Journal of Physics and Chemistry of Solids 148 (2021) 109704 Available online 21 August 2020 0022-3697/© 2020 Published by Elsevier Ltd. Fabrication of Pd nanoparticles on Al substrate with excellent superhydrophobicity and photocatalytic activity Noor Hassan, Shixiang Lu * , Wenguo Xu ** , He Ge, Muhammad Adnan Naseer, Muhammad Zahid, Asia Sultana, Waqar Azeem Khan School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, PR China A R T I C L E INFO Keywords: Superhydrophobic Annealing Nanoparticle Aluminum Palladium Photodegradation ABSTRACT A stable palladium superhydrophobic surface (PdSHS) with static water contact angle of 161 ± 1 ◦ and sliding angle of 2 ◦ was fabricated on aluminum (Al) substrate through etching, deposition, and anneal process. The chemical composition, surface texture, and morphology were tested by X-ray diffraction pattern, X-ray photo- electron spectroscopy, scanning electron microscopy, along with energy dispersive spectroscopy. Pd nano- particles were organized on micro and nanoscale on rough Al substrate. The electrochemical impedance spectroscopy was explored to test anti-corrosion behavior of PdSHS that is enhanced signifcantly than that of Al substrate. The environmental stability, durability and large size of PdSHS are also investigated with satisfactoried results. The photodegradation rate, chemical reaction constant and half-life of methylene blue are 98.31%, 5.89 × 10 2 s 1 , and 5.27 min respectively when the PdSHS was as photocatalyst, which is much better than that of superhydrophilic sample. The photocatalytic degrading profciency of PdSHS remains relatively stable even after 11 cycles. These can enhance industrial applications of the Pd nanoparticles on Al substrate and its alloys. 1. Introduction Recent decades, superhydrophobic surfaces (SHSs) have been attracting the attention of researchers because of various accessible applications, for example, corrosion resistance [1], antifogging [2], self-cleaning [3], oil/water separation [4–6], anti-icing [7], catalytic reduction [8], photocatalysis [9], anti-biofouling [10], biomedicine [11], anti-bacterial [12], drag reduction [13], sensing [14], Hydrogen Energy [15–17] and super buoyancy [18]. SHSs have been designed by various techniques, such as, templating [19], sol-gel methods [20], lithographic techniques [21], electrospinning [22], casting method [23], chemical vapor deposition [24], chemical etching [25], layer by layer stacking [26], Spray-Deposition [27] and a dip-coating method [28]. However, challenging strategies required to create perfect SHSs for fruitful applications. Dip-coating, spray coating and brush-coating are the routine synthetic techniques that can promote the practical use of SHSs. The mechanical durability of such SHSs composed of micro-scaled/hierarchical nanostructures decreased on the non-metallic substrate and the risk of carcinogenic (aromatic hydrocarbons) con- taminations through such body surfaces increased [29,30]. So fabrication of SHSs on metallic substrates without any organic modif- cation has been paid more attention [31]. The photodegradation of industrial pollutants under sunlight has been drawn much interest [9]. Researchers and pharmacists have done effort into industrial development, and as a result, the contaminated water sources are unexpectedly increasing. The fuid wastes released from textiles pigments, paper printings, and many other chemical in- dustries discharged directly or indirectly in the open environment without necessary treatment [32]. Among different known carcinogenic aromatic hydrocarbons, aromatic hydrocarbons, dyestuff, especially rhodamine, congo red, eriochrome black T, and methylene blue (MB). These are highly harmful to aquatic life and living organisma [33]. Palladium (Pd) nanoparticles (NPs) have been broadly used in various felds due to generally accessible, economical, eco-friendly, and high stability in the open air [34]. A suitable method to photodegrade the industrial waste through the catalyst is the accommodation of Pd NPs by various methods on the substrate surfaces, for example, Pd doped with nonmetal component and other metallic oxides. Unfortunately, the method used for the doping components not controlled, and a smaller number of particles of these combinations limits the applications [35]. * Corresponding author. ** Corresponding author. E-mail addresses: shixianglu@bit.edu.cn (S. Lu), xuwg60@bit.edu.cn (W. Xu). Contents lists available at ScienceDirect Journal of Physics and Chemistry of Solids journal homepage: http://www.elsevier.com/locate/jpcs https://doi.org/10.1016/j.jpcs.2020.109704 Received 6 May 2020; Received in revised form 30 July 2020; Accepted 8 August 2020