Hyper doping O acts as a nonradiative center and generates an intermediate band with F atoms, exhibiting efficient photocatalysis activities under visible/NIR light.
significantly enhances the photocatalytic oxygen evolution performance without any sacrificial reagent. Guan successfully synthesized a same Si/MgTiO 3 heterostructures, which performed a decent H 2 generation from pure water without any sacrificial reagents. [6] Moreover, metallic conduction can be achieved at the crystalline-amorphous homointerface via electronic interface reconstruction to enhance the electron transport. [7] Our group and Huang's group have previously reported the modified CeF 3 nanoparticles on photocatalytic degradation of organic pollutants under visible light. [8] To further modify the CeF 3 nanoparticles, this work purposes to establish a crystalline-amorphous structure for oxygen evolution with sacrificial reagent free. Fe-based oxide/(oxy)hydroxides have been exploited as promising catalysts for gas-evolution due to their narrow bandgap and environment friendliness. [9] Amorphous, αand β-FeOOH are three classical crystal structures of FeOOH for HER or OER catalysts. [10] Many crystalline FeOOH photocatalysts were fabricated to attain a remarkable hydrogen-evolution efficiency. Moreover, previous studies have reported that amorphous samples of FeOOH usually surpass that of crystalline counterparts on OER performance. [11] Conscious of this, amorphous FeOOH is anticipated that it may facilitate carriers separation and transfer to enhance photocatalytic oxygen-evolution effectively.Herein, we constructed CeF 3 /α-FeOOH nanohybrids by onestep hydrothermal method, and further used them for photocatalytic oxygen-evolution from water splitting. Amorphous α-FeOOH assures the charge-carrier transfer efficiently and builds crystalline-amorphous interface to form metalsemiconductor like structure. The CeF 3 /α-FeOOH nanohybrids performed significantly enhanced water oxidation activity compared with that of pure CeF 3 in the absence of sacrificial reagent. Furthermore, the photocatalyst is still stable after repeated cycling. As far as we know, this work is probably the best oxygen-evolution rate with sacrificial reagent free. Results and DiscussionThe approach to produce CeF 3 /α-FeOOH nanohybrids is a onestep process using the hydrothermal method under the condition of different Fe 3+ concentrations. The crystal structures of the CeF 3 /α-FeOOH nanohybrids are demonstrated by X-ray diffraction (XRD) patterns and Fourier transform infrared (FTIR) Water oxidation is a crucial step in photocatalytic water splitting, but it still remains a great challenge for its complex four-electron process. Herein, uniform CeF 3 /α-FeOOH nanohybrids are synthesized by one-step hydrothermal process. The obtained CeF 3 /α-FeOOH nanohybrids exhibit a significantly high photocatalytic oxygen-evolution activity with sacrifice reagent free. The optimal CeF 3 /α-FeOOH-400 nanohybrid reaches a remarkable rate up to 4702.5 µmol g −1 h −1 , which is 2.6 times higher than that of CeF 3 /α-FeOOH-0 nanohybrid. The recycling experiments further indicate its potential in oxygen evolution. The metal-like α-FeOOH may improve the...
The fabrication of heterojunctions or homojunctions between semiconductors is a controllable strategy to facilitate charge separation in photocatalysis. The homophase junctions exhibit atomiclevel contact for the fast-speed charge transfer via inducing the built-in electric fields. Herein, a new concept of TiO 2 quasi-core−shell homophase junction induced by a Ti 3+ concentration difference for remarkably enhancing photocatalytic activity is proposed. Nano anatase TiO 2 quasi-core−shell homophase junctions are constructed between the interior with high Ti 3+ concentration (quasi-core) and the surface with no detected Ti 3+ (quasi-shell). Diverse Ti 3+ concentration differences are obtained via regulating the mass ratio of the Ti source. The nano anatase TiO 2 quasi-core−shell homophase junctions exhibit improved photocatalytic hydrogen evolution compared with commercial anatase nanoparticles. To be specific, the maximum hydrogen evolution rate of 50.02 mmol/h/g is 25.4 times superior to that of commercial anatase nanoparticles under solar illumination. Besides, the photocatalytic activity remains stable (H 2 evolution rate of 49.21 mmol/h/g, activity loss of <2%) after five cycles of catalytic test. The promoted photocatalytic activities are ascribed to the constitution of a built-in electrical field between the quasishell and quasi-core induced by the band bending, which accelerates the spatial charge separation and suppresses the recombination of carriers. Moreover, the atomic-level contact at the homophase junction interface provides smooth channels for carrier transfer, resulting in more effective separation and transfer of photogenerated electrons and holes. The synthesis of nano anatase TiO 2 quasicore−shell homophase junctions provides new insights into the efficient separation and transfer of photogenerated carriers for photocatalytic applications.
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