Developing green photochemical approaches towards the synthesis of carbon nanofiber- and graphene-supported silver nanoparticles and their use in the catalytic reduction of 4-nitrophenol

Abstract

A green, photochemical approach for the liquid-phase synthesis of carbon nanomaterialsupported silver nanoparticles is proposed. The method is based on irradiating a colloidal dispersion containing the carbon nanomaterial, a metal precursor and an environmentally friendly reducing agent (bioreductant) with UV light at room temperature. Two representative carbon materials have been used, namely, platelet-type graphite nanofibers and graphene oxide. The experimental conditions and possible mechanisms that afford the photochemical growth of the nanoparticles on each carbon support are also investigated and discussed. In addition, the resulting carbon-silver nanoparticle hybrids are demonstrated to be notably effective catalysts for the reduction of 4-nitrophenol to 4-aminophenol with NaBH 4 . Particularly, the graphene oxide-based samples were seen to exhibit exceptional catalytic activity towards such reaction. Finally, it is also shown that with a proper choice of bioreductant the present UV approach can afford highly reduced graphene oxide samples comparable to those attained with well-known, efficient chemical reductants (e. g., hydrazine at ~100 ºC), thus constituting an attractive room temperature alternative to such reduction methods.

Graphene supported heterogeneous catalysts: An overview

“…Several methods have been employed for the preparation of carbon supported catalyst including, impregnation [88,89], chemical vapor deposition [90,91], precipitation or coprecipitation method [92,93] and the liquid phase reduction [94,95]. Conventional producers for the preparation of carbon supported catalyst by either impregnation or precipitation methods normally yield a metal catalyst cluster with a heterogeneous particle size distribution [88,92].…”

Graphene Oxide–Silver Nanoparticle Nanohybrids: Synthesis, Characterization, and Antimicrobial Properties

“…GO plays an active role in the enhancement of the stability of the AgNPs, acting as a platform to prevent their agglomeration. The formation mechanism of the GO-AgNP hybrids seems to be through electrostatic interactions between the negatively charged oxygen-containing functional groups on the GO surface and the free silver ions, which are then reduced by the reducing agent, leading to the formation of AgNPs attached to the GO surface [11,18,21,22,67,73,74].…”

“Light-assisted evaporation induced self-assembly”: an efficient approach toward ordered carbon materials

“…Due to complexity and time consuming of the synthesis along to drawbacks related to harsh conditions required for template elimination, the so-template approach demonstrated to be a much simple and convenient alternative. Although few recent papers reported the synthesis of metal particles in the presence of carbon, 13 or modication of carbon surface chemistry 14 by light, to our knowledge, the preparation of ordered carbons by mean of light irradiation was not reported yet. 8 Particularly, the evaporation-induced selfassembly (EISA) is a suitable process to prepare ordered materials by means of wide synthetic conditions.…”