@article{fb812e8e12574e50b6ec5ccbde7eb0d7,
title = "Functionalization of TiO2 inverse opal structure with atomic layer deposition grown Cu for photocatalytic and antibacterial applications",
abstract = "TiO2 inverse opal (IO) structure surfaces were functionalized with a sub-monolayer amount of Cu by atomic layer deposition (ALD) and tested for photocatalytic and antimicrobial applications. Decomposition of acetylene (C2H2) into CO2 and reduction of CO2 into CH4 were tested in the gas phase and photodegradation of methylene blue (MB) was tested in the liquid phase. Antimicrobial activity was tested against Gram-positive Staphylococcus aureus (S. aureus) bacteria. ALD Cu without any post-deposition heat treatment (HT) decreased the photo degradation rate of both C2H2 and MB but improved the activity towards CO2 reduction. ALD Cu increased MB photodegradation rate and antimicrobial activity only after HT at 550 °C, which was linked to the improved chemical stability Cu after the HT. The same HT decreased the activity towards CO2 reduction and decomposition of C2H2. The HT induced desorption of loosely bound ALD Cu+/2+ from the TiO2 IO surface and the remaining Cu+/2+ was reduced to Cu+. The photocatalytic and antimicrobial activity of TiO2 IO can be tailored by the addition of a sub-monolayer amounts of Cu with performance depending on the targeted reaction.",
keywords = "Antimicrobial activity, Atomic layer deposition (ALD), CO reduction, Cu, Inverse opal, Photocatalytic activity, TiO",
author = "Khai Pham and Harri Ali-L{\"o}ytty and Jesse Saari and Muhammad Zubair and Mika Valden and Kimmo Lahtonen and Niko Kinnunen and Marianne Gunell and Saarinen, {Jarkko J.}",
note = "Funding Information: K.P. wishes to thank UEF SCITECO doctoral program for a research position. J.S. was supported by The Vilho, Yrj{\"o} and Kalle V{\"a}is{\"a}l{\"a} Foundation of the Finnish Academy of Science and Letters . This work was supported by Jane & Aatos Erkko Foundation (Project {\textquoteleft}Solar Fuels Synthesis{\textquoteright}) and by Business Finland (TUTLi project {\textquoteleft}Liquid Sun{\textquoteright}) (Decision Number 1464/31/2019). JJS acknowledges the Academy of Finland funding (339 554). This work is part of the Academy of Finland Flagship Programme, Photonics Research and Innovation (PREIN) (Decision Numbers 320165 , 320166 ). Funding Information: Photocatalytic CO2 reduction tests in the gas-phase were performed using an in-house-built recirculating batch reactor comprising of a quartz photoreactor (250 ml photoelectrochemical cell, Pine Research, NC, USA), peristaltic pump (Masterflex, Cole-Parmer, IL, USA), gas chromatography unit with two gas sampling valves (Thermo scientific TRACE 1310, MA, USA), a flow meter (G Series, Swagelok, OH, USA), a pressure gauge (Baratron{\textregistered}, MKS Instruments, MA, USA), gas inlets and a vacuum pump (SH-110 Dry Scroll Vacuum Pump, Agilent Technologies, CA, USA). Before sealing the reactor, 10 ml ultrapure water (18.2 MΩ cm, Merck Milli-Q{\textregistered}) was added to the bottom of the photoreactor and a microscopy slide with the photocatalyst coating was supported in up-right position above the liquid. The reactor was then evacuated and filled with CO2 (99.99% CO2, Aga, Finland) in three repetitive cycles to remove all impurities from the system. The photoreactor was finally filled with 760 torr CO2 and kept it in dark for 30 min to guarantee the adsorption-desorption equilibrium. During the test, the gas was recirculated between the gas chromatography (GC) and the photoreactor with the peristaltic pump. The photocatalytic reaction was initiated by illuminating the photocatalyst (3.6 cm2 film area) by UVA light (300–400 nm, optical power of 51 mW/cm2) from the light source (MAX-350 equipped with UV–Vis mirror module and a 400 nm short pass filter XHS0400, Asahi Spectra Co., Ltd., Japan). After every 30 min, a gas-phase sample was injected to the GC via the two gas sampling valves (GSV) using N2 as the carrier gas in the GC. GSVs were connected to a thermal conductivity detector (TCD) and a flame ionization detector (FID) via TG-Bond Msieve 5A and TG-BOND Q 5A columns (Thermo scientific TRACE 1310, MA, USA), respectively. The GC response was calibrated before each test using a gas mixture consisting of O2, CO2, H2, CO, CH4, C2H4 and C2H6 (0.5 vol.-% each) in N2 (Linde plc, Ireland). Each test was performed for 2 h and the production rate was normalized to the illuminated surface area and time.K.P. wishes to thank UEF SCITECO doctoral program for a research position. J.S. was supported by The Vilho, Yrj{\"o} and Kalle V{\"a}is{\"a}l{\"a} Foundation of the Finnish Academy of Science and Letters. This work was supported by Jane & Aatos Erkko Foundation (Project {\textquoteleft}Solar Fuels Synthesis{\textquoteright}) and by Business Finland (TUTLi project {\textquoteleft}Liquid Sun{\textquoteright}) (Decision Number 1464/31/2019). JJS acknowledges the Academy of Finland funding (339 554). This work is part of the Academy of Finland Flagship Programme, Photonics Research and Innovation (PREIN) (Decision Numbers 320165, 320166). Publisher Copyright: {\textcopyright} 2022 The Authors",
year = "2022",
doi = "10.1016/j.optmat.2022.112695",
language = "English",
volume = "131",
journal = "Optical Materials",
issn = "0925-3467",
publisher = "Elsevier B.V.",
}