In this study, carbon nanodots (C-dots)/WO3 photocatalysts were prepared via a two-step hydrothermal method. The morphologies and optical properties of the as-prepared materials were investigated. Compared with the prepared WO3 and C-dots, the C-dots/WO3 possessed stronger photocatalytic capability and excellent recyclability for photocatalytic elimination of Rhodamine B. For example, the achieved first order reaction rate constant of 0.01942 min-1 for C-dots/WO3 was ∼7.7 times higher than that of the prepared WO3. The enhanced photocatalytic activity of C-dots/WO3 was attributed to the enhanced light harvesting ability and efficient spatial separation of photo-excited electron-hole pairs resulting from the synergistic effect of WO3 and C-dots. The high photocatalytic activity of C-dots/WO3 remained unchanged even after 3 cycles of use. Meanwhile, a possible mechanism of C-dots/WO3 for the enhanced photocatalytic activity was proposed.

Two-step hydrothermally synthesized carbon nanodots/WO3 photocatalysts with enhanced photocatalytic performance

Carbon nanodots and rare metals (RM = La, Gd, Er) doped tungsten oxide nanostructures for photocatalytic dyes degradation and hydrogen production

Quantum dot-decorated semiconductor micro- and nanoparticles: A review of their synthesis, characterization and application in photocatalysis.

Achieving enhanced blue-light-driven photocatalysis using nanosword-like VO2/CuWO4 type II n–n heterojunction

Enhanced photocatalytic performance of visible-light active graphene-WO3 nanostructures for hydrogen production

Improved visible light photocatalytic activity of WO3 through CuWO4 for phenol degradation

The development of a highly active TiO2 photocatalyst for energy and environmental use is a great challenge. In this work, we report that the addition of sodium borate to an aqueous suspension of anatase TiO2 at neutral pH can result in a significant enhancement in the rate of phenol degradation. Similar results were also observed from 2,4-dichlorophenol degradation, spin-trapped OH radical formation, H2O2 decomposition, and chromate reduction in the presence of phenol. This borate-induced rate increase for phenol degradation was determined not only by the amount of borate adsorption but also by the structure of borate species (pH effect). A (photo)electrochemical measurement with the TiO2 film revealed that upon addition of borate, the hole consumption by phenol and the electron consumption by O2 were accelerated and decelerated, respectively. Moreover, the flat band potential of TiO2 was negatively shifted by 81 mV. Since the hole oxidation of water to O2 remained unchanged, it is proposed that a borate...

Borate-Mediated Hole Transfer from Irradiated Anatase TiO2 to Phenol in Aqueous Solution

PW12O40-type polyoxometalates have been widely used as electron mediators of TiO2 photocatalysis for organic degradation in water, but they are stable only at pH 1–2, which greatly limits their application for water treatment. Herein we report an iron(III)-substituted PW11O39 (PW11Fe) capable of mediating the photocatalytic degradation of phenol and 2,4-dichlorophenol in an aerated aqueous suspension of anatase TiO2 at pH 2.0–7.2. As the initial concentration of PW11Fe or the initial pH of the suspension increased, the rate of phenol degradation increased, and then decreased. A maximum reaction rate was achieved at 2.0 mM PW11Fe and pH 5.5, which was 3.9 times higher than that measured without PW11Fe. In all cases, the rates of phenol degradation were of the first order in phenol, implying the recycling behavior of PW11Fe. Through electrochemical measurement, a possible mechanism is proposed, which involves the interfacial electron transfer from the irradiated TiO2 to PW11Fe, and the reduction of O2 by the reduced PW11Fe. This would improve the efficiency of the charge separation of TiO2, and consequently increase the rate of phenol degradation at interfaces.

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Linlin Hao

Papers

Improved visible light photocatalytic activity of WO3 through CuWO4 for phenol degradation

Borate-Mediated Hole Transfer from Irradiated Anatase TiO2 to Phenol in Aqueous Solution

Enhanced photocatalytic degradation of phenol over anatase TiO2 in neutral water on addition of iron(III) substituted polyoxotungstate