Let your light shine: the photocatalytic reduction of carbon dioxide to the formate anion under visible light irradiation is for the first time realized over a photoactive Ti-containing metal-organic framework, NH(2)-MIL-125(Ti), which is fabricated by a facile substitution of ligands in the UV-responsive MIL-125(Ti) material.

Metal-organic frameworks (MOFs) have shown great promise for CO2 capture and storage. However, the operation of chemical redox functions of framework substances and organic CO2 -trapping entities which are spatially linked together to catalyze CO2 conversion has had much less attention. Reported herein is a cobalt-containing zeolitic imidazolate framework (Co-ZIF-9) which serves as a robust MOF cocatalyst to reduce CO2 by cooperating with a ruthenium-based photosensitizer. The catalytic turnover number of Co-ZIF-9 was about 450 within 2.5 hours under mild reaction conditions, while still keeping its original reactivity during prolonged operation.

Semiconducting carbon nitride materials were successfully prepared via a thermal poly-condensation of dicyandiamide as a precursor at >500 1C. The resulting materials were investigated as metal-free catalysts for the activation of H 2 O 2 with visible light under mild conditions, using the decomposition of Rhodamine B (RhB) in aqueous solution as a model reaction. Results revealed that carbon nitride catalysts can activate H 2 O 2 to generate reactive oxy-radicals under visible light irradiation without employment of any metal additives, leading to the mineralization of the dye. Factors affecting the degradation of organic compounds are pH values and the concentration of H 2 O 2 . Recycling of the catalyst indicated no obvious deactivation during the entire catalytic reaction, indicating good (photo)chemical stability of metal-free polymeric carbon nitride photocatalysts for environmental purification. This study demonstrated a promising approach for the activation of green oxidant, hydrogen peroxide, by the newly-developed polymer photocatalysts for environmental remediation and oxidation catalysis.

Hot: Conjugated carbon nitride polymers (LCNs) are synthesized by hot‐fluid annealing in one pot. The LCNs possess a narrow band gap, have a complex nanostructure, and show enhanced photochemical performances. The described synthesis approach will allow the rational creation of a wide variety of polymeric carbon nitride semiconductors at low temperature in solutions, with control of structural complexity, electronic structure, and surface functionality.

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An amine-functionalized zirconium metal-organic framework (MOF) was used as a visible-light photocatalyst for selective aerobic oxygenation of various organic compounds including alcohols, olefins and cyclic alkanes, at high efficiency and high selectivity. This study shows the great potential for design and application of MOF-based photocatalysts.

Modification of graphitic carbon nitride (g-C(3)N(4)) photocatalyst with transition metals was achieved with a simple soft-chemical approach using dicyandiamide monomer and metal chloride as precursors, in combination with a thermal-induced polycondensation at 600 °C under nitrogen atmosphere. The resultant organic-inorganic hybrid materials were thoroughly characterized by a variety of techniques, including X-ray diffraction (XRD), UV/Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), N(2)-sorption, transmission electron microscopy (TEM), photoluminescence (PL), and FTIR. Benzene hydroxylation and styrene epoxidation reactions were employed to evaluate the catalytic/photocatalytic activity of the synthesized g-C(3)N(4)-based catalysts. Results showed that Fe- and Cu-modified g-C(3)N(4) were active for the hydroxylation of benzene to phenol using H(2)O(2) under mild conditions. It was also found that g-C(3)N(4) could promote the catalytic epoxidation of styrene using molecular oxygen as the primary oxidant; after modification with Co and Fe, the catalytic performance for styrene epoxidation with O(2) could be significantly improved, especially when coupled with visible-light irradiation.

The capture and efficient use of CO 2 is an important issue because CO 2 released by burning fossil fuels is a primary cause of global warming. One of the best solutions is to convert CO 2 into valuable organic products by means of solar energy. Thus many research efforts have been made to develop efficient heterogeneous photocatalysts for the reduction of CO 2 . The examined photocatalysts range from semiconducting materials, such as TiO 2 , CdS, ZnGa 2 O 4 , and Zn 2 GeO 4 , to metal-incorporated zeolites including Ti-bzeolite, Ti-MCM-41, Ti-MCM-48, and ZrCu(I)-MCM-41. [1,2] The fact that the Ti-immobilized zeolites show even much higher efficiency for the reduction of CO 2 over TiO 2 indicates that the incorporation of Ti into porous materials will be a promising strategy, although almost all currently developed photocatalysts are only active in the region of UV light and their efficiency for the reduction of CO 2 is still quite low.Metal-organic frameworks (MOFs) are a class of crystalline micro-mesoporous hybrid materials with an extended 3D network which have shown a variety of potential applications. [3][4][5][6][7][8][9] Especially, MOFs are used for the development of heterogeneous catalysts. In fact, a variety of heterogeneous MOF catalysts has been realized over the past decade by introducing different types of catalytic sites into a porous MOF matrix. [9] Photocatalysis is a unique kind of heterogeneous catalysis which involves the use of a light source. Theoretically, it is also feasible to develop MOF photocatalysts by immobilizing photoactive catalytic sites in MOF materials. The effective use of solar light can be facilely achieved by modifications on the metal ions or the organic ligands in the MOFs. [10] Although theoretically established, a successful tuning of the absorption of the MOFs for their application in visible light photocatalysis has not yet been realized experimentally. Besides this matter, only a couple of MOFs have been reported to show photocatalytic activities for dye degradation and water splitting. [11] Motivated by the above-mentioned discoveries on the Ti-incorporated zeolite photocatalysts, we initiated a research program to develop photoactive MOF photocatalysts for the reduction of CO 2 after a Ti-based MOF Ti 8 O 8 (OH) 4 (bdc) 6 (MIL-125(Ti)) had been reported (BDC = benzene-1,4-dicarboxylate). [12] This type of MOF material cannot only introduce high density of the immobilized Ti sites within porous MOFs, but it can also lead to isostructural MOFs, the photocatalytic properties of which can simply be tuned by incorporation of BDC derivatives. Indeed, the introduction of NH 2 groups in BDC in the MIL-125(Ti) material to prepare isostructural NH 2 -MIL-125(Ti) for H 2 adsorption was recently reported by Zlotea et al. [13] Herein we report for the first time a targeted photoactive catalyst Ti 8 O 8 (OH) 4 (bdc-NH 2 ) 6 (NH 2 -MIL-125(Ti)), which reduces CO 2 even under visible light irradiation (BDC-NH 2 = 2-amino-benzene-1,4-dicarboxylate; ATA = 2-aminoterephthalate).NH ...