《厦门大学学报（自然科学版）》

传统的丙烯氧化反应的生产工艺复杂并且会带来大量污染废弃物,相比之下丙烯与氧气直接进行氧化反应具有很大的优势.然而,关于如何提高这种丙烯氧化反应的催化效率的报道较少.该文以Ag纳米立方体为种子,通过外延生长成功构建了具有核壳结构的Ag@Cu2O纳米立方体,研究了其核壳结构对光助丙烯氧化反应的影响.催化测试结果表明,Cu2O壳层有效抑制了丙烯的过度氧化,提高了丙烯醛的选择性.此外,Ag@Cu2O核壳结构不仅有助于Cu2O壳层的光生电子-空穴的高效分离,而且还可以充分利用内核Ag的表面等离子体共振效应提高局部反应温度.因此,这种核壳型催化剂能够有效地利用光来提高丙烯氧化的反应速率.

The direct oxidation of propylene to propylene oxides,such as acraldehyde,using molecular oxygen has many advantages over traditional processes that usually produce a large number of side products and require complex purification equipments.However,how to improve the catalytic efficiency of catalysts in the propylene oxidation reaction is still a great challenge.In this study,we successfully fabricated Ag@Cu2O core-shell heterostructure catalysts via the epitaxial growth of Cu2O on Ag nanocubes and studied their catalytic performances in the propylene oxidation reaction.Catalytic test results showed that the Cu2O shell efficiently suppressed the reaction of excessive oxidation of propylene and improved the selectivity of acrolein. Moreover, we found that the Ag@Cu2O core-shell heterostructure not only contributed to the efficient separation of photogenerated electron-hole in the Cu2O shell, but also made full use of the surface plasmon resonance effect of Ag core to elevate the local reaction temperature.As a result,this core-shell catalyst can effectively ultilize light to improve the reaction rate of propylene oxidation.

引言
1 实验部分
2 结果与讨论
3 结论

图1 Ag纳米立方体的SEM和粒径分布图(a)、TEM图(b)和XRD谱图(c)<br/>Fig.1 SEM image and particle size distributions(a), TEM image(b), and XRD pattern(c)of Ag nanocubes

图1 Ag纳米立方体的SEM和粒径分布图(a)、TEM图(b)和XRD谱图(c)
Fig.1 SEM image and particle size distributions(a), TEM image(b), and XRD pattern(c)of Ag nanocubes

图2 Ag@Cu2O纳米立方体的SEM图(a)、TEM图(b)及对应的SAED图(c),Ag@Cu2O纳米立方体核壳界面处的HRTEM图及相对应的Ag内核(右上角插图)和Cu2O外壳(左下角插图)的快速傅里叶变换模式图像(d),Ag@Cu2O纳米立方体HAADF-STEM图及对应的元素分布图(e)和XRD图(f)
Fig.2 SEM image(a), TEM image(b)and corresponding SAED pattern(c), HRTEM image of Ag@Cu2O nanocubes(d)and corresponding fast Fourier transform pattern of Ag(top-right inset)and Cu2O(bottom-left inset), HAADF-STEM image and corresponding elemental mapping images(e), XRD pattern(f)of Ag@Cu2O nanocubes

图3 Ag和Ag@Cu2O纳米立方体的紫外-可见吸收光谱图<br/>Fig.3 UV-Visible absorption spectra of Ag and Ag@Cu2O nanocubes

图3 Ag和Ag@Cu2O纳米立方体的紫外-可见吸收光谱图
Fig.3 UV-Visible absorption spectra of Ag and Ag@Cu2O nanocubes

图4 无光照条件下不同催化剂催化生成产物的产率(a,c,e)和选择性(b,d,f)随温度的变化曲线<br/>Fig.4 Temperature-dependent yield(a,c,e)and selectivity(b,d,f)curves of all productions over different catalysts in dark environment

图4 无光照条件下不同催化剂催化生成产物的产率(a,c,e)和选择性(b,d,f)随温度的变化曲线
Fig.4 Temperature-dependent yield(a,c,e)and selectivity(b,d,f)curves of all productions over different catalysts in dark environment

图5 光照条件下不同催化剂催化生成丙烯醛的产率(a)和选择性(b)随温度的变化曲线<br/>Fig.5 Temperature dependent yield(a)and selectivity(b)curves of acrolein production over different catalysis in light environment

图5 光照条件下不同催化剂催化生成丙烯醛的产率(a)和选择性(b)随温度的变化曲线
Fig.5 Temperature dependent yield(a)and selectivity(b)curves of acrolein production over different catalysis in light environment

图6 不同温度明暗条件下Ag和Ag@Cu2O纳米立方体催化丙烯氧化反应的丙烯醛产率对比<br/>Fig.6 Acrolein yield comparison of propylene oxidation reaction over Ag and Ag@Cu2O nanocubes in light/dark environment at different temperatures

图6 不同温度明暗条件下Ag和Ag@Cu2O纳米立方体催化丙烯氧化反应的丙烯醛产率对比
Fig.6 Acrolein yield comparison of propylene oxidation reaction over Ag and Ag@Cu2O nanocubes in light/dark environment at different temperatures

图7 Ag@Cu2O催化剂在不同温度下催化丙烯氧化反应后的TEM图<br/>Fig.7 TEM images of Ag@Cu2O nanocubes after catalytic propylene oxidation reaction at different temperatures

图7 Ag@Cu2O催化剂在不同温度下催化丙烯氧化反应后的TEM图
Fig.7 TEM images of Ag@Cu2O nanocubes after catalytic propylene oxidation reaction at different temperatures

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备注

引言

1 实验部分

2 结果与讨论

3 结论

学报简介

备注

引言

1 实验部分

2 结果与讨论

3 结 论

学报简介

3 结论