{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,23]],"date-time":"2025-12-23T10:43:31Z","timestamp":1766486611580,"version":"build-2065373602"},"reference-count":30,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2024,9,20]],"date-time":"2024-09-20T00:00:00Z","timestamp":1726790400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Portuguese Foundation for Science and Technology FCT\/MCTES","doi-asserted-by":"publisher","award":["PTDC\/FIS-MAC\/6606\/2020","UIDB\/04650\/2020","UIDB\/04029\/2020","LA\/P\/0112\/2020","2023.02795.BD","PRT\/BD\/154269\/2022","2022.00763.CEECIND"],"award-info":[{"award-number":["PTDC\/FIS-MAC\/6606\/2020","UIDB\/04650\/2020","UIDB\/04029\/2020","LA\/P\/0112\/2020","2023.02795.BD","PRT\/BD\/154269\/2022","2022.00763.CEECIND"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT\u2014Foundation for Science and Technology","doi-asserted-by":"publisher","award":["PTDC\/FIS-MAC\/6606\/2020","UIDB\/04650\/2020","UIDB\/04029\/2020","LA\/P\/0112\/2020","2023.02795.BD","PRT\/BD\/154269\/2022","2022.00763.CEECIND"],"award-info":[{"award-number":["PTDC\/FIS-MAC\/6606\/2020","UIDB\/04650\/2020","UIDB\/04029\/2020","LA\/P\/0112\/2020","2023.02795.BD","PRT\/BD\/154269\/2022","2022.00763.CEECIND"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Photonics"],"abstract":"<jats:p>This study investigates the effect of iron-modified nano-TiO2, using the co-precipitation method with different concentrations of FeCl3 (0.1, 1, and 10%), to improve its photocatalytic properties for outdoor applications. To this end, modified and unmodified nano-TiO2 were characterized using different techniques. The optical properties were characterized by diffuse reflectance spectroscopy (DRS) followed by band gap calculation. X-ray diffraction (XRD) was used to analyze the crystalline structure. Chemical and morphological characterization were carried out using energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The photocatalytic activity was investigated by decolorizing Rhodamine B aqueous solutions under similar sunlight irradiation. The results indicate that the modification improved light absorption in the UV range for all iron concentrations; however, only the concentration of TiO2: FeCl3 (10%) shifted the absorption to the visible region. Also, including Fe3\u207a in TiO2 decreased the band gap energy from 3.14 to up to 2.80 eV. There were variations in crystallite size from 21.13 to up to 40.07 nm. The nano-TiO2 morphology analysis showed that it did not change after iron modification. EDS showed an FeCl3 peak only at higher concentrations (10%). In addition, the 0.1% Fe-modified TiO2 exhibited the highest activity in the photocatalytic process, with an efficiency of 95.23% after 3 h of irradiation.<\/jats:p>","DOI":"10.3390\/photonics11090888","type":"journal-article","created":{"date-parts":[[2024,9,20]],"date-time":"2024-09-20T10:49:48Z","timestamp":1726829388000},"page":"888","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Iron-Modified Nano-TiO2: Comprehensive Characterization for Enhanced Photocatalytic Properties"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6649-4029","authenticated-orcid":false,"given":"\u00c9lida M.","family":"Margalho","sequence":"first","affiliation":[{"name":"Centre of Physics of Minho and Porto Universities (CF-UM-UP), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"},{"name":"ARISE, Department of Civil Engineering (ISISE-UMinho), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5702-006X","authenticated-orcid":false,"suffix":"Jr.","given":"Orlando","family":"Lima","sequence":"additional","affiliation":[{"name":"Centre of Physics of Minho and Porto Universities (CF-UM-UP), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"},{"name":"ARISE, Department of Civil Engineering (ISISE-UMinho), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"}]},{"given":"C\u00e1tia","family":"Afonso","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4199-5994","authenticated-orcid":false,"given":"Iran Rocha","family":"Segundo","sequence":"additional","affiliation":[{"name":"Centre of Physics of Minho and Porto Universities (CF-UM-UP), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1830-7548","authenticated-orcid":false,"suffix":"Jr.","given":"Salmon","family":"Landi","sequence":"additional","affiliation":[{"name":"Federal Institute Goiano, Rio Verde Campus, Rio Verde 75901-970, GO, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5132-7407","authenticated-orcid":false,"given":"Elisabete","family":"Freitas","sequence":"additional","affiliation":[{"name":"ARISE, Department of Civil Engineering (ISISE-UMinho), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1554-8779","authenticated-orcid":false,"given":"Manuel F. M.","family":"Costa","sequence":"additional","affiliation":[{"name":"Centre of Physics of Minho and Porto Universities (CF-UM-UP), Gualtar Campus, University of Minho, R. da