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A novel, economical and magnetically separable heterojunction photocatalyst Fe3O4/BiOBr stacked on reed straw biochar (Fe3O4/BiOBr/BC) with visible light response was successfully prepared via a facile modified one-step hydrolysis method for the first time. The target pollutant carbamazepine (CBZ) was used to further investigate the photocatalytic activity of Fe3O4/BiOBr/BC. Compared with BiOBr and Fe3O4/BiOBr, novel photocatalyst Fe3O4/BiOBr/BC owing to the introduction of biochar exhibited better photocatalytic activity (95.51%) of CBZ photodegradation even under 50 W energy-saving visible LED light irradiation. Additionally, effect of pH on CBZ photodegradation using Fe3O4/BiOBr/BC was insignificant meaning wider practical application. Besides, three common anions (Cl−, NO3−, SO42−) and DOM existing in natural water exhibited beneficial or detrimental effects to some extent. Free radicals trapping experiments results illustrated high carbamazepine removal efficiency could be ascribed to superoxide radicals and hydroxyl radicals. The transformation intermediates of CBZ were determined by HRMS and the possible photodegradation pathways were proposed. Finally, good reusability and stability verified the excellent practicality and feasibility of Fe3O4/BiOBr/BC for removal of organic pollutants in aqueous.

Fe-based metal-organic frameworks (MOFs) have shown promising applications in photocatalysis, yet they are incapable of photocatalytic H2 production due to their inappropriate conduction band (CB) position and large overpotential for H2 evolution. Herein, we present a facile strategy enabling the photocatalytic H2 production over Fe-based MOFs through dye sensitization. A combination of characterization techniques with theoretical simulation reveals that dye sensitization can effectively inject energetic electrons into Fe-MOFs and elevate their quasi-Fermi level under light irradiation, overcoming the surface overpotential for H2 production from water. Furthermore, deposition of Pt nanoparticles on Fe-MOFs can lower the overpotential for H2 evolution toward further enhanced photocatalytic activity. This work provides insights into MOF band structure engineering at electronic level, and proves a concept that harnesses MOF materials for targeted photocatalytic applications they are originally not fit for.

Coexistence of organic compounds and heavy metals in aquaculture waters is a widespread problem. In this study, a rapid reduction of Cr(VI) and oxidation of ciprofloxacin (CIP) in a simultaneous manner was firstly reported through the photocatalysis of TiO 2 /Fe 0 composite under aerobic conditions. The significantly enhanced removals of Cr(VI) and CIP by TiO 2 /Fe 0 composite due to a synergetic effect between oxidation and reduction processes. Within 60 min UV light irradiation, the simultaneous removals of Cr(VI) and CIP by TiO 2 /Fe 0 composite were 97.7 and 94.6%, respectively, whereas the corresponding values by TiO 2 were 57.9 and 68.7%. CIP oxidation process could be significantly accelerated under acidic and aerobic conditions. Intriguingly, a low Pb(II) concentration could induce an enhancement of CIP oxidation, whereas a negative effect on both Cr(VI) reduction and CIP oxidation was observed at a relatively high concentration. A low concentration of ethylene diamine tetra-acetic acid (EDTA) did positively affect both Cr(VI) reduction and CIP oxidation processes, whereas a negative effect on CIP oxidation was found at a relatively high concentration. A possible reaction pathway and mechanism between CIP oxidation and Cr(VI) reduction was proposed. CIP was attacked by HO produced from the decomposition of water and photo-excited holes through substitution and hydroxylation processes, leading to the production of a series of intermediates, whereas the Cr(VI) was converted into Cr(III) through the capture of photo-excited electrons and Fe 0 reduction.

Materials with reversible optical properties under light irradiation have great potential application in various optoelectronic fields. Particularly, photochromic materials have received extensive attention in many fields. Herein, a novel composite photochromic fabric was fabricated via Layer-by-Layer self-assembling of phosphomolybdic acid (PMoA) and polyacrylamide (PAM). Based on the established electron transfer photochromic system, the dynamic manipulation of photochromic behavior of the cotton fabric was achieved with outstanding fine high-resolution image under the visible light irradiation. The prepared fabric can change from colorless to blue rapidly (within 5 min) under UV light and maintain excellent reusability photochromic performance after more than 20 reversible color changing cycles, implying its great potential applications in the field of intelligent devices and UV detection in sunlight. Moreover, we constructed fabric weaving and developed a Quick Response (QR) code security identification to prove the practical application of the prepared photochromic fabric in the fields of wearable, optical information storage and information security encryption.

Series of BiOIO 3 photocatalysts prepared at different pH values via a facile hydrothermal method were used to remove gaseous elemental mercury under UV and LED light irradiation. Results showed that the morphology and crystal structure of BiOIO 3 products could be controlled by the pH value of precursor. The BiOIO 3 products could be obtained only at strong acid condition. The BiOIO 3 sample with nanosheets morphology prepared at 2.03 ⩽ pH ⩽ 3.05 exhibited superior photocatalytic activity and nearly 100% of Hg 0 were removed after UV light (25 min) and LED light (100 min) irradiation. The removal efficiency of Hg 0 was higher than that of P25 (UV light, 77%, LED light, 42%) under the same condition. The photogenerated holes were the main oxidative species responsible for the oxidation removal of Hg 0 . This newly BiOIO 3 photocatalysts, with superior photocatalytic activity and good stability have potential application for the Hg 0 oxidation removal.

Tungsten, silver and tungsten/silver co-doped titania nanopowders were synthesised via an aqueous sol-gel method. The size distribution and zeta potential of the starting sols were determined via photon correlation spectroscopy (PCS). The dried gels were thermally treated at two different temperatures, and the occurrence of amorphous phase was assessed using the combined Rietveld-RIR X-ray powder diffraction method. A systematic study of the optical properties of the powders was made with diffuse reflectance spectroscopy (DRS), and the energy band gaps were calculated using the differential reflectance method; while their morphology was investigated using electron microscopy analysis (TEM). The photocatalytic activity of the samples was assessed in liquid-solid phase, under UVA-light and visible-light irradiation, monitoring the degradation of an organic dye. The influence of the phase composition, optical properties, dimensions, and specific surface area of the powders on the photocatalytic activity was thoroughly discussed. (C) 2012 Elsevier B.V. All rights reserved.