Phenol removal and hydrogen production from water: Silver nanoparticles decorated on polyaniline wrapped zinc oxide nanorods

Abstract

The toxic and carcinogenic organic compounds discharge from industries, contaminate the natural reservoirs of water and air which eventually pose a global threat not only to the aquatic life but also to the humanity. Herein, ternary nanocomposites of silver-nanoparticle (AgNPs)-decorated on polyaniline (Pani)-wrapped zinc oxide nanorods (AgNPs@Pani/ZnO) were prepared via a facile approach. The nanocomposite degraded 97.91% phenol with an optimized dosage and concentration of H2O2. Moreover, the apparent rate constant for phenol degradation was 3.69 times higher than for pure ZnO nanorods. The hydrogen production from AgNPs@Pani/ZnO was 1.58 and 2.74 times higher than Pani/ZnO and ZnO, respectively. The enhanced phenol degradation and hydrogen production is attributed to the transfer of holes to the Pani, from which the electrons were transferred to the conduction band of ZnO and eventually to the conduction band of the AgNPs, where they accelerated the redox reactions for rapid photolysis of water and phenol. The concentration of the catalyst dosage affected the rate of phenol degradation. Further, response surface methodology was also applied in order to design 13 sets of random experiments in which the catalyst dosage and degradation time were varied to predict the phenol degradation.