Photodecomposition of H_2S to H_2 over Cd_xZn_(1-x)S composite photocatalysts

A series of CdxZn1-xS (x = 0.1-0.9) photocatalysts were prepared by coprecipitation. They could form solid solution semiconductors with hexagonal phase in agreement with pure CdS by characterization of XRD. The photophysical properties of CdxZn1-xS photocatalysts were measured by UV-Vis diffuse reflectance spectrum and surface photovoltage spectroscopy (SPS). The band gap energy gradually reduced with the increasing of x value in CdxZn1-xS,and when x = 0.7,the Cd0.7Zn0.3S photocatalyst had the strongest surface photovoltage. CdxZn1-xS photocatalysts were used in the photodecomposition of H2S to H2. The evolution rate of H2 over the Cd0.7Zn0.3S photocatalyst was also the highest among CdxZn1-xS photocatalysts. And the effect of calcination temperature on the evolution rate of H2 was investigated and the optimum temperature was 650°C.

Yeast-TiO₂Biotemplate for Oxytetracycline Solar Photodecomposition

The detection of the pharmaceutical compounds used in human and veterinary medicine is in several environmental matrices (surface waters, effluents, groundwater, soils, and sediments), and such presence promotes the resistance bacteria development, making them ineffective in some diseases treatment. The research project promotes the TiO2 synthesis using yeast culture as biotemplate, the step followed by the microstructure characterization with surface area enhancement;such properties are responsible for the improvement of solar photodecomposition processes of the veterinary antibiotic oxytetracycline. In such simple and standard process conditions the system reaches about 84% of removal percentage with a better agreement with the pseudo-first-order with the Pearson coefficient in the range from 0.82 to 0.94 and K1 = 0.035 M−1∙s−1. The degradation rate constant increased with the increasing initial Yeast-TiO2 dosage until the maximum mass of 0.1 g or with the decreasing of initial oxytetracycline concentration. The solar light used as a sustainable irradiation source is abundant and low cost in tropical countries, perfect to be applied in water treatment to decompose the pharmaceuticals pollutants, as the veterinarian antibiotics. The study demonstrates that solar photodecomposition is an efficient treatment technology for the removal of antibiotics from polluted water and provides insightful information on the potential practical application of this technology to treat contaminated water, possibly also in rural, distant areas.

Oxytetracycline Water Contamination Treated with Biocarbon TiO2 and Solar Photodecomposition

Reliable data of antibiotic use and environmental discharge as veterinary medicine are essential to help countries raise awareness of the appropriate use, control, and correct water release. The first approach is to change the regulatory framework based on consuming information, use policy, and discharge laws. The important research contribution is a novel water treatment process to treat, remove, and reduce antibiotic concentration in discharged water, mainly those used in the animal protein industry. The low particle biochar added during the titanium isopropoxide hydrolysis reduces the titanium dioxide (TiO2) agglomerates and promotes the adsorption surface process. Such improved catalyst material enhances the solar decomposition efficiency to 93% from original oxytetracycline with better correspondence with the Elovich kinetics, intraparticle diffusion, R-P isotherm, and Langmuir-Hinshelwood model.

Plasmon-mediated photodecomposition of NH3 via intramolecular charge transfer

As an excellent clean medium for hydrogen storage and fuel cell applications,the photolysis of ammonia via localized surface plasmon could be invoked as a promising route towards significantly reducing the temperature for conventional thermolysis.Here,we explore the underlying microscopic mechanism of ultrafast carrier dynamics in plasmon-mediated NH3 photodecomposition at the single-molecular level using real-time time-dependent density functional theory.The NH_(3)molecule adsorbed on the tip of archetypal magic metal clusters represented by tetrahedral Ag_(2)0 and icosahedral Ag147,splits within a hundred femtoseconds upon laser pulse illumination.We found that the splitting of the first N-H bond is dominated by the intramolecular charge transfer driven by localized surface plasmon.Surprisingly,the phase of laser pulse could modulate the dynamics of charge transfer and thus affect the plasmon-induced bond breaking.These findings offer a new avenue for NH3 decomposition and provide in-depth insights in designing highly efficient plasmon-mediated photocatalysts.

Absorption and Emission Spectra of p-Phenylbenzoyl Methanthiol: Methanol Effect Based on M06-2X Calculations

The absorption and emission spectra, as well as the photolysis mechanism of p-phenylbenzoyl methanthiol in methanol and in gas phase were elucidated in detail based on the molecular structures of the ground states, excited states and their spectroscopic characters. The TD-M062 X calculations demonstrate that the S_1 state in gas phase will decompose into SH and p-phenylbenzoyl radical via a barrierless process, but the T_1 and T_2 do not photolyze. By adding 1 and 2 methanol molecules onto p-phenylbenzoyl methanthiol, the CPCM model can perfectly describe the solvation effects of methanol. Methanol may stabilize the excitation states, but also protects the resulting radical products from recombination.