Universidade, 4710-057 Braga, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9778-5390","authenticated-orcid":false,"given":"Joaquim","family":"Carneiro","sequence":"additional","affiliation":[{"name":"Centre of Physics of Minho and Porto Universities (CF-UM-UP), University of Minho, Av. da Universidade, 4800-058 Guimar\u00e3es, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,9,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Lale, E., Uyguner-Demirel, C.S., and Bekbolet, M. (2024). Visible Light Photocatalytic Response of Fe Doped TiO2: Inactivation of Escherichia Coli. J. Photochem. Photobiol. A Chem., 456.","DOI":"10.1016\/j.jphotochem.2024.115836"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"111552","DOI":"10.1016\/j.rser.2021.111552","article-title":"Review and Analysis of Advances in Functionalized, Smart, and Multifunctional Asphalt Mixtures","volume":"151","author":"Segundo","year":"2021","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Fang, M., Peng, L., Li, Y., Cheng, Y., and Zhan, L. (2022). Evaluation Test of NO Degradation by Nano-TiO2 Coatings on Road Pavements under Natural Light. Coatings, 12.","DOI":"10.3390\/coatings12081200"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Bersch, J.D., Pican\u00e7o Casarin, R., Maia, J., Masuero, A.B., and Dal Molin, D.C.C. (2023). TiO2-Based Mortars for Rendering Building Envelopes: A Review of the Surface Finishing for Sustainability. Sustainability, 15.","DOI":"10.3390\/su152416920"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Nyamukamba, P., Okoh, O., Mungondori, H., Taziwa, R., and Zinya, S. (2018). Synthetic Methods for Titanium Dioxide Nanoparticles: A Review. Titanium Dioxide\u2014Material for a Sustainable Environment, InTech.","DOI":"10.5772\/intechopen.75425"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"9919","DOI":"10.1021\/cr5001892","article-title":"Understanding TiO2 Photocatalysis: Mechanisms and Materials","volume":"114","author":"Schneider","year":"2014","journal-title":"Chem. Rev."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"16550","DOI":"10.1007\/s10854-022-08547-5","article-title":"Solar-Light-Induced Photocatalyst Based on Bi\u2013B Co-Doped TiO2 Prepared via Co-Precipitation Method","volume":"33","author":"Sangeetha","year":"2022","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"7476","DOI":"10.1007\/s10853-014-8453-3","article-title":"Synthesis of Iron-Doped TiO2 Nanoparticles by Ball-Milling Process: The Influence of Process Parameters on the Structural, Optical, Magnetic, and Photocatalytic Properties","volume":"49","author":"Carneiro","year":"2014","journal-title":"J. Mater. Sci."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"3088","DOI":"10.1016\/j.ceramint.2015.10.097","article-title":"The Effects of Fe, Co and Ni Dopants on TiO2 Structure of Sol\u2013Gel Nanopowders Used as Photocatalysts for Environmental Protection: A Comparative Study","volume":"42","author":"Ianculescu","year":"2016","journal-title":"Ceram. Int."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Matias, M.L., Pimentel, A., Reis-Machado, A.S., Rodrigues, J., Deuermeier, J., Fortunato, E., Martins, R., and Nunes, D. (2022). Enhanced Fe-TiO2 Solar Photocatalysts on Porous Platforms for Water Purification. Nanomaterials, 12.","DOI":"10.3390\/nano12061005"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"015022","DOI":"10.1088\/2053-1591\/aa576d","article-title":"Photocatalytic Performance of Fe-Doped TiO2 Nanoparticles under Visible-Light Irradiation","volume":"4","author":"Ali","year":"2017","journal-title":"Mater. Res. Express"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"143","DOI":"10.4186\/ej.2012.16.3.143","article-title":"Highly Efficient Visible-Light-Induced Photocatalytic Activity of Fe-Doped TiO2 Nanoparticles","volume":"16","author":"Pongwan","year":"2012","journal-title":"Eng. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"27","DOI":"10.1016\/j.apcatb.2007.11.041","article-title":"Synthesis, Structure and Photocatalytic Properties of Fe(III)-Doped TiO2 Prepared from TiCl3","volume":"81","author":"Ambrus","year":"2008","journal-title":"Appl. Catal. B Environ."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1186\/s44147-023-00178-9","article-title":"Doping TiO2 with Fe from Iron Rusty Waste for Enhancing Its Activity under Visible Light in the Congo Red Dye Photodegradation","volume":"70","author":"Wahyuni","year":"2023","journal-title":"J. Eng. Appl. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Afonso, C., Lima, O., Segundo, I.R., Landi, S., Margalho, \u00c9., Homem, N., Pereira, M., Costa, M.F.M., Freitas, E., and Carneiro, J. (2022). Effect of Iron-Doping on the Structure and Photocatalytic Activity of TiO2 Nanoparticles. Catalysts, 13.","DOI":"10.3390\/catal13010058"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"590","DOI":"10.1016\/j.jhazmat.2007.11.095","article-title":"Effect of Fe-Doped TiO2 Nanoparticle Derived from Modified Hydrothermal Process on the Photocatalytic Degradation Performance on Methylene Blue","volume":"155","author":"Li","year":"2008","journal-title":"J. Hazard. Mater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.apcata.2009.12.023","article-title":"The Advancements in Sol\u2013Gel Method of Doped-TiO2 Photocatalysts","volume":"375","author":"Akpan","year":"2010","journal-title":"Appl. Catal. A Gen."