Fabrication of nanoporous silica using P-123 and F-127 surfactants and its application as a support for Au nanoparticle catalysts in the p-nitrophenol reduction

p-Nitrophenol is a hazardous water pollutant in the category of aromatic nitro compounds, and its presence in aquatic environments can be minimized by reducing it to the less toxic compound, p-aminophenol. This study explores an effective and low-cost method to achieve this transformation by using heterogeneous catalysts. Au nanoparticle hybrid materials supported by nanoporous silica were synthesized to enhance the catalytic activity and prevent the Au nanoparticle agglomerates. Nanoporous silica was synthesized using Pluronic (c) P-123 and Pluronic (c) F-127 templates in various ratios, i.e., 1:0, 1:2, 2:1, and 0:1. The observation by Transmission Electron Microscope revealed that the existence of nanoporous silica in Au nanoparticle's catalyst yielded irregular pore distribution. Furthermore, the pore sizes were decreased with increasing Pluronic (c) P-123. The result of the catalytic study of various mass ratios represents the Au- nanoporous silica with a 1:0 ratio of Pluronic (c) P-123: F127 has the highest catalytic activity, with an average pore diameter of 10.8 nm, a pore volume of 0.77 cm3 g- 1, and a surface area of 328 m2 g-1. The catalytic efficiency reached 95.06 % within 12 min, with an observed rate constant of 0.3685 min- 1. The mechanism in this reaction follows the Langmuir-Hinshelwood model, with pnitrophenol and NaBH4 adsorbing on the catalyst surface prior to the reaction.