Contents lists available at ScienceDirect Ceramics International journal homepage: www.elsevier.com/locate/ceramint Construction of Au/TiO 2 Heterojunction with high photocatalytic performances under UVA illumination L.A. Al-Hajji a , Adel A. Ismail a,∗ , A. Bumajdad b , M. Alsaidi a , S.A. Ahmed a , F. Almutawa a , A. Al-Hazza a a Nanotechnologyand Advanced Materials Program, Energy & Building Research Center, Kuwait Institute for Scientific Research (KISR), P.O. Box 24885, Safat, 13109, Kuwait b Chemistry Department, Faculty of Science, Kuwait University, PO Box 5969, Safat, 13060, Kuwait ARTICLEINFO Keywords: Au NPs TiO 2 NPs Surface plasmon resonance Resorcinol Heterojunction ABSTRACT Anatase TiO 2 nanoparticles (NPs) were successfully prepared through a hydrothermal approach, and Au NPs at various Au (0.1–2 wt%) contents were photodeposited onto the TiO 2 NPs surface. The photocatalytic efciency for the Au/TiO 2 NPs for resorcinol photodegradation throughout UVA illumination was assessed. The TEM images and XPS fndings indicated that the Au NPs are highly distributed onto TiO 2 surface in the metallic state. The 0.1%Au/TiO 2 NPs exhibited the highest photocatalytic efciency of about 95.34%; however, 72.36% is given by pure TiO 2 NPs. It was found that the photodegradation rate of 0.1% Au/TiO 2 NPs exhibited 1.5 times of magnitude higher than pure TiO 2 NPs. 0.1%Au/TiO 2 NPs was considered to be the outstanding photoactive due to the ultimate efcient charge-carriers separation through charge transfer between Au and TiO 2 NPs. The Au NPs sizes, its dispersity on TiO 2 surface and surface plasmon resonance (SPR) were believed the critical factors for the higher photocatalytic performance of 0.1% Au/TiO 2 NPs. The prepared photocatalysts are found to be the promising materials for toxic organic compounds remediation and solar conversion. 1. Introduction At the last decade, TiO 2 as a photocatalyst has received excellent research attention owing to its possible implementations in sustainable energy to generate H 2 and environmental treatment. Its photostability, non-toxicity, high photoactivity, and recycle ability was found to be the ultimately favourable photocatalysts for potential application [1–5]. The light energy is converted to chemical energy over the synthesized photocatalysts in the presence of UV, solar and visible lights. The photocatalysts efciency for energy conversion accurately bases on its ability to generate stable photogenerated charge carriers upon they harvest energy photons higher than the bandgap energy. The dis- advantage of TiO 2 photocatalyst is it's a broad bandgap energy ~3.3 ± 0.1 eV, and thus it can only harvest UV light, and they only absorb a slightly around 2–3% fraction of the solar light that reaches the surface of the earth. The TiO 2 photocatalytic experiments could not accomplish whenever using of solar light as an energy source [6–9]. Moreover, the strong recombination rate of photogenerated charge carriers of TiO 2 often creates in lack of photocatalytic performance. To explore the enhancement of the photocatalyst performance, both the charge carriers separation and light harvest should be addressed. Considerable eforts are dedicated to extending the TiO 2 photoresponse to more extensive wavelength regions, to create the employ of solar simulator much efectively for potential applications [6–9] Doping of TiO 2 is considered one of the most avenues to reduce its the bandgap energy, as a result expanding the visible region to promote the photo- response [10–12]. Notwithstanding, the metal ions doping integration into TiO 2 network creates the upgrowth of sub-bandgaps, intensive the deleterious charge carriers recombination. In eforts to prohibit the recombination of photo-induced electrons and holes, the creation of Schottky junction among metal and semiconductor appears a model path to trap holes or electrons on the metal [14], which generally conjugates the semiconductor and noble metals system. Besides, pre- cious metals like Au and Ag NPs exhibited outstanding surface plas- monic characteristics in the wide visible light range, which could be developed the utilization of energy in a broad range [15–18]. The surface plasmon is enhanced separation/generation the charge carriers through two various mechanisms: i) the enhancement of local electro- magnetic feld to boost the transition rate interband of semiconductor, and ii) the plasmonic dipoles generate resonant energy transfer to the charge carriers in the metal oxides through the interaction of a near- feld electromagnetic [19–22]. https://doi.org/10.1016/j.ceramint.2020.05.093 Received 15 April 2020; Received in revised form 6 May 2020; Accepted 8 May 2020 ∗ Corresponding author.. E-mail address: aaismail@kisr.edu.kw (A.A. Ismail). Ceramics International xxx (xxxx) xxx–xxx 0272-8842/ © 2020 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Please cite this article as: L.A. Al-Hajji, et al., Ceramics International, https://doi.org/10.1016/j.ceramint.2020.05.093