CuAg and AuAg bimetallic nanoparticles for catalytic and heat transfer applications

Anusha Dsouza,Koduri Ramam,S. C. Gurumurthy,Shridhar Mundinamani,M. S. Murari,Murali Gedda,B. S. Nagaraja,M. P. Shilpa

doi:10.1007/s10098-021-02120-0

Abstract

Bimetallic nanoparticles (BNPs) have drawn significant attention due to their numerous applications. They demonstrate enhanced optical, electrical, thermal, and catalytic properties due to the synergistic effects of monometals present in them. In this work, CuAg and AuAg BNPs have been synthesized using a facile and economical chemical reduction method. Optical characterization was carried out using UV–visible spectroscopy, and effect of pH on optical absorbance was studied. For CuAg and AuAg BNPs, optimum pH was observed to be at 9.4 and 6.39, respectively. Morphological investigation confirms the average diameters of CuAg and AuAg BNPs were to be 65 nm and 30 nm, respectively. Photocatalytic property illustrates the reduction of 4-nitrophenol to 4-aminophenol with a 92% conversion percentage in the presence of CuAg BNPs in 4 min, and rate constant for the reaction was measured to be 8.98 × 10–3 s−1. But for the AuAg BNPs, the conversion percentage was 97% in 8 min and rate constant was found to be 7.95 × 10–3 s−1. Thermal conductivity and viscosity measurements of the nanofluids obtained with CuAg and AuAg BNPs have ascertained them to be efficient candidates for the heat transfer and catalytic applications.Graphic abstract

Highlights

Nanostructured materials have prevailed superior characteristics over their bulk counterparts in the contemporary times owing to their unique and exceptional properties
Thermal conductivity of base fluid can be enhanced by the inclusion of metal NPs, whereas its heat transfer ability is boosted by incorporating the Bimetallic nanoparticles (BNPs)
These results indicate that CuAg BNPs are potential candidates for the heat transfer applications

Summary

Introduction

Nanostructured materials have prevailed superior characteristics over their bulk counterparts in the contemporary times owing to their unique and exceptional properties. Thermal conductivity of base fluid can be enhanced by the inclusion of metal NPs, whereas its heat transfer ability is boosted by incorporating the BNPs. other fluid properties such as density, viscosity, and specific heat should be taken care of. L. Godson et al showed that thermal conductivity of water can be increased by 80% by adding 0.9 vol% silver nanofluid at an average temperature of 70 °C (Godson et al 2010). Min-Sheng Liu et al prepared copper NPs by the chemical reduction method, and it efficiently improved the thermal conductivity of water (Liu et al 2006). Meena Kumari et al carried out a green synthesis technique for the preparation of Au–Ag BNPs using fruit juice of pomegranate (Meena Kumari et al 2015) Both core–shelland alloy-like nanostructures were formed based on the different molar ratios of gold and silver ions. The reactions that occur during the synthesis of AuAg BNPs are as follows (Kumar et al 2007; Suriati and Mariatti 2014): 2AuCl−4 + 3 CH2COOH 2C(OH)COO− → 2Au0 + 8Cl− + 3 CH3 2C=O + 9CO2 + 3H+ and 4Ag+ + C6H5O7Na3 + 2H2O → 4Ag0 + C6H5O7H3 + 3Na+ + H+ + O2

Results and discussion

Findings

Conclusion