Chemical Synthesis of Bimetallic Ag/Co Nanoparticles for Colorimetric Detection of Cr3+ and Fe3+ and Its Catalytic Performance.

Precious metal nanoparticles, especially Ag-based nanoparticles due to their strong surface plasma effect and excellent catalytic performance, have been widely applied in environmental remediation and detection of heavy metal ions in aqueous solution. In this study, first, bimetallic Ag/Co nanoparticles (Ag/Co NPs) modified by sodium citrate were synthesized by chemical reduction method. Second, bimetallic Ag/Co NPs were used as colorimetric probe for detecting Cr 3 + and Fe 3 + in aqueous solution simultaneously for the first time. The results showed that the probe had high specificity towards Cr 3 + and Fe 3 + among the tested metal ions. When Cr 3 + was mixed with Ag/Co NPs, the solution quickly changed from yellow to pink, meanwhile, the UV–Vis absorption intensity declined at 400 nm and a new prominent absorption band was formed at 530 nm. While Fe 3 + was mixed with Ag/Co NPs, the solution quickly changed from yellow to nearly colorless. The linear relationship between absorbance of bimetallic Ag/Co NPs at 400 nm and −log of Cr 3 + concentration is 1 nM to 10 μ M, which y = 0. 0 0 8 4 x + 1. 5 0 1 2 and R 2 = 0. 9 8 5 5. The limit of detection (LOD) for this study was 1.14 nM. Similar to Cr 3 + , the LOD for Fe 3 + was calculated 16.3 μ M. In addition, the catalytic performance of bimetallic Ag/Co NPs was evaluated by methylene blue (MB) in the presence of H2O2. The catalytic degradation efficiency of bimetallic Ag/Co NPs was about 4.8 times greater than monometallic Ag NPs, confirming Ag and Co NPs had obviously synergistic effect. Therefore, this result made bimetallic Ag/Co NPs had potential application in the field of environmental remediation. Bimetallic Ag/Co nanoparticles (NPs) modified by sodium citrate were synthesized by chemical reduction method. The prepared Ag/Co NPs were used as a colorimetric probe for detecting Cr3+ and Fe3+ in aqueous solution simultaneously for the first time. Furthermore, the catalytic performance of bimetallic Ag/Co NPs was evaluated by methylene blue in the presence of H2O2. The catalytic degradation efficency of bimetallic Ag/Co NPs was 4.8 times greater than monometallic Ag NPs, confirming that Ag and Co NPs have a synergistic effect. [ABSTRACT FROM AUTHOR]