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Invited speaker during the 13th international NanoTech Poland conference in Poznań — Juan Carlos Colmenares 


Professor Juan Carlos Colmenares was extended a prestigious invitation to serve as an INVITED SPEAKER at the 13th international NanoTech Poland conference with a topic of:

  • Nanostructured unsupported and carbon-supported titanium (hydro)dioxides for photocatalytic organic synthesis: mechanistic insights by experimental and computational studies

All authors: Juan Carlos Colmenares, Dimitrios A. Giannakoudakis, Abdul Qayyum, Ayesha Khan and Dariusz Łomot

The esteemed conference took place from 14th to 16th June 2023 in Poznań, Poland. This highly anticipated annual event, organized since 2011 by the esteemed NanoBioMedical Centre at Adam Mickiewicz University, showcased cutting-edge technology and science advancements.

The conference provided a diverse scientific program and served as a global platform for in-depth discussions on the latest breakthroughs and challenges in the field of nanoscience and nanotechnology.

The conference spotlighted a wide range of disciplines, including applications in energy, electronics, environment, and biomedicine. Distinguished lectures were conducted in two parallel topic sections, with Section A devoted to the exploration of advanced nanomaterials

Invited speaker during the 13th international NanoTech Poland conference in Poznań - Juan Carlos Colmenares


The investigation for greener” and economically feasible approaches such as photocatalysis for the selective transformation of organic-waste-derived compounds like aromatic alcohols by avoiding the drastic reaction conditions/​reagents have concentrated the focus of attention of the last years [1,2,3]. The design and fabrication of novel photocatalysts for organic synthesis are very challenging. In this research work [1,3], the synthesis of TiO2-based and carbon-supported TiO2 were performed by the ultrasound-assisted via precipitation, and sol-gel-based hydrosolvothermal methods, respectively.

The additive-free photoactivity showed that TiO2 and TiO2-containing carbophotocatalytsts revealed the highest yield of the target product than commercial TiO2 and g-C3N4. The physicochemical features of the most promising materials were determined by N2 sorption, HR-TEM, XPS, XRD, EDX, among other techniques. Novel nanostructured titanium based as it is, and also immobilized on chitosan-lignin-based carbon supports, are very promising materials for the additives-free selective partial oxidation of benzyl alcohol BnOH (a biomass model compound) to benzaldehyde (PhCHO) at ambient conditions under low-power ultraviolet (365 nm) or royal-blue (465 nm) light irradiation.

DFT calculations in combination with the detailed physicochemical features as well as various scavengers’ tests, revealed that the photo-oxidation of BnOH can be achieved via different mechanisms and with different reactive oxygen species to be involved, depending on the catalyst’s physicochemical feature and the nature of light. The diluted molecular oxygen and the photo-induced holes play a crucial role in the selective oxidation of BnOH, while the formation of free hydroxyl radicals has a negative impact since they are responsible for non-selective reactions. BnOH is adsorbed differently on the surface, bridging oxygen vacancies compared to the hydroxyl groups, affecting the antenna/​photosensitization effect.


This research is partially supported by the National Science Centre (NCN) in Poland within research projects OPUS 20 No. 2020/39/B/ST5/00076, and OPUS-13 no. 2017/25/B/ST8/01592.


  1. D.A. Giannakoudakis, A.Qayyum, M. Barczak, R.F. Colmenares-Quintero, P. Borowski, K. Triantafyllidis, J.C. Colmenares. Applied Catalysis B: Environmental (2023), 320, 121939.
  2. A. Qayyum, D.A. Giannakoudakis, A.P. LaGrow, O. Bondarchuk, D. Łomot, J.C. Colmenares. Catalysis Communications, (2022). DOI: 10.1016/j.catcom.2022.106406.
  3. A. Khan, M. Goepel, W. Lisowski, D. Łomot, D. Lisovytskiy, M. Mazurkiewicz-Pawlicka, R. Glaser, Magdalena Warczak, J.C. Colmenares. RSC Advances (2021), 11, 34996 – 35010.

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