Enhanced Decomposition of H2O2 Using Metallic Silver Nanoparticles under UV/Visible Light for the Removal of p-Nitrophenol from Water

Three Ag nanoparticle (NP) colloids are produced from borohydride reduction of silver nitrate in water by varying the amount sodium citrate. These nanoparticles used as photocatalysts with H2O2 to degrade a p-nitrophenol (PNP) solution. X-ray diffraction patterns have shown production metallic nanoparticles, whatever concentration The transmission electron microscope images these NPs highlighted evolution spherical hexagonal/rod-like broader distribution when citrate increases. Aggregate size solution has also same tendency. Indeed, citrate, which is both capping and reducing agent, modifies resulting shape NPs. When its low, pH higher, it stabilizes formation uniform However, increases, decreases, less controlled, leading bigger rod-like This results three different samples: one more 20 nm NPs, intermediate 30 50 broad distribution. mixed enhanced degradation PNP under UV/visible irradiation. produce localized surface plasmon resonance illumination, photogenerates electrons holes able accelerate hydroxyl radicals contact H2O2. morphology sample presents best activity, doubling compared irradiated experiment alone. better result can be attributed small (30 nm) but presence defects this structure that allows longer lifetime photogenerated species. Recycling experiments on photocatalyst showed constant activity up 40 h illumination for very low literature.