Surface functionalization of MnO2 NW embellished with metal nanoparticles for self-cleaning applications

The present study investigates the synthesis of vertically aligned MnO 2 nanowires (NW) decorated with gold (Au) and silver (Ag) nanoparticles (NP) via the glancing angle deposition (GLAD) technique without a need for a catalyst. The cross-sectional field emission scanning electron microscopy (FESEM) image and energy-dispersive X-ray spectroscopy (EDS) confirm the successful adornment of Ag NP and Au NP on the top surface of MnO 2 NW. Elemental mapping has verified the presence of manganese (Mn), oxygen (O), silicon (Si), Ag, and Au within the sample. X-ray diffraction (XRD) patterns reveal the polycrystalline growth of the MnO 2 film with the preferred orientation. AFM reveals that the surface roughness of Au NP/MnO 2 NW is more than Ag NP/MnO 2 NW. The measured water contact angles of Au NP/MnO 2 NW, Ag NP/MnO 2 NW, and MnO 2 NW were 125° and 113°, respectively. Ag NP/MnO 2 NW showed more hydrophilic properties under UV illumination than Au NP/MnO 2 NW owing to the efficient separation of photogenerated electron–hole pairs. Ag NP/MnO 2 NW’s higher photocatalytic activity than Au NP/MnO 2 NW is attributed to the increased light absorption of the Ag NP in the UV region. The overall enhancement after decorating the noble metal NP on MnO 2 NW could open new avenues for self-cleaning applications.