon lamp can weld adjacent Ag and Au NPs assembled at the water-air interface, forming a highly interconnected, free-standing metallic thin film structure with excellent electrical transport properties. With such a unique structure, the resultant thin metallic films show not only high flexibility and robustness, but also high conductivity comparable to bulk metallic thin films. Our studies offer a low-cost, room-temperature, and solution-processable approach to highly conductive metallic films. It can significantly impact solution-processable elec- tronic and optoelectronic devices.
