Catalytic Reduction of p‐Nitrophenol and Hexacyanoferrate (III) by Borohydride Using Green Synthesized Gold Nanoparticles

Abstract

A simple and green approach for the synthesis of well‐stabilized gold nanoparticles (AuNPs) using gum Acacia (GA) is presented here. The gum acacia acts as the reductant and stabilizer. The synthesized gold nanoparticles were characterized by using ultraviolet visible (UV‐Vis), fourier transform infrared spectroscopy (FTIR), x‐ray diffraction (XRD), dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. The UV‐Vis study revealed a distinct surface plasmon resonance at 520 – 550 nm, due to the formation of AuNPs. FTIR analysis showed the evidence that –OH groups present in the gum matrix were responsible in reducing the tetra chloroauric acid into AuNPs. XRD studies confirmed the formation of well crystalline nanoparticles with fcc structure and the particle size ranges from 4 – 29 nm, as indicated by TEM analysis. The synthesized gold nanoparticles exhibited homogeneous catalytic activity. The two model reactions studied were the reduction of p‐nitro phenol and the reduction of hexacyanoferrate (III) by borohydride ions. Both the reactions were monitored by UV‐Vis spectroscopy. The kinetic investigations were carried out for the AuNPs‐catalyzed reactions at different temperatures and different amount of catalyst.

Microwave-irradiated green synthesis of gold nanoparticles for catalytic and anti-bacterial activity

“…It was noticed that the increase in temperature helps the rate of the reaction to increase. The catalytic studies were performed using the AuNPs, which exhibit higher catalytic performance compared to other earlier reported results (Reddy et al 2015a;Tao et al 2017). The activation energy was calculated from the slope (-Ea/R) of the straight line and was found to be 28.15 ± 1.14 kJ/mol.…”

“…Metal nanoparticles are unique building blocks with sophisticated electromagnetic, chemical and optical properties that differ dramatically from those of bulk metals (Murray 2008;Sardar et al 2009). Among several metal nanoparticles, gold nanoparticles have excellent applications in diagnostics, imaging, sensing, catalytic, electrical, magnetic, anti-bacterial activity, and drug delivery (Cuenca et al 2006;Ulvestad et al 2015;Ojo et al 2016;Deng et al 2014;Reddy et al 2015a;Dahl et al 2007;Prakash et al 2013;Madhusudhan et al 2014;Rodrı´guez-Sa´nchez et al 2000;Lateef et al 2016). …”

“…But gold in the form of nanoparticles shows excellent catalytic activity towards the deoxygenation of epoxides into alkenes and reduction of ferrocyanate (III) and nitroarenes (Reddy et al 2015a;Ju and Parales 2010). The 4-NP, along with other nitro phenols and derivatives, is a common by-product in the production of pesticides, synthetic dyes, drug industries and herbicides.…”

Microwave-assisted synthesis of silver nanoparticles and their application in catalytic, antibacterial and antioxidant activities

“…After the addition of AgNPs, the intensity decrease was monitored using UV-Vis spectrophotometer. The electron transfer reaction was performed at different temperatures between 30 and 70 °C [36,45].…”

“…6). The redox reaction is a pseudo first-order reaction with respect to hexacyanoferrate(III) [45]. As the centralization of NaBH 4 was more noteworthy than the hexacyanoferrate(III), the reduction rate can be thought to be autonomous of NaBH 4 quantity.…”