Homogeneous palladium nanoparticles surface hosts catalyzed reduction of the chromophoric azo (-N=N-) group of dye, acid orange 7 by borohydride in alkaline media

Article abstract of DOI:10.1002/kin.20883

In alkaline media, well-characterized gelatin-stabilized palladium (GPd) nanoparticles catalyze the reduction of the azo group containing pollutant dye, Acid Orange 7 (AO7) by sodium borohydride (NaBH4) to 1-amino-2-napthol and sulfanilic acid. Kinetic observations and detailed FTIR studies suggests that the reaction follows Langmuir-Hinshelwood kinetic model, where during the reaction both AO7 and borohydride are adsorbed on the GPd surface. Plots of lnk_o versus ln[AO7] or ln[NaBH₄] show that the order of reaction with respect to AO7 and NaBH₄ remains almost same over different molar ratios of [NaBH₄]/[AO7]. The catalyzed reaction shows an initial induction period (t0) due to a surface-restructuring process of GPd nanoparticles, and (1/t₀) can be defined as the rate of surface restructuring. The activation energy of the catalyzed reaction and energy of the surface-restructuring process of GPd are estimated as 22 ± 3 and 25 ± 7 kJ M^-1, respectively.