Designing and fabricating a CdS QDs/Bi2MoO6 monolayer S-scheme heterojunction for highly efficient photocatalytic C2H4 degradation under visible light.

Achieving efficient photocatalytic degradation of atmospheric volatile organic compounds (VOCs) under sun-light is still a significant challenge for environmental protection. The S-scheme heterojunction with its unique charge migration route, high charge separation rate and strong redox ability, has great potential. However, how to regulate interfacial charge transfer of the S-scheme heterojunction is of significant importance. Here, density functional theory (DFT) calculations were first conducted and predicted that an S-scheme heterojunction could be formed in the CdS quantum dots/Bi2MoO6 monolayer system. Subsequently, this novel heterojunction is constructed by in-situ hydrothermal synthesis of CdS quantum dots on monolayer Bi2MoO6. Under visible-light, this novel S-scheme system gives a high-efficiency photocatalytic degradation rate (6.04 × 10-2 min-1) towards C2H4, which is 30.3 times higher than that of pure CdS (1.99 × 10-3 min-1) and 41.7 times higher than pure Bi2MoO6 (1.45 × 10-3 min-1). Strong evidence for the S-scheme charge transfer path is provided by in-situ XPS, PL, TRPL and EPR.

Design and synthesis of 2-(4,5,6,7-tetrahydrothienopyridin-2-yl)-benzoimidazole carboxamides as novel orally efficacious Poly(ADP-ribose)polymerase (PARP) inhibitors.

The nuclear protein poly(ADP-ribose) polymerases-1/2 (PARP-1/2) are involved in DNA repair damaged by endogenous or exogenous process. And PARP-1/2 inhibitors have been proved to be clinically efficacious for DNA repair deficient tumors in the past decade. We have developed a series of 4,5,6,7-tetrahydrothienopyridin-2-yl benzimidazole carboxamides as novel and potent PARP-1/2 inhibitors. The best compound resulted from this series is compound 27 which displays excellent PARP-1 and PARP-2 inhibitory activity with IC50 of 18 nM and 42 nM, respectively. Furthermore, it can selectively kill BRCA2 deficient V-C8 cells with a CC50 of 920 nM. In the MDA-MB-436 (BRCA-1 mutant) xenograft model, this compound was well tolerated and showed single-agent activity. Based on the results above, compound 27 has been selected as a lead candidate targeting PARP-1/2 and its preclinical characterization is also underway.

Photocatalytic oxidation of methane over SrCO3 decorated SrTiO3 nanocatalysts via a synergistic effect.

Because of the high C-H bond energy as well as the non-polar feature of CH4 molecules, oxidation of methane under mild conditions remains a challenging task for both C1 utilization and atmospheric environmental cleansing. Here we report that by using a sol-gel method SrCO3 decorated SrTiO3 nanocatalysts (SrTiO3-S) with an average particle size of ∼25 nm can be readily prepared, which surprisingly show efficient performance for photocatalytic oxidation of methane with the activity close to fourfold of P25, a benchmark photocatalyst. Further investigation revealed a synergistic effect between SrCO3 and SrTiO3 when combined together into a composite material as both of which are totally inactive for methane oxidation if used alone. Gas adsorption characterization disclosed that the SrCO3 can adsorb methane and cannot adsorb carbon dioxide, whereas the SrTiO3 will preferentially adsorb CO2 instead of CH4. Photocurrent and photoluminescence measurements indicate that SrCO3 exhibits a negligible photocurrent response relative to the SrTiO3 semiconductor under simulated solar light illumination but the formation of the SrCO3/SrTiO3 junction structure (SrTiO3-S) helps reduce surface recombination of the photogenerated electrons and holes. All these results refer to the synergistic mechanism in which the SrCO3 acts as a trapping agent to adsorb methane and weaken its C-H bond while the SrTiO3 acts as a photocatalyst to activate and oxidize methane under light illumination. The underlying photooxidation mechanism is further investigated with the aid of in situ electron paramagnetic resonance and infrared spectroscopy.

Photocatalytic oxidation of methane over silver decorated zinc oxide nanocatalysts.

The search for active catalysts that efficiently oxidize methane under ambient conditions remains a challenging task for both C1 utilization and atmospheric cleansing. Here, we show that when the particle size of zinc oxide is reduced down to the nanoscale, it exhibits high activity for methane oxidation under simulated sunlight illumination, and nano silver decoration further enhances the photo-activity via the surface plasmon resonance. The high quantum yield of 8% at wavelengths <400 nm and over 0.1% at wavelengths ∼470 nm achieved on the silver decorated zinc oxide nanostructures shows great promise for atmospheric methane oxidation. Moreover, the nano-particulate composites can efficiently photo-oxidize other small molecular hydrocarbons such as ethane, propane and ethylene, and in particular, can dehydrogenize methane to generate ethane, ethylene and so on. On the basis of the experimental results, a two-step photocatalytic reaction process is suggested to account for the methane photo-oxidation.

Defective, Porous TiO2 Nanosheets with Pt Decoration as an Efficient Photocatalyst for Ethylene Oxidation Synthesized by a C3N4 Templating Method.

