Heterogeneous photocatalysis is vital in solving energy and environmental issues that this society is confronted with. Although photocatalysts are often operated in the presence of water, it has not been yet clarified how the interaction with water itself affects charge dynamics in photocatalysts. Using water-coverage-controlled steady and transient infrared absorption spectroscopy and large-model (~800 atoms) ab initio calculations, we clarify that water enhances hole trapping at the surface of TiO2 nanospheres but not of well-faceted nanoparticles. This water-assisted effect unique to the nanospheres originates from water adsorption as a ligand at a low-coordinated Ti-OH site or through robust hydrogen bonding directly to the terminal OH at the highly curved nanosphere surface. Thus, the interaction with water at the surface of nanospheres can promote photocatalytic reactions of both oxidation and reduction by elongating photogenerated carrier lifetimes. This morphology-dependent water-assisted effect provides a novel and rational basis for designing and engineering nanophotocatalyst morphology to improve photocatalytic performances

Shirai, K., Fazio, G., Sugimoto, T., Selli, D., Ferraro, L., Watanabe, K., et al. (2018). Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO2Photocatalyst. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 140(4), 1415-1422 [10.1021/jacs.7b11061].

Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO2Photocatalyst

Fazio, Gianluca
Co-primo
;
Selli, Daniele;Ferraro, Lorenzo;Di Valentin, Cristiana
Penultimo
;
2018

Abstract

Heterogeneous photocatalysis is vital in solving energy and environmental issues that this society is confronted with. Although photocatalysts are often operated in the presence of water, it has not been yet clarified how the interaction with water itself affects charge dynamics in photocatalysts. Using water-coverage-controlled steady and transient infrared absorption spectroscopy and large-model (~800 atoms) ab initio calculations, we clarify that water enhances hole trapping at the surface of TiO2 nanospheres but not of well-faceted nanoparticles. This water-assisted effect unique to the nanospheres originates from water adsorption as a ligand at a low-coordinated Ti-OH site or through robust hydrogen bonding directly to the terminal OH at the highly curved nanosphere surface. Thus, the interaction with water at the surface of nanospheres can promote photocatalytic reactions of both oxidation and reduction by elongating photogenerated carrier lifetimes. This morphology-dependent water-assisted effect provides a novel and rational basis for designing and engineering nanophotocatalyst morphology to improve photocatalytic performances
Articolo in rivista - Articolo scientifico
Nanoparticles; Photocatalysis; Titanium dioxide; Density Functional Theory; Transient Adsorption Spectroscopy; Water; Catalysis; Chemistry (all); Biochemistry; Colloid and Surface Chemistry
English
2018
140
4
1415
1422
partially_open
Shirai, K., Fazio, G., Sugimoto, T., Selli, D., Ferraro, L., Watanabe, K., et al. (2018). Water-Assisted Hole Trapping at the Highly Curved Surface of Nano-TiO2Photocatalyst. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 140(4), 1415-1422 [10.1021/jacs.7b11061].
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