Photocatalytic removal of benzene over Ti3C2Tx MXene and TiO2-MXene composite materials under solar and NIR irradiation

abstract

MXenes, a family of two-dimensional (2D) transition metal carbides, nitrides and carbonitrides based on earth-abundant constituents, are prospective candidates for energy conversion applications, including photocatalysis. While the activity of individual MXenes towards various photocatalytic processes is still debatable, these materials were proved to be excellent co-catalysts, accelerating the charge separation and suppressing the exciton recombination. Titanium-containing MXenes are well compatible with the classical TiO2 photocatalyst. The TiO2 component can be directly grown on MXene sheets by in situ oxidation, representing a mainstream processing approach for such composites. In this study, an essentially different approach has been implemented: a series of TiO2-MXene composite materials with controlled composition and both reference end members were prepared, involving two different strategies for mixing sol-gel-derived TiO2 nanopowder with the Ti3C2Tx component, which was obtained by HF etching of self-propagating high-temperature synthesis products containing modified MAX phase Ti3C2Alz (z > 1) with nominal aluminium excess. The prospects of such composites for the degradation of organic pollutants under simulated solar light, using benzene as a model system, were demonstrated and analysed in combination with their structural, microstructural and optical properties. A notable photocatalytic activity of bare MXene under near infrared light was discovered, suggesting further prospects for light-to-energy harvesting spanning from UV-A to NIR and applications in biomedical imaging and sensors.

keywords

DEGRADATION; TIO2; MECHANISM; PHOTOCHROMISM; TI3ALC2; DESIGN; VAPOR

subject category

Materials Science; Physics

authors

Sergiienko, SA; Tobaldi, DM; Lajaunie, L; Lopes, DV; Constantinescu, G; Shaula, AL; Shcherban, ND; Shkepu, VI; Calvino, JJ; Frade, JR; Labrincha, JA; Kovalevsky, AV

Groups

G3 - Electrochemical Materials, Interfaces and Coatings
G4 - Renewable Materials and Circular Economy

Projects

SusPhotoSolutions - Soluções Fotovoltaicas Sustentáveis (SUSPHOTOSOLUTIONS)

Design de materiais termoeletricos avancados por efeitos redox: Progressos para aplicacoes de alta temperatura . (REMOTE)

CICECO - Aveiro Institute of Materials (UIDB/50011/2020)

CICECO - Aveiro Institute of Materials (UIDP/50011/2020)

Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)

acknowledgements

The authors acknowledge the support within the projects SusPhotoSolutions -Soluco~es Fotovoltaicas Sustenta ' veis (CENTRO-01-0145-FEDER-000005), REMOTE (POCI-01-0145FEDER-031875) and CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, and LA/P/0006/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. David Maria Tobaldi is overly grateful to FCT and to Portuguese national funds (OE), through FCT, I.P., in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. Luc Lajaunie acknowledges funding from the Andalusian regional government (FEDER-UCA-18-106613), the European Union's Horizon 2020 research and innovation program (grant agreement 823717 -ESTEEM3) and the Spanish Ministerio de Economia y Competitividad (PID2019-107578GA-I00). The authors also acknowledge the use of (S)TEM instrumentation provided by the National Facility ELECMI ICTS (``Division de Microscopia Electronica'', Universidad de Cadiz, DME-UCA). N. S. acknowledges the support of the Verkhovna Rada of Ukraine to a personal scholarship for young scientists -doctors of sciences for 2021.