CO Oxidation at Near-Ambient Temperatures over TiO2-Supported Pd-Cu Catalysts: Promoting Effect of Pd-Cu Nanointerface and TiO2 Morphology.

Abdallah F Zedan,Kyriaki Polychronopoulou,Amina S Aljaber,Safa Gaber

doi:10.3390/nano11071675

Abstract

Significant improvement of the catalytic activity of palladium-based catalysts toward carbon monoxide (CO) oxidation reaction has been achieved through alloying and using different support materials. This work demonstrates the promoting effects of the nanointerface and the morphological features of the support on the CO oxidation reaction using a Pd-Cu/TiO2 catalyst. Pd-Cu catalysts supported on TiO2 were synthesized with wet chemical approaches and their catalytic activities for CO oxidation reaction were evaluated. The physicochemical properties of the prepared catalysts were studied using standard characterization tools including SEM, EDX, XRD, XPS, and Raman. The effects of the nanointerface between Pd and Cu and the morphology of the TiO2 support were investigated using three different-shaped TiO2 nanoparticles, namely spheres, nanotubes, and nanowires. The Pd catalysts that are modified through nanointerfacing with Cu and supported on TiO2 nanowires demonstrated the highest CO oxidation rates, reaching 100% CO conversion at temperature regime down to near-ambient temperatures of ~45 °C, compared to 70 °C and 150 °C in the case of pure Pd and pure Cu counterpart catalysts on the same support, respectively. The optimized Pd-Cu/TiO2 nanowires nanostructured system could serve as efficient and durable catalyst for CO oxidation at near-ambient temperature.

Highlights

The catalytic oxidation of carbon monoxide (CO) to carbon dioxide (CO2 ) over supported metal catalysts has been considered one of the most efficient technologies to remove toxic CO pollutants from the environment [1,2,3,4]
Great research efforts have been devoted to the improvement of the catalytic activity and stability of the Pd-based catalysts toward the low-temperature CO oxidation [9]
This study focuses on the rational synthesis of TiO2 -supported Pd-Cu catalysts and modulating their associated CO conversion temperatures by tailoring the Pd-Cu interface and the TiO2 morphology for enhanced activity in CO oxidation

Summary

Introduction

The catalytic oxidation of carbon monoxide (CO) to carbon dioxide (CO2 ) over supported metal catalysts has been considered one of the most efficient technologies to remove toxic CO pollutants from the environment [1,2,3,4]. Great research efforts have been devoted to the improvement of the catalytic activity and stability of the Pd-based catalysts toward the low-temperature CO oxidation [9]. To achieve this goal, several strategies have been investigated including alloying [10,11] or coupling different plasmonic materials, development of bimetallic catalysts [12] using different support materials [9,12]. Increasing the porosity of the support [13,14] and improving the metal–support interaction [10,15] as well as nanointerfacing. At the same time, establishing nanointerface between Pd and other metals has been shown

Methods

Results

Conclusion