Synthesis of Monodispersed Spherical Gold Nanoparticles Using 1,4‐Butynediol for Ultrafast Catalytic Reduction of Organic Dyes

ABSTRACT

In this work, monodispersed spherical gold nanoparticles are synthesized and demonstrated for catalytic reduction of organic dyes. Here, when the gold precursor and 1,4‐butynediol solutions are mixed, the color changes instantaneously from yellowish‐orange to wine‐red, indicating the formation of stable gold nanoparticles (AuNPs). The as‐synthesized AuNPs was confirmed by UV, XRD, TEM, and XPS analysis, which indicates the surface plasmon resonance peak at ∼520 nm, a face‐centered cubic crystal structure, monodispersed spherical nanoparticles (∼5.0 ± 1.0 nm), and oxidation states and elemental compositions, respectively. The catalytic reduction of organic dyes using methylene blue (MB) and rhodamine B (RhB) was demonstrated, and decoloration was observed within 70 s, indicating excellent catalytic activity. Moreover, time‐dependent UV‐visible spectra follows the pseudo‐first‐order kinetics with the rate constants of 0.075 s ⁻¹ for MB and 0.047 s ⁻¹ for Rh‐B. Besides, turnover frequency (TOF) was also calculated to assess the intrinsic catalytic activity, yielding values of 223 h ⁻¹ for MB and 146 h ⁻¹ for Rh‐B, along with excellent percentage catalytic efficiencies (∼99% MB and ∼96% RhB). The real‐world application was also demonstrated using a spiked water sample, and satisfactory performance was observed, indicating its potential for clean water applications and sustainability.