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Letifi, H., Dridi, D., Litaiem, Y., Ammar, S., Dimassi, W., and Chtourou, R. (2021). High Efficient and Cost Effective Titanium Doped Tin Dioxide Based Photocatalysts Synthesized via Co-Precipitation Approach. Catalysts, 11.","DOI":"10.3390\/catal11070803"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1071","DOI":"10.1007\/s41742-021-00372-8","article-title":"Ultrasound-Assisted Synthesis of Fe-Doped TiO2 Catalyst for Photocatalytic Oxidation Application","volume":"15","author":"Mahendran","year":"2021","journal-title":"Int. J. Environ. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.apcatb.2015.05.003","article-title":"Effect of Fe on the Photocatalytic Removal of NO over Visible Light Responsive Fe\/TiO2 Catalysts","volume":"179","author":"Ma","year":"2015","journal-title":"Appl. Catal. B Environ."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"112","DOI":"10.1016\/j.cemconres.2012.09.007","article-title":"Incorporation of Titanium Dioxide Nanoparticles in Mortars\u2014Influence of Microstructure in the Hardened State Properties and Photocatalytic Activity","volume":"43","author":"Lucas","year":"2013","journal-title":"Cem. Concr. Res."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"457","DOI":"10.2174\/138527206776055330","article-title":"Recent Uses of Iron (III) Chloride in Organic Synthesis","volume":"10","author":"Miranda","year":"2006","journal-title":"Curr. Org. Chem."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1189","DOI":"10.1007\/s10854-017-8021-0","article-title":"Studies on Electrical Behavior of Fe Doped ZnO Nanoparticles Prepared via Co-Precipitation Approach for Photo-Catalytic Application","volume":"29","author":"Jeyachitra","year":"2018","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"605","DOI":"10.1007\/s41742-020-00280-3","article-title":"Coprecipitation Synthesis of Fe-Doped TiO2 from Various Commercial TiO2 for Photocatalytic Reaction","volume":"14","author":"Ellouzi","year":"2020","journal-title":"Int. J. Environ. Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"355602","DOI":"10.1088\/0957-4484\/21\/35\/355602","article-title":"Controlled Synthesis of Single-Crystalline \u03b1-Fe2O3 Micro\/Nanoparticles from the Complex Precursor of FeCl3 and Methyl Orange","volume":"21","author":"Yang","year":"2010","journal-title":"Nanotechnology"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"114573","DOI":"10.1016\/j.ssc.2021.114573","article-title":"Use and Misuse of the Kubelka-Munk Function to Obtain the Band Gap Energy from Diffuse Reflectance Measurements","volume":"341","author":"Landi","year":"2022","journal-title":"Solid State Commun."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"760","DOI":"10.1021\/ac60125a006","article-title":"Quantitative Analysis of Anatase-Rutile Mixtures with an X-Ray Diffractometer","volume":"29","author":"Spurr","year":"1957","journal-title":"Anal. Chem."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"5309","DOI":"10.1007\/s10853-014-8234-z","article-title":"Synthesis, Characterization, Photocatalytic Evaluation, and Toxicity Studies of TiO2\u2013Fe3+ Nanocatalyst","volume":"49","author":"Liu","year":"2014","journal-title":"J. Mater. Sci."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2205","DOI":"10.1016\/j.apsusc.2008.07.079","article-title":"Synthesis and Characterization of TiO2 and Fe\/TiO2 Nanoparticles and Their Performance for Photocatalytic Degradation of 1,2-Dichloroethane","volume":"255","author":"Hung","year":"2008","journal-title":"Appl. Surf. Sci."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"10871","DOI":"10.1021\/jp982948+","article-title":"Role of Particle Size in Nanocrystalline TiO2-Based Photocatalysts","volume":"102","author":"Zhang","year":"1998","journal-title":"J. Phys. Chem. B"}],"container-title":["Photonics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2304-6732\/11\/9\/888\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:01:13Z","timestamp":1760112073000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2304-6732\/11\/9\/888"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,9,20]]},"references-count":30,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2024,9]]}},"alternative-id":["photonics11090888"],"URL":"https:\/\/doi.org\/10.3390\/photonics11090888","relation":{},"ISSN":["2304-6732"],"issn-type":[{"type":"electronic","value":"2304-6732"}],"subject":[],"published":{"date-parts":[[2024,9,20]]}}}