Ranolazine-functionalized CuO NPs: efficient homogeneous and heterogeneous catalysts for reduction of 4-nitrophenol

Abstract

In the present study copper oxide nanoparticles (CuO NPs) were synthesized using a hydrothermal methodwith ranolazine as a shape-directing agent. Ranolazine-functionalized CuO NPs were characterized by various analyticaltechniques such as scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and X-raydiffraction (XRD). The SEM pattern confirmed the morphology of ranolazine-functionalized CuO NPs with well-definedrice-like structures. FTIR spectroscopy confirmed the interaction between CuO NPs and ranolazine. The XRD analysisindicated that the structure of ranolazine-functionalized CuO NPs was monoclinic crystalline and the size ranged between9 and 18 nm with an average particle size of 12 nm. The smaller size range of CuO NPs gave a large surface area thatenhanced the efficiency of these catalysts employed for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP)in the H2 O system. In homogeneous catalysis, results showed that 50 µL of CuO NPs was required in the presenceof NaBH4 for 99% reduction of 4-NP in 240 s. On the other hand, for heterogeneous catalysis, 0.5 mg of CuO NPswas used in the presence of NaBH4 for 99% catalytic reduction of 4-NP to 4-AP in 320 s. The rate of reaction forhomogeneous catalysis and heterogeneous catalysis was determined from the plots of In(Ct /C0) of 4-NP versus time (s),which showed good linearity with values of 1.3 × 10 −2and 8.8 × 10 −3s−1. respectively. The high-quality catalyticefficiency, good reusability, nontoxic nature, and low cost are favorable properties of the synthesized CuO NPs for useas efficient catalysts for reduction of 4-AP to 4-NP in both homogeneous and heterogeneous media.