Photocatalytic degradation of aqueous Methyl Orange using nitrogen-doped TiO_2 photocatalyst prepared by novel method of ultraviolet-assisted thermal synthesis

A nitrogen-doped titanium dioxide composite photocatalyst（N–TiO2） with heterojunction structures is synthesized by three different approaches： a novel UV-assisted thermal synthesis, annealing, and microwave technique. Photocatalytic activities of synthesized photocatalysts are evaluated by the degradation of Methyl Orange under ultraviolet light types A（UV-A）, B（UV-B）, and C（UV-C）, visible light, and direct sunlight irradiation. Results show that by using N–TiO_2 photocatalyst prepared by the UV-assisted thermal synthesis and annealing, the degradation increases by 16.5% and 20.4%, respectively, compared to that by bare TiO2. The best results are obtained at a nitrogen to TiO2 mass ratio of 0.15（N：TiO2）. The enhancement of the photocatalytic activity observed in the visible range is mainly attributed to the increasing separation rate of photogenerated charge carriers. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method for the nitrogen-doped TiO2 photocatalyst; thus, further studies are recommended for process optimization, immobilization, and scale-up to evaluate its applicability in wastewater treatment.

Flexible Broadband Light Absorbers with a Superhydrophobic Surface Fabricated by Ultraviolet-assisted Nanoimprint Lithography

We present a simple approach to fabricate a kind of composite films with a superhydrophobic and broadband light absorbing surface by ultraviolet-assisted nanoimprinting over a gradiently deposited composite matrix.The wettability and optical property of the resultant surfaces are tunable by the deposition time before polymerization(T_(s))and mold’s topography.Mechanically robust and elastomeric films exhibiting high sunlight absorptivity up to 98.13%and contact angle of their surfaces up to 150°are prepared under optimized conditions,as using a mold with a small pattern size(hexagonal periodic mold with cylinder diameter of ca.37μm)under T_(s)=10 min for imprinting the crosslinked poly[di(ethylene glycol)ethyl ether acrylate]and poly(isobornyl acrylate)in the presence of polypyrrole(PPy)nanoparticles.Such dual functions are found related to the hierarchical architecture of the surface,arising from the synergetic effects of the periodical patterned polymer substrate and spontaneously assembled PPy microstructures on the patterns.The current strategy based on the combination of ultraviolet-assisted nanoimprint lithography and hierarchical assembly of gradiently deposited black nano-fillers offers a new insight into the design of robust superhydrophobic and black surfaces,which is helpful to deepen our understanding of the relationship between liquid/light manipulation and micro/nanostructured surfaces.