Surface Defect Engineering in Colored TiO₂ Hollow Spheres Toward Efficient Photocatalysis

Abstract

Nanostructured TiO 2 is one of the best materials for photocatalysis, thanks to its high surface area and surface reactivity, but its large energy bandgap (3.2 eV) hinders the use of the entire solar spectrum. Here, it is proposed that defect-engineered nanostructured TiO 2 photocatalysts are obtained by hydrogenation strategy to extend its light absorption up to the near-infrared region. It is demonstrated that hydrogenated or colored TiO 2 hollow spheres (THS) composed of hierarchically assembled nanoparticles result in much broader exploitation of the solar spectrum (up to 1200 nm) and the engineered surface enhances the photogeneration of charges for photocatalytic processes. In turn, when applied for photodegradation of a targeted drug (Ciprofloxacin) this results in 82% degradation after 6 h under simulated sunlight. Valence band analysis by photoelectron spectroscopy revealed the presence of oxygen vacancies, whose surface density increases with the hydrogenation rate. Thus, a tight correlation between degree of hydrogenation and photocatalytic activity is directly established. Further insight comes from electron paramagnetic resonance, which evidences bulk Ti 3+ centers only in hydrogenated THS. The results are anticipated to disclose a new path toward highly efficient photocatalytic titania in a series of applications targeting water remediation and solar fuel production.

Photocatalytic one-pot alkylation of nitrobenzene with benzyl alcohol for the precise synthesis of N-benzylideneaniline over F-doped Bi2MoO6 nanosheets

“…All of the prepared samples are perfectly matched with orthorhombic phase Bi 2 MoO 6 (JCPDS# 21-0102), indicating the successful synthesis of the catalysts with fine crystallinity. 26 Compared with the BMO-NSs, BMO-B shows sharper and narrower diffraction peaks, suggesting the formation of the characteristic nanostructure. Moreover, no obvious peaks related to F were observed (Fig.…”

Internal Electric Field-Modulated S-Scheme Ni3Se4/TiO2 Nanoparticle Heterojunction for Efficient Photocatalytic H2 Evolution

“…Since 1972, Honda and Fujishima discovered TiO 2 for photoelectrochemical water splitting under ultraviolet light irradiation, TiO 2 has been widely investigated for its cost-effectiveness, nontoxicity, and stability. − However, there are still obstacles including severe charge recombination, weak visible light absorption ability, lack of active sites, and sluggish surface reaction kinetics that hindered the practical application of TiO 2 . − Therefore, rational strategies to improve the activity of TiO 2 are indispensable for the development of efficient photocatalytic systems.…”

Charge-enriched RuO2 nanoparticles decorating TiO2 with Ti defects to promote oxygen evolution reaction in acidic media

“…Currently, typical TiO 2 is a favored material for its wide range of applications in the fields of environmental solar fuel, photocatalysis, and energy storage. [37][38][39][40] Alternatively, TiO 2 is a suitable candidate for dispersing RuO 2 nanoparticles because of its strong corrosion resistance. However, the poor electronic conductivity and slow charge transport properties of pristine TiO 2 seriously limit its application as an electrocatalyst support.…”