Carbon Dots Assisted Synthesis of Gold Nanoparticles and Their Catalytic Activity in 4‐Nitrophenol Reduction

Abstract

A novel biocompatible carbon nanoparticles, i. e., carbon dots (CDs) are prepared from cheap organic precursors and are used to synthesize gold nanoparticles (AuNPs). The formation of CDs are confirmed from their absorption and emission properties. The CDs not only acts as reducing agent but also stabilizes the resulting AuNPs. The high stabilizing effect of CDs can be attributed to their hydrophilic surfaces due to the presence of ‐C=O, ‐OH, etc. functional group as confirmed from FTIR spectral analysis. Basically, two types of AuNPs are observed, one is decahedron type particles and the other one is triangular plates. The size of decahedron type AuNPs are measured to be ∼ 30 nm, whereas those of triangular plates are ∼ 100 nm. These mixture of AuNPs are used to study a model catalytic reaction, i. e., reduction of 4‐nitrophenol by NaBH4 in which the reaction is completed in 5 Mins and the reaction follows the first order kinetics with a first order rate constant of 1.28 min−1. Moreover, the resulting AuNPs can be reused for further reactions and up to 4 cycles it has been observed that the efficiency of conversion remains ∼100% with this AuNPs catalyst. Thus, functional CDs not only catalyse the formation of AuNPs, but also give them enough stability for catalytic applications in many organic transformation reactions.

One-step chemical synthesis of Ag–Au alloy nanoparticles for modulating the catalytic hydrogenation reaction

“…Furthermore, the converted product, i.e., aromatic amino derivatives can be useful precursor materials for manufacturing various drug molecules and also in making photographic plates (Zhao and Astruc 2015). Moreover, our research group is also actively involved in studying and modulating the catalytic activity of metal nanoparticles through various approaches (Ghosh et al 2019;Mohanta et al 2016;Satapathy et al 2016Satapathy et al , 2017.…”

Parameters Affecting Methylene Blue Dye Photodegradation by Carbon dots Prepared from Olive Pomace

“…Another weak absorption peak can be observed at around 300 nm, which is ascribed to the n-π* electron transition of hydrophilic groups, mainly CÀ O, C = O, and COÀ H, due to the oxidation state. [32,35] Moreover, the indirect band gap of CNDs was estimated by Tauc's plot by performing the following equation (αhv) 1/2 = B(hv-E g ) , where α is the absorption coefficient, hv is the photon energy (hv = 1240/λ), λ = is the wavelength, B is constant, and E g is the band gap energy. Then by plotting (αhv) 1/2 versus hv as shown in Figure 3b (Inset).…”

Two-dimensional MXene enabled carbon quantum dots@Ag with enhanced catalytic activity towards the reduction of p-nitrophenol

“…19 Ghosh et al reported a novel approach for synthesis of Au NPs by using CQDs as reducing as well as stabilizing agent, which can enhance catalytic activity towards reduction of PNP. 20 Although nanocomposites have better catalytic properties than NPs, agglomeration occurs during the catalytic process due to their high surface energy, affecting catalytic activity and experimental reproducibility. 21 The newly-fashioned 2D layered inorganic materials, such as silicene, black phosphorus (BP), transition metal oxides (TMOs), graphitic carbon nitride (g-C 3 N 4 ), and MXenes etc., have attracted a lot of attention due to their unique properties and important applications.…”

“… 19 Ghosh et al reported a novel approach for synthesis of Au NPs by using CQDs as reducing as well as stabilizing agent, which can enhance catalytic activity towards reduction of PNP. 20 Although nanocomposites have better catalytic properties than NPs, agglomeration occurs during the catalytic process due to their high surface energy, affecting catalytic activity and experimental reproducibility. 21 …”