Ag Nanoparticles-Based Zinc Hydroxide-Layered Hybrids as Novel and Efficient Catalysts for Reduction of 4-Nitrophenol to 4-Aminophenol

Fernando Junior Quites,Teresa D Z Atvars,Ailton José Terezo,Camila K S Azevedo,Richard Landers,Everton P P Alves,Rita C G Vinhas,José Carlos Germino

doi:10.5935/0103-5053.20160152

Abstract

Silver nanoparticles and zinc hydroxide-layered hybrid materials (AgNPs/ZHL) have been successfully developed as efficient catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride. A facile and rapid visible-light assisted green route was used for the deposition of silver nanoparticles (AgNPs) on the external surface of ZHL material. The resulting AgNPs/ZHL hybrids contained AgNPs with spherical morphology and uniform size distribution. Moreover, the AgNPs/ZHL compounds exhibited excellent catalytic performance (the reduction reaction was finished within 4 min) and reusability (three cycles) toward the reduction of 4-NP to 4-AP in presence of sodium borohydride. The reduction reaction obeyed the pseudo-first-order kinetics. The rate constants increased with the increase of amount of the AgNPs deposited into the hybrid materials. These results suggest that the as-prepared catalysts (AgNPs/ZHL) have great potential for heterogeneous catalytic applications.

Highlights

Under visible-light,[15] the Ag+ ions were reduced to Ag0, where the metal silver nanoparticles were anchored on zinc hydroxide-layered in nitrate form (ZHL) material
The ZHL particles presented a layered structure with the sheets separated by a d-spacing of 0.98 nm, where the nitrate ions are occluded between the inorganic lamellae (Figure 1a).[11,12,13,14]
From the X-ray diffraction (XRD) patterns, the size of the crystalline domains of ZHL, AgNPs(1)/ZHL and AgNPs(2)/ZHL materials were calculated as 280, 385 and 446 nm, respectively. These results indicated that the size of crystalline domains of the ZHL layered is increased with increasing AgNPs content

Summary

Introduction

Nitrophenolic compounds and their derivatives are environmental pollutants which sources may be as different as industrial effluents or the reaction products and degradation of certain pesticides, dyes, etc.[1,2,3] reduction reaction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) is important because nitrophenols and their derivatives are obtained during the production of herbicides, pesticides, synthetic dyes, etc.[1,2] a great deal of efforts have been challenged on the reduction of 4-NP to 4-AP in the last years.[1,2,3] Among them, the borohydride reduction of 4-NP to 4-AP by metal nanoparticles such as Ag, Au, Pt and Cu is attractive because this reaction can be performed in aqueous solution under mild condition.[1,2,3,4,5,6,7,8,9,10]Metal nanoparticles (NPs) have a variety of interesting properties, which enable them to play significant roles in a broad range of optic-electronic, biochemical and catalytic applications.[1,3,4] In special, silver nanoparticles (AgNPs) have.

Results

Conclusion