We report herein a C3N4 templating method for successfully synthesizing defective, porous TiO2 nanosheets with Pt decoration as an efficient photocatalyst for C2H4 oxidation. During the synthetic procedure, C3N4 not only acts as a 2D template to direct synthesize porous TiO2 nanosheets (TiO2-NS) but also facilitates oxygen vacancy formation on TiO2. The resultant TiO2-NS shows enhanced UV and visible-light photoactivities toward C2H4 oxidation as compared to blank TiO2 (TiO2-B) prepared without C3N4 template. Subsquently, Pt nanoparticles are homogeneously decorated onto the surface of TiO2-NS. The as-obtained Pt-TiO2-NS exhibits efficient photocatalytic activity and stability toward ethylene oxidation.

Enhanced ethylene photodegradation performance of g-C3N4-Ag3PO4 composites with direct Z-scheme configuration.

Photocatalytic oxidation of ethylene continues to be a challenge at the frontier of chemistry. In a previous report, a simple Ag3 PO4 semiconductor material was shown to have strong photooxidative properties and efficiently oxidised water and decomposed organics in aqueous solution under visible-light illumination. Herein, its effects on the photo-oxidation of gaseous C2 H4 were investigated by fabricating graphitic C3 N4-Ag3 PO4 composite semiconductors with direct Z-scheme configuration. It was found that both the ethylene photo-oxidative activity and the stability of Ag3 PO4 are considerably improved by fabrication of Z-scheme composites. Moreover, stable C2 H4 photo-oxidation activity could be obtained by treating the composite at 450 °C for 3 h after long-term operation. From the point of view of environmental pollutant cleanup, the present technique avoids the side reaction of oxidising water and will be valuable for further investigations on both Ag3 PO4 and CH degradation.

Bimetallic alloy nanocrystals encapsulated in ZIF-8 for synergistic catalysis of ethylene oxidative degradation.

Highly dispersed PtPd alloy nanocrystals (NCs) were firstly successfully encapsulated in microporous zeolitic imidazolate framework ZIF-8 (PtPd@ZIF-8) with tunable compositions by a "bottle around ship" approach. The PtPd@ZIF-8 catalyst showed excellent synergistic photocatalytic activity in the transformation of the adsorbed ethylene into CO2 and H2O at room temperature.

Palladium-catalyzed oxidative C-H/C-H cross-coupling of benzothiazoles with thiophenes and thiazoles.

A concise palladium-catalyzed method for oxidative C-H/C-H cross-coupling between benzothiazoles and thiophenes/thiazoles has been developed. This CDC reaction is insensitive to air and moisture with high functional group tolerance.

Palladium(II)-catalyzed synthesis of functionalized indenones via oxidation and cyclization of 2-(2-arylethynylphenyl)acetonitriles.

A one-pot two-step synthesis of versatile indenones has been developed. This palladium(II)-catalyzed transformation involves generation and condensation of ortho-functionalized 1,2-benzils from 2-(2-arylethynylphenyl)acetonitriles using Ph2SO as the oxidant. The resulting 3-cyanoindenones can be converted to various valuable molecules.

Synthesis of novel functional polycyclic chromones through Michael addition and double cyclizations.

A base-promoted, microwave-assisted one-pot tandem reaction from simple 3-(1-alkynyl)chromones with 2-halobenzylic nitriles (esters or amides) for the synthesis of novel functional polycyclic chromenones has been developed. This tandem process involves multiple reactions, such as Michael addition and double cyclizations without a transition metal catalyst.

Simultaneous dispersion and dispersion-slope compensator based on a doubly sampled ultrahigh-channel-count fiber Bragg grating.

A simultaneous dispersion and dispersion-slope compensator based on a doubly sampled fiber Bragg grating (FBG) with 153 channels has been demonstrated, which is obtained by simultaneously chirping the period of the seed grating and the periods of the two sampling functions. These two sampling functions are optimized with the simulated annealing algorithm and the Gerchberg-Saxton iterative method. Moreover, the spectral inclination (in reflection) inherently due to the different magnitudes of the channel dispersion has been successfully equalized.

Multiwavelength fiber laser based on the utilization of a phase-shifted phase-only sampled fiber Bragg grating.

A semiconductor-optical-amplifier-based fiber laser incorporating with a phase-shifted phase-only sampled fiber Bragg grating (FBG) is proposed and experimentally demonstrated. Thanks to the intrinsic property of the phase-shifted phase-only sampled FBG, the proposed approach has an unique advantage, enabling one to tune and switch all the wavelength lasing simultaneously. The obtained fiber laser has a stable output with more than 30 wavelengths lasing. The 3 dB linewidth is approximately 13 pm, the signal-to-noise ratio is larger than 50 dB, and the nonuniformity of the output is smaller than 7.4 dB.

Advanced design of the ultrahigh-channel-count fiber Bragg grating based on the double sampling method.

A double sampling method enabling to have excellent channel uniformity and high in-band energy efficiency is firstly proposed for the design of an ultrahigh-channel-count fiber Bragg grating (FBG), which is based on the simultaneously utilization of an amplitude-assisted phase sampling (AAPS) function and a phase-only sampling (POS) function. As examples, two typical 10-dB FBGs with a length of 12 cm, dispersion of - 1360 ps/nm, channel spacing of 0.8 nm, and a consecutive 135- and 405- channels are numerically designed. The maximum index-modulations required are about 0.8x10(-3), and 1.3x10(-3), respectively. Compared with the proposed method, the other two kinds of double sampling schemes by utilizing either the double AAPS (i.e., AAPS+AAPS) or the double POS (i.e., POS+POS) have also been introduced for the design of the multichannel FBGs. Fabrication tolerances to the designed 135-channel FBG obtained with the AAPS plus POS method are numerically investigated.