BiOCl nanosheets (BiOCl NSs) were synthesized by hydrolyzing a hierarchical flowerlike molecular precursor (Bi(n)(Tu)(x)Cl(3n), Tu = thiourea). High photoactivity of {001} facets of BiOCl NSs was observed, and the mechanism was discussed.

Ag/AgX/BiOX (X = Cl, Br) three-component visible-light-driven (VLD) photocatalysts were synthesized by a low-temperature chemical bath method and characterized by X-ray diffraction patterns, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and UV−vis diffuse reflectance spectra. The Ag/ AgX/BiOX composites showed enhanced VLD photocatalytic activity for the degradation of rhodamine B, which was much higher than Ag/AgX and BiOX. The photocatalytic mechanisms were analyzed by active species trapping and superoxide radical quantification experiments. It revealed that metallic Ag played a different role for Ag/AgX/BiOX VLD photocatalysts, surface plasmon resonance for Ag/AgCl/BiOCl, and the Z-scheme bridge for Ag/AgBr/BiOBr.

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Porous graphitic carbon nitride (g-C(3)N(4)) was prepared by a simple pyrolysis of urea, and then a g-C(3)N(4)-Pt-TiO(2) nanocomposite was fabricated via a facile chemical adsorption followed by a calcination process. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance absorption spectra, and electron microscopy. It is found that the visible-light-induced photocatalytic hydrogen evolution rate can be remarkably enhanced by coupling TiO(2) with the above g-C(3)N(4), and the g-C(3)N(4)-Pt-TiO(2) composite with a mass ratio of 70 : 30 has the maximum photoactivity and excellent photostability for hydrogen production under visible-light irradiation, and the stable photocurrent of g-C(3)N(4)-TiO(2) is about 1.5 times higher than that of the bare g-C(3)N(4). The above experimental results show that the photogenerated electrons of g-C(3)N(4) can directionally migrate to Pt-TiO(2) due to the close interfacial connections and the synergistic effect existing between Pt-TiO(2) and g-C(3)N(4) where photogenerated electrons and holes are efficiently separated in space, which is beneficial for retarding the charge recombination and improving the photoactivity.

Two kinds of graphitic carbon nitride (g-C 3 N 4 ) were synthesized through a pyrolysis process of urea or melamine. It is found that the obtained g-C 3 N 4 , as photocatalysts, can reduce CO 2 to organic fuels under visible light, and exhibit different photoactivity and selectivity on the formation of CH 3 OH and C 2 H 5 OH. The product derived from the urea (denoted as u-g-C 3 N 4 ) shows a mesoporous flake-like structure with a larger surface area and higher photoactivity for the CO 2 reduction than the non-porous flaky product obtained from melamine (denoted as m-g-C 3 N 4 ). Moreover, using u-g-C 3 N 4 as a photocatalyst can result in the formation of a mixture containing CH 3 OH and C 2 H 5 OH, while m-g-C 3 N 4 only leads to the selective formation of C 2 H 5 OH. The present interesting findings could shed light on the design of efficient, eco-friendly and convenient photocatalysts and the tuning of their photoreactivity in the field of sustainable light-to-energy conversion.

Black BiOCl with oxygen vacancies was prepared by UV light irradiation with Ar blowing. The as-prepared black BiOCl sample showed 20 times higher visible light photocatalytic activity than white BiOCl for RhB degradation. The trapping experiment showed that the superoxide radical (O(2)(•-)) and holes (h(+)) were the main active species in aqueous solution under visible light irradiation.

Highly symmetrical BiOI single-crystal nanosheets (BiOI SCNs) with dominant exposed {001} facets (up to 95%) have been synthesized by annealing BiI 3 and characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, high-resolution transmission electron microscopy, fast-Fourier transform pattern, UV-vis diffuse reflectance and photoluminescence. The thickness and the {001} facets percentage of BiOI SCNs can be tuned by changing the annealing temperature. The thermal decomposition process of BiI 3 and the formation mechanism of BiOI SCNs were investigated. BiOI SCNs exhibit higher photoactivity (about 7 times) than irregular BiOI for degradation of Rhodamine B (RhB) dye under visible light irradiation. The {001} facets are the reactive facets of BiOI. The origin of {001} facets-dependent photoactivity is due to an improvement of the separation efficiency of photo-induced electrons and holes.