气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的...气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的高温动态烧结过程。实验发现,负载在CeO_(2)上的Au纳米颗粒在O_(2)与CO气氛环境中表现出不同的烧结行为,其在O_(2)气氛下具有较高的烧结速度,同时存在颗粒迁移与聚集长大(particle migration and coalescence,PMC)和奥斯特瓦尔德熟化(Ostwald ripening,OR)两种烧结过程;在CO气氛下烧结速度较慢,烧结过程以OR为主。对比不同气氛环境下烧结后催化剂的表面结构可知,CO增加了CeO_(2)表面台阶的数量以及表面氧空位浓度,增强了载体对Au颗粒的锚定作用,从而提升Au/CeO_(2)催化剂的稳定性。展开更多
为制备具有光热和光催化性能的双功能织物用于净化水,通过分子组装制备出兼具可见光与近红外响应的金氧化亚铜异质结纳米颗粒(Au@Cu_(2)O),使用轧-烘-焙将纳米材料整理到棉织物上,得到可用于界面蒸发生产清洁水的光热-光催化双功能棉织...为制备具有光热和光催化性能的双功能织物用于净化水,通过分子组装制备出兼具可见光与近红外响应的金氧化亚铜异质结纳米颗粒(Au@Cu_(2)O),使用轧-烘-焙将纳米材料整理到棉织物上,得到可用于界面蒸发生产清洁水的光热-光催化双功能棉织物。利用SEM、TEM、UV-VIS-NIR、XRD、FTIR等对Au@Cu_(2)O及Au@Cu_(2)O改性棉织物进行形貌、结构的表征,并对改性棉织物在模拟太阳光下对水的净化处理性能进行研究。结果表明:Au@Cu_(2)O改性棉织物具有良好的光热、光催化性能,在功率密度0.1 W cm^(2)的模拟太阳光源照射下,Au@Cu_(2)O改性棉织物的蒸发速率为1.25 kg(m^(2)·h),太阳光-蒸汽转换效率为77.4%,可见光辐照180 min后对甲基橙的降解率达到89.2%。制备的Au@Cu_(2)O改性棉织物在净化水领域展示出良好的应用潜力。展开更多
ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging issue.Herein,b...ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging issue.Herein,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this challenge.For the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) evolution.Furthermore,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer effect.Consequently,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,respectively.This work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.展开更多
文摘气氛环境下原位研究催化剂的烧结行为,能够为理解催化剂在预处理以及反应条件下的烧结机理和高稳定催化剂的设计提供重要的实验依据。本文以Au/CeO_(2)模型纳米催化剂为研究对象,利用环境透射电子显微镜原位观察其在O_(2)与CO气氛下的高温动态烧结过程。实验发现,负载在CeO_(2)上的Au纳米颗粒在O_(2)与CO气氛环境中表现出不同的烧结行为,其在O_(2)气氛下具有较高的烧结速度,同时存在颗粒迁移与聚集长大(particle migration and coalescence,PMC)和奥斯特瓦尔德熟化(Ostwald ripening,OR)两种烧结过程;在CO气氛下烧结速度较慢,烧结过程以OR为主。对比不同气氛环境下烧结后催化剂的表面结构可知,CO增加了CeO_(2)表面台阶的数量以及表面氧空位浓度,增强了载体对Au颗粒的锚定作用,从而提升Au/CeO_(2)催化剂的稳定性。
文摘为制备具有光热和光催化性能的双功能织物用于净化水,通过分子组装制备出兼具可见光与近红外响应的金氧化亚铜异质结纳米颗粒(Au@Cu_(2)O),使用轧-烘-焙将纳米材料整理到棉织物上,得到可用于界面蒸发生产清洁水的光热-光催化双功能棉织物。利用SEM、TEM、UV-VIS-NIR、XRD、FTIR等对Au@Cu_(2)O及Au@Cu_(2)O改性棉织物进行形貌、结构的表征,并对改性棉织物在模拟太阳光下对水的净化处理性能进行研究。结果表明:Au@Cu_(2)O改性棉织物具有良好的光热、光催化性能,在功率密度0.1 W cm^(2)的模拟太阳光源照射下,Au@Cu_(2)O改性棉织物的蒸发速率为1.25 kg(m^(2)·h),太阳光-蒸汽转换效率为77.4%,可见光辐照180 min后对甲基橙的降解率达到89.2%。制备的Au@Cu_(2)O改性棉织物在净化水领域展示出良好的应用潜力。
基金supported by the National Natural Science Foundation of China(Grant No.51871078 and 52071119)Interdisciplinary Research Foundation of HIT(Grant No.IR2021208)+1 种基金State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS38)Heilongjiang Science Foundation(No.LH2020B006).
文摘ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging issue.Herein,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this challenge.For the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) evolution.Furthermore,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer effect.Consequently,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,respectively.This work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.
