Photocatalytic and photostability behavior of agand/ or Al-doped ZnO films in methylene blue and rhodamine B under UV-C irradiation

Adeel Riaz, Amna Ashraf, Hymna Taimoor, Sofia Javed, Muhammad Aftab Akram, Mohammad Islam, Mohammad Mujahid, Iftikhar Ahmad, Khalid Saeed

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number202
JournalCoatings
Volume9
Issue number3
DOIs
Publication statusPublished - 2019
Externally publishedYes

Keywords

  • Contact angle
  • Methylene blue
  • Photocatalysis
  • Photostability
  • Rhodamine B
  • Zinc oxide films

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