Palladium Nanocatalysts on Hydroxyapatite: Green Oxidation of Alcohols and Reduction of Nitroarenes in Water

Shokouhimehr Shokouhimehr,Nasrollahzadeh Nasrollahzadeh,Yek Yek

doi:10.3390/app9194183

Shokouhimehr Shokouhimehr, Nasrollahzadeh Nasrollahzadeh + Show 1 more

Open Access

https://doi.org/10.3390/app9194183

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Abstract

A green procedure is described for supporting Pd nanoparticles on hydroxyapatite (HAP), which serves as a highly-stable heterogeneous catalyst displaying excellent activity for the aqueous expeditious reduction of nitroaromatics to the corresponding amines with sodium borohydride, and oxidation of primary and secondary alcohols by hydrogen peroxide with high yields and selectivities. The structural features of the prepared catalyst are confirmed by latest techniques including field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The reusability of the heterogeneous catalyst was affirmed in the aqueous reduction of nitrobenzene and oxidation of cycloheptanol for six consecutive runs without significant loss of catalytic activity.

Highlights

Nanoparticle-based catalysts are propounded as competent candidates for heterogeneous catalysis due to their enhanced catalytic activities and selectivities [1,2,3,4]; their surface area increases as the size decreases
The morphology, shape, and size of the prepared catalyst were identified by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) techniques
hydroxyapatite-supported Pd nanoparticles (HAP-Pd) (Figure 3) confirmed the successful preparation of the HAP-Pd, with the grain of the spherical Pd NPs pervading a good combination on the HAP surface

Summary

Introduction

Nanoparticle-based catalysts (nanocatalysts) are propounded as competent candidates for heterogeneous catalysis due to their enhanced catalytic activities and selectivities [1,2,3,4]; their surface area increases as the size decreases. HAP is a support with several appropriate properties with the formula Ca10 (PO4 ) (OH) ; specific features being its capability to form solid solutions and possessing a wide range of cationic and anionic substituents that can help stabilize the anchored nanocatalysts. It facilitates the separation process for the immobilized nanocatalysts, enhancing their reusability [21]; various noble metal nanocatalysts including Au, Pd, Pt, etc., have been immobilized on the surface of rigid. The obtained results showed that this supported Pd nanocatalyst is very effective as a heterogeneous catalyst

Experimental Section

Results and Discussion

TEM images

The intense

Heterogeneous

206 2064. Conclusions