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Abstract Photocatalytic water purification has emerged as new effective ways for an environment preserve and purification in few decades. As a part of studies on photocatalytic water purification, constructing heterojunction structured compounds with different photocatalysts for efficient organic pollutant degradation is regarded as key-strategy. Herein, facile one-step carbonizing process was introduced for synthesizing Fe 2 O 3 /C-g-C 3 N 4 based Z-scheme heterojunction photocatalyst. The two times of photocatalytic organic pollutant degradation rate of Fe 2 O 3 /C-g-C 3 N 4 based Z-scheme heterojunction photocatalyst was enhanced comparing with pristine Fe 2 O 3 /g-C 3 N 4 heterojunction photocatalyst through rhodamine B (RhB) degradation under AM 1.5G (100 mWcm−2, 1 sun) illumination. The reasons for enhanced photocatalytic RhB degradation efficiency of Fe 2 O 3 /C-g-C 3 N 4 based Z-scheme heterojunction photocatalyst were revealed to efficient charge transfer during light induced RhB degradation reaction by constructing junction structures among Fe 2 O 3 , amorphous carbon layer and g-C 3 N 4 , which proved by fluorescence spectroscopy, XPS, SEM, TEM and UV–Vis analysis. Graphical abstract Image 1 Highlights • Fe 2 O 3 /g-C- 3 N 4 (Fg) and Fe 2 O 3 /C-g-C 3 N 4 (FCg) heterojunction photocatalysts synthesized via simple solid-state reaction. • Z-scheme heterojunction between Fe 2 O 3 and g-C 3 N 4 was constructed by insertion of amorphous carbon layer. • Photocatalytic activities of double charge transfer or Z-scheme heterojunction between Fe 2 O 3 and g-C 3 N 4 was studied. [ABSTRACT FROM AUTHOR]

A (040)-crystal facet engineered BiVO4 ((040)-BVO) photoanode is investigated for solar fuel production. The (040)-BVO photoanode is favorable for improved charge carrier mobility and high photocatalytic active sites for solar light energy conversion. This crystal facet design of the (040)-BVO photoanode leads to an increase in the energy conversion efficiency for solar fuel production and an enhancement of the oxygen evolution rate. The photocurrent density of the (040)-BVO photoanode is determined to be 0.94 mA cm−2 under AM 1.5 G illumination and produces 42.1% of the absorbed photon-to-current conversion efficiency at 1.23 V (vs RHE, reversible hydrogen electrode). The enhanced charge separation efficiency and improved charge injection efficiency driven by (040) facet can produce hydrogen with 0.02 mmol h−1 at 1.23 V. The correlation between the (040)-BVO photoanode and the solar fuel production is investigated. The results provide a promising approach for the development of solar fuel production using a BiVO4 photoanode. [ABSTRACT FROM AUTHOR]

The photocatalysis, chromism, and sensing capabilities of nanostructured tungsten oxides, such as tungsten trioxide (WO3), its suboxides (WOx, 0 ＜ x ＜ 3) and hydrates (WO3·nH2O, n = 1/3 (0.33), 0.5, 0.75, 1, 2, etc.), tungsten bronzes MxWO3 (M = Li, Na, K, Rb, Cs and NH4), and metal tungstates (such as Bi2WO6 and CuWO4) have attracted much attention. To improve these properties, many strategies have been pursued, such as morphology control, doping, and heterostructuring. Crystal facet engineering has recently become a very important method of fine-tuning the physicochemical properties of semiconductors. The photocatalytic reactivity of a photocatalyst is significantly affected by its surface environment, including its surface electronic and atomic structures, which strongly depend on the crystal facets. It is believed that crystals with different exposed facets will have different properties, with the exposure of highly activated facets enhancing the photocatalytic and sensing properties. This article describes the syntheses of 2D WO3 crystals with the {002} facet primarily exposed, octahedral WO3 or WO3·nH2O with exposed {111} facets, and WO3 films with dominant orientations, such as orientation along the {002} facet. WO3 doping, WO3-based heterostructuring and their applications are also presented in this paper. [ABSTRACT FROM AUTHOR]