Abstract

Gold catalysts have been studied in-depth due to their unique activities for catalytic CO oxidation. Supports have intrinsic motivation for the high activity of gold catalysts. Thermally stable urchin-like CuO microspheres, which are potential support for gold catalysts, were prepared by facile solution-method. Then gold nanoparticles were loaded on them by deposition-precipitation method. The obtained gold catalysts were characterized by SEM, XRD, TEM, BET, ICP, and XPS. Their catalytic activity for CO oxidation was also evaluated. TEM results revealed that the gold nanoparticles with small sizes were highly distributed on the CuO surface in Au1.0/CuO-300. XPS observations demonstrated that the gold species in Au1.0/CuO-300 was of metallic state. Among the as-prepared catalysts, the Au1.0/CuO-300 catalyst displayed the best performance for CO oxidation and achieved 100% CO oxidation at 80 °C. It kept 100% conversion for 20 h at a reaction temperature of 180 °C, and showed good reusability after three reaction-cycles. The possible catalytic mechanism of Au1.0/CuO-300 catalyst for CO oxidation was also briefly proposed.

Highlights

  • Carbon monoxide (CO) is one of the major environment pollutants, and is one serious threat to human health [1]

  • In the late 1980s, it is confirmed that Au/metal-oxide catalyst possessed high catalytic performance in the low temperature for CO oxidation [4]

  • The chemical composition and oxidation state of elements on the surface of samples were identified by X-ray photoelectron spectroscopy (XPS) (Ulvac-Phi, Chigasaki, Japan) using an Al X-ray source (Al Ka150 W, PHI 5000 Versa Probe), and the binding energy was calibrated by taking C 1s peak at 284.6 eV as reference

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Summary

Introduction

Carbon monoxide (CO) is one of the major environment pollutants, and is one serious threat to human health [1]. The nanoscale noble-metals on metal-oxide semiconductor can efficiently obtain enhanced catalytic activity, which might be assigned to synergetic effect between support and gold particles. This effect could stimulate the charge delivery and energy transfer [3]. In the late 1980s, it is confirmed that Au/metal-oxide catalyst possessed high catalytic performance in the low temperature for CO oxidation [4]. Hutchings and co-workers prepared Au/CuO catalysts by coprecipitation (CP) method, which has highly sustained activity during CO oxidation process [19] Up to now, it has been well-proven that the size and morphology of CuO support could greatly affect the performance of catalyst. The catalytic mechanism of Au1.0/CuO-300 catalyst for CO oxidation were reasonably proposed

CuO Support Preparation
Catalyst Preparation
Characterization
Catalytic Activity
Results
Formation Mechanism of Urchin-Like CuO
Effect of Calcination Temperatures
Reusability and Stability Test
Mechanism
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