Heterogeneous Photocatalysis using Electroless Deposition of Ni/NiO Nanoparticles on Silicon Nanowires for the Degradation of Methyl Orange

Aims This work uses the MACE method to synthesize Si-NWs- Ni-NPs/NiONPs to degrade organic pollutants by photocatalysis. Background Photocatalytic degradation has been applied as an attractive solution to remove several organic pollutants. Heterostructured nanomaterials have become an interesting platform for investigation. Metal-assisted chemical etching (MACE) stands out as a promising technique because it is simple, low cost, and fast. Objective Attain the degradation of methyl orange (MO) in the presence of silicon nanowires (Si-NWs) in heterojunction with Nickel/Nickel Oxide nanoparticles (Ni-NPs-NiONPs). Methods Si-NWs were synthesized by metal (Ag) assisted chemical etching (MACE) of monocrystalline silicon wafers. Ni-NPs were non-electrolytically deposited on the Si-NWs (electroless method). The morphology of the Si-NWs- Ni-NPs/NiONPs was observed by SEM. Results Heterogeneous photocatalytic degradation of methyl orange (C14H14N3NaO3S) in an aqueous solution at a concentration of 20 ppm had an efficiency of 66.5% after 180 min under UV irradiation. The MO degradation percentage was determined using UV-visible spectrophotometry. Conclusion The Si-NWs-Ni-NPs/NiONPs were obtained composed mainly of Si covered by SiO2 decorated on the tips with Ni (II) in the form of NiO and a small amount of nickel metal. The removal efficiency obtained at 180 min of light exposure was 66.5%. After the photocatalysis tests, further oxidation of the Ni-NPS into NiONPS, was attributed to the reactive oxygen species in the aqueous medium based on the changes of the oxygen and Ni2p3/2 peaks by XPS. Other Through XPS, the oxidation state of the Si-NWs- Ni-NPs/NiONPs was analyzed.