Identification of the Au/ZnO interface as the specific active site for the selective oxidation of the secondary alcohol group in glycerol

Pan, Yongning; Wu, Guandong; He, Yufei; Feng, Junting; Li, Dianqing

doi:10.1016/j.jcat.2018.10.030

Cited by 71 publications

(47 citation statements)

References 76 publications

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“…Fourth, the improved H 2 O 2 sensitivity is also implemented by the establishment of a well-developed Au-ZnO interface during postannealing. In regard to electronic sensitization effect, for ZnO, as a typical n-type semiconductor, its work function of 4.65 eV is smaller than the work function of Au (5.1 eV) [75]. Consequently, the electrons tend to transfer from a high energy state (ZnO) to a low energy state (Au).…”

Section: H 2 O 2 Sensing Propertiesmentioning

confidence: 99%

Nanoscale Au-ZnO Heterostructure Developed by Atomic Layer Deposition Towards Amperometric H2O2 Detection

Wei

Verpoort

et al. 2020

Nanoscale Res Lett

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Nanoscale Au-ZnO heterostructures were fabricated on 4-in. SiO 2 /Si wafers by the atomic layer deposition (ALD) technique. Developed Au-ZnO heterostructures after post-deposition annealing at 250°C were tested for amperometric hydrogen peroxide (H 2 O 2) detection. The surface morphology and nanostructure of Au-ZnO heterostructures were examined by field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), etc. Additionally, the electrochemical behavior of Au-ZnO heterostructures towards H 2 O 2 sensing under various conditions is assessed by chronoamperometry and electrochemical impedance spectroscopy (EIS). The results showed that ALD-fabricated Au-ZnO heterostructures exhibited one of the highest sensitivities of 0.53 μA μM −1 cm −2 , the widest linear H 2 O 2 detection range of 1.0 μM-120 mM, a low limit of detection (LOD) of 0.78 μM, excellent selectivity under the normal operation conditions, and great long-term stability. Utilization of the ALD deposition method opens up a unique opportunity for the improvement of the various capabilities of the devices based on Au-ZnO heterostructures for amperometric detection of different chemicals.

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Section: H 2 O 2 Sensing Propertiesmentioning

confidence: 99%

Nanoscale Au-ZnO Heterostructure Developed by Atomic Layer Deposition Towards Amperometric H2O2 Detection

Wei

Verpoort

et al. 2020

Nanoscale Res Lett

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“…Developing profitable applications of glycerol (GLY), the main cheap by product in biodiesel production process, is of great importance for the sustainable extension of biodiesel industry chain. [1][2][3][4][5] Up to date, selective oxidation of GLY on heterogeneous catalysts without the addition of liquid alkali attracted much attention due to the production of various valuable fine chemicals such as glyceric acid (GLYA), glycollic acid (GLYOA) and dihydroxyacetone (DHA). 6 Moreover, it offers an efficiently, environmentally and economically alternative to traditional time-consuming, polluting base (or heavy metal oxidant)promoted and costly methods as well as biological oxidation processes.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Au‐Promoted Pt nanoparticles supported on MgO/SBA‐15 as an efficient catalyst for selective oxidation of glycerol

et al. 2021

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A systematic study of Au-promoted and unpromoted Pt/MgO/SBA-15 catalyst is developed to separate the promoter effect from electron transfer effect between Au and Pt. Multi-characterizations revealed that Au and Pt metals in these bimetallic catalysts mainly exist in the form of alloy, and the main role of Au is to reduce the size of AuPt alloy nanoparticles, thus enhancing the adsorption and activation of intermediate products. Through the optimization of various factors (including MgO content, Au/Pt molar ratio, reaction temperature and time), the Au 1 Pt 2 /MgO/SBA-15 (0.05) catalyst exhibits excellent catalytic activity and glyceric acid selectivity for the selective oxidation of glycerol. Density functional theory calculation confirmed that the synergistic effect between Pt and Au active sites could facilitate the oxidation of primary hydroxyl group by promoting the activation of C H bond and the oxidation of aldehyde group. The results may give insights on designing effective Pt based bimetallic catalyst for selective oxidation of glycerol.

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“…It is commonly accepted that metal alkoxide formation by adsorption of alcohol on the Au surface could be the initial step during alcohol oxidation over Au catalysts . Under the present reaction conditions, it is likely that the secondary OH group in GLY was adsorbed dissociatively onto the Au nanoparticles to generate metal alkoxide intermediates via activation of the OH bond . Bonding of the dissociated hydrogen to the lattice oxygen at the Au–support perimeter produced surface OH .…”

Section: Resultsmentioning

confidence: 90%

“…45 Under the present reaction conditions, it is likely that the secondary OH group in GLY was adsorbed dissociatively onto the Au nanoparticles to generate metal alkoxide intermediates via activation of the O-H bond. 46 Bonding of the dissociated hydrogen to the lattice oxygen at the Au-support perimeter produced surface O-H. 47 In the second step, ketones were produced by -H elimination at Au nanoparticles, which could occur via transfer of either a hydrogen atom or hydride. 48 This could be the rate-determining step, and the free step edges or other defect sites on Au particles are more active in C-H bond breakdown.…”

Section: Catalytic Performancementioning

confidence: 99%

Conversion of glycerol to dihydroxyacetone over Au catalysts on various supports

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND Glycerol, which is a coproduct of biodiesel production, has been identified as a key platform compound for producing various valuable chemicals. The selective catalytic oxidation of glycerol to dihydroxyacetone is very attractive. RESULTS A series of Au catalysts supported on metallic oxides, i.e. ZnO, CuO, Al2O3, Fe2O3 and NiO, were studied for selective catalytic oxidation of glycerol to dihydroxyacetone under base‐free conditions. Among the catalysts, Au/CuO showed the best catalytic activity (glycerol conversion of 89% and dihydroxyacetone selectivity of 82.6% at 80 °C under 10 bar of O2), followed by Au/ZnO ≫ Au/NiO > Au/Al2O3 ≈ Au/CuO‐SD ≈ Au/Fe2O3. The catalytic behaviors of these supported Au catalysts varied depending on the Au particle size, Au oxidation state, Au–support interactions and lattice oxygen reducibility. CONCLUSION The main reasons for the high catalytic activity of Au/CuO are as follows. Firstly, the catalyst has small metallic Au particles, which are more active in cleavage of the secondary CH bond in glycerol molecules. Secondly, the interactions between Au and CuO facilitate lattice oxygen reduction, and this increases oxygen mobility, which may promote regeneration of Au–support perimeter active sites by gaseous oxygen. © 2019 Society of Chemical Industry

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Identification of the Au/ZnO interface as the specific active site for the selective oxidation of the secondary alcohol group in glycerol

Cited by 71 publications

References 76 publications

Nanoscale Au-ZnO Heterostructure Developed by Atomic Layer Deposition Towards Amperometric H2O2 Detection

Nanoscale Au-ZnO Heterostructure Developed by Atomic Layer Deposition Towards Amperometric H2O2 Detection

Au‐Promoted Pt nanoparticles supported on MgO/SBA‐15 as an efficient catalyst for selective oxidation of glycerol

Conversion of glycerol to dihydroxyacetone over Au catalysts on various supports

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