Ammonium bicarbonate reduction route to uniform gold nanoparticles and their applications in catalysis and surface-enhanced Raman scattering

Abstract

A new protocol for the synthesis of nearly monodisperse gold nanoparticles with controllable size is described. The pathway is based on the reduction of AuCl 4 -by ammonium bicarbonate in the presence of sodium stearate under hydrothermal conditions. The particle sizes could be easily tuned by regulating the reaction conditions including precursor concentration, reaction temperature and growth time. A tentative explanation for the reduction and growth mechanism of uniform gold nanoparticles has been proposed. The as-prepared gold particles showed good catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol by excess NaBH 4 , and a surface-enhanced Raman scattering (SERS) study suggested that the gold nanoparticles exhibited a high SERS effect on the probe molecule Rhodamine 6G.

Electrocatalytic performance of environmentally friendly synthesized gold nanoparticles towards the borohydride electro-oxidation reaction

“…The absorbance increased with increasing glycerol concentration. The colloidal AuNps spectra had a maximum absorbance at around 520 nm regardless of the glycerol concentration, a value which agrees very well with data in literature [1,30,31]. The red color is due to the surface plasmon band (SPB), a broad absorption band in the visible region.…”

Plant‐supported silver nanoparticles: Efficient, economically viable and easily recoverable catalyst for the reduction of organic pollutants

“…The calculated rate constants were 2.28 × 10 −3 , 2.01 × 10 −3 , 2.23 × 10 −3 and 2.06 × 10 −3 s −1 for 0.25, 0.50, 0.75 and 1 M sodium borohydride, respectively (Figure S3b). The NaBH 4 content in the reactive system significantly exceeds that of 4‐NP, as proved experimentally that the reduction rate of 4‐NP is supposed to be independent of the NaBH 4 concentration and thus the reaction kinetics of 4‐NP reduction to 4‐AP can be treated as pseudo‐first‐order kinetics in 4‐NP concentration . Thus, in the presence of even a large amount of NaBH 4 concentration as compared to 4‐NP, the reduction rate is independent of the NaBH 4 concentration.…”

Solvothermal synthesis of metal nanocrystals and their applications

“…Gold nanoparticles have advanced from being viewed as simple carriers in biomedical applications to mediating biological effects [27,108]. Gold nanocrystals with varying morphologies synthesized under solvothermal synthesis are summarized in Table 3 [109][110][111][112][113][114]. Monodisperse gold octahedra with sizes of 30, 60, 90, 120, and 150 nm were obtained by heating an aqueous solution of HAuCl 4 , trisodium citrate, and CTAB at 110 • C for 6, 12, 24, 48, and 72 h, respectively.…”