Photocatalytic and Photostability Behavior of Ag- and/or Al-Doped ZnO Films in Methylene Blue and Rhodamine B under UV-C Irradiation

Coatings

Mohammad Islam¹  Iftikhar Ahmad¹  Khalid Saeed²  Hymna Taimoor³  MuhammadAftab Akram³  Adeel Riaz³  Mohammad Mujahid³  Amna Ashraf³  Sofia Javed³ 

[1] Center of Excellence for Research in Engineering Materials (CEREM), Deanship of Scientific Research, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia;Department of Mechanical Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421, Saudi Arabia;School of Chemical and Materials Engineering, National University of Sciences and Technology, Islamabad 44000, Pakistan;

关键词: zinc oxide films;    photocatalysis;    methylene blue;    photostability;    contact angle;    rhodamine B;   

DOI  :  10.3390/coatings9030202

来源: DOAJ

【 摘 要 】

Silver (Ag) and/or aluminum (Al)-doped zinc oxide (ZnO:Ag, ZnO:Al) films with different concentrations were produced using sol-gel process and investigated for wettability and photocatalysis. Water contact angle (CA) measurements indicated the films to be hydrophilic with reduced solid/liquid interfacial surface energy upon metal doping. The films were highly transparent (>94%) with red or blue shift in the absorption edge depending on the dopant type (Ag or Al) owing to the Burstein–Moss effect. The ZnO:Ag and ZnO:Al films with 0.5 and 1.0 wt.% metal dopant showed high degradation efficiency in methylene blue (MB) solution under UV irradiation, mainly due to an increase in the photogenerated electron–hole pair recombination time and hydroxyl radicals (·OH) generation. The MB degradation followed pseudo-first-order reaction with maximum apparent reaction rate constant of 2.40 h⁻¹ for the 0.5 wt.% ZnO:Al film. ZnO films with 1.0 wt.% dopant demonstrated excellent photostability and recyclability even after several runs presumably due to reduced Zn²⁺ dissolution as well as blocking of the active surface area. ZnO:(Ag + Al) film containing 0.5 wt.% Al and Ag showed excellent UV photodegradation of MB and rhodamine blue (RhB) with high levels of photostability over five cycles.

【 授权许可】

Unknown