Engineered Zr/Zn/Ti oxide nanocomposite coatings for multifunctionality

Ultrathin coatings were deposited using RF magnetron sputtering from optimized nanocomposites of ZrO2, ZnO, and TiO2 synthesized by high energy ball milling process. The synthesized nanocomposites and sputtered thin films were subjected to various tests to study the alloys/coatings' multifunctional benefits for antibacterial activity, anti-corrosion, anti-reflection self-cleaning applications. [Display omitted] •For first time we report ZrO2/ZnO/TiO2 (Z2T) nanocomposite with multifunctional properties.•89% of photocatalytic degradation efficiency was observed.•Excellent antibacterial activity (80%) demonstrated on E. Coli K12.•The optical bandgap fluctuated between 3.54 eV and 3.70 eV with varying ZrO2 content.•Sputtered Z2T nanocoatings performed excellent anti-corrosive and self-cleaning property. Engineering metal oxides to achieve highly desirable properties can allow for multifunctionality and simultaneously enable antibacterial, anticorrosion, antireflection, and self-cleaning (A3S) potentials on a single surface. This study elucidates the improvements on the properties of ultrathin coating deposited using RF sputtering from optimized mechanically milled nanocomposites of zirconium dioxide (ZrO2), zinc oxide (ZnO), and titanium dioxide (TiO2), - Z2T. Optimizing the compositions, synthesis, and sputtering parameters reflected the improvements in the individual metal oxides' properties. The bandgap of sputter-coated nanocomposite films showed a red-shift, from 3.70 to 3.54 eV with varying Zr rich to Zr poor compositions, suggesting its anti-reflecting potential application layer in solar cells. The photocatalytic studies using TiO2 rich nanocomposite samples showed higher degradation efficiency of 89% under visible light, implying good antibacterial property on E-coli. Electrochemical impedance spectroscopy (EIS) analysis using a 3.5% NaCl solution demonstrated that Z2T films sputtered on stainless steel substrates produce an excellent protective anti-corrosion coating with a phase angle around −82°. The water contact angle measurements supported the superior hydrophobic feature as self-cleaning by repelling the impurities. Furthermore, density functional theory calculations complemented the experimental results. Thus, engineered Z2T nanocomposites can pave the way to design multifunctional coatings/alloys for unprecedented applications.