Synthesis of bimetallic Pt–Cu nanoparticles and their application in the reduction of rhodamine B

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 416; no. 5; pp. 43 - 50
• Main Authors: Singh, Henam Premananda, Gupta, Nikesh, Sharma, Surinder Kumar, Sharma, Rakesh Kumar
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.01.2013
• Subjects: absorbance; Bimetallic nanoparticles; catalysts; catalytic activity; colloids; copper; hexane; hydrazine; NaBH4; nanoparticles; Reverse micelle; Rhodamine B; spectroscopy; synergism; Synergistic effect; temperature; transmission electron microscopy; X-ray diffraction; NaBH4; Rhodamine B; Synergistic effect; Bimetallic nanoparticles; Reverse micelle
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2012.09.048

Bimetallic Pt–Cu nanoparticles shows higher catalytic efficiency as Compared to their monometallic counterpart of same size. [Display omitted] ► Mono and bimetallic nanoparticles (Pt and Cu) of size 3nm were synthesized. ► Bimetallic nanoparticles are better catalyst for the reduction of rhodamine B. ► Synergistic effect of two metals increases the rate of catalytic reaction. Monometallic (Pt and Cu) and bimetallic (Pt–Cu) nanoparticles were synthesized in water-in-oil microemulsions of water/AOT/hexane by the reduction of their corresponding salt (H2PtCl6 and (CH3COO)2Cu·H2O) with hydrazine hydrate under low temperature condition (5°C). The particles were characterized for their size, morphology, composition, charge and optical behavior using various techniques like TEM, SAED, DLS, XRD, EDAX, UV–vis spectroscopy, etc. The prepared nanoparticles were reasonably monodispersed with spherical morphology having an average diameter of 3nm. The synthesized mono and bimetallic nanoparticles were utilized as catalyst in the reduction of a dye rhodamine B (Rh B) using NaBH4 which is otherwise extremely slow. The reaction was studied by observing the decrease in absorbance at 554nm (characteristic peak of the dye) spectrophotometrically and a comparative study for the catalytic performance of the synthesized bimetallic and individual monometallic nanoparticles was done for the reduction reaction. The degradation reaction follows first order kinetics and the rate constant k, calculated for bimetallic Pt–Cu, monometallic Cu and Pt nanoparticles and uncatalyzed reactions comes out to be 4.5×10−2s−1, 2.7×10−3s−1, 8.0×10−4s−1 and 5.0×10−5s−1 respectively, i.e. the rate constant follows the order kbimet>kCu>kPt>kuncat. Our results show that bimetallic Pt–Cu nanoparticles are very promising for catalytic application as compared to their monometallic nanoparticles which may be attributed to its small size and synergistic effect of two metal nanoparticles.