Research ArticleChemistry

Plasmonic nanoreactors regulating selective oxidation by energetic electrons and nanoconfined thermal fields

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Science Advances  05 Mar 2021:
Vol. 7, no. 10, eabf0962
DOI: 10.1126/sciadv.abf0962
  • Fig. 1 Characterization of Au-Cu2O catalyst and its catalytic performance response to illumination.

    (A) Schematic of the SP-regulated partial oxidation of propylene on the Au-Cu2O plasmonic structure. (B) SEM image of the as-prepared Au-Cu2O hierarchical structure. (C) XRD patterns of the as-prepared C-Cu2O and Au-Cu2O hierarchical structure. a.u., arbitrary unit. (D) XPS of Cu of the as-prepared C-Cu2O and Au-Cu2O hierarchical structure. (E) Conversion and selectivity of the partial propylene oxidation for Au-Cu2O at 150°C with and without illumination, showing the improvement in conversion induced by light and the influence on product selectivity. (F) Conversion of propylene for Cu2O and Au-Cu2O with and without illumination at various temperatures. (G) Conversion enhancements induced by illumination for Cu2O and Au-Cu2O as a function of the operating temperature. (H) Selectivity of acrolein catalyzed by Cu2O (gray) and Au-Cu2O (red) with and without illumination as a function of propylene conversion. (I) Selectivity of CO2 for Cu2O (gray) and Au-Cu2O (red) with and without illumination as a function of propylene conversion.

  • Fig. 2 The light intensity– and wavelength-dependent experiments and the catalytic performance of Au@SiO2-Cu2O catalyst.

    (A) Catalytic performance (conversion and selectivity) for the Au-Cu2O hierarchical structure at 150°C as a function of incident light intensity. (B) Catalytic performance (conversion and selectivity) for the Au-Cu2O hierarchical structure at 150°C as a function of incident light wavelength. The red curve is the extinction spectrum of Au NPs. (C) Conversion and conversion enhancement for the Au@SiO2-Cu2O hierarchical structure with and without illumination at various temperatures. (D) Formation rate enhancement of acrolein and PO as a function of temperature using Cu2O, Au-Cu2O hierarchical structure and Au@SiO2-Cu2O hierarchical structure as catalyst, calculated by dividing the formation rate of acrolein or PO with illumination by that without illumination.

  • Fig. 3 The calculated heating effect with various particle concentrations.

    (A) The temperature distribution at a low surface particle density of 25/μm2; the temperature field is localized in the vicinity of particle. (B) The temperature distribution with a moderate surface particle density of 300/μm2; the temperature field is localized in the vicinity of the particle, and the collective heating effect yields a temperature rise in surrounding medium. (C) The temperature distribution with a high surface particle density of 1300/μm2; the temperature is delocalized with a notable temperature increase of the surrounding medium. (D) Temperature distributions as a function of X, as shown in (A) (blue solid line), (B) (red solid line), and (C) (yellow solid line). A moderate particle density can produce a considerable localized temperature with great gradient around particles and certain temperature increase of the surrounding medium. Particle arrays (11 × 11) with various periodicities were used to simulate the particle-covered substrate surface. A section of the plane 2 nm above the substrate is used to facilitate a top view of the temperature distribution.

  • Fig. 4 Schematic of the photoelectronic and photothermal contributions to the chemical reaction.

    Both energetic electrons and local heating effects influence the chemical reaction but through different ways. The energetic electrons regulate the reaction path to improve the acrolein selectivity. The local heating effect of SPs in the hierarchical structure can isolate the active region to eliminate consecutive reactions, thus greatly reducing overoxidation and increasing the selectivity of all partial oxidation products.

Supplementary Materials

  • Supplementary Materials

    Plasmonic nanoreactors regulating selective oxidation by energetic electrons and nanoconfined thermal fields

    Chao Zhan, Qiu-Xiang Wang, Jun Yi, Liang Chen, De-Yin Wu, Ye Wang, Zhao-Xiong Xie, Martin Moskovits, Zhong-Qun Tian

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    • Sections S1 and S2
    • Figs. S1 to S48
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