Yuhao Cheng,Xiongfei Xie,Shuai Li,Qingqing Qiu,Yao Liu
Crystal morphology in supersaturated copper sulfate (CuSO 4 ) solutions in the presence of acidic polymers is investigated using the non-photochemical laser-induced nucleation (NPLIN) technique. The solubility of copper sulfate in different solvents is measured using the continuous addition method, which is detailed in the Supporting Information. The optimum range of laser power is selected based on a suitable nucleation probability and desirable crystalline morphology. Two different forms of copper sulfate crystals are obtained by a nanosecond pulsed laser with the wavelength of 532 nm. The experimental results show that the addition of impurities increases the probability of nucleation of copper sulfate crystals during nanosecond laser pulse irradiation, which is consistent with the nanoparticle heating mechanism for NPLIN; the addition of acidic polymer can control crystal growth rate of each crystal surface. All CuSO 4 crystals obtained from the technique of NPLIN are revealed as copper sulfate pentahydrate (CuSO 4 ·5H 2 O) through powder X-ray diffraction analysis. After the sample solution is added with polyacrylic acid, the crystalline morphology changes from polyhedral 3D morphology to long rod morphology. Based on this, different kinds of impurities and acidic polymers are applied in order to achieve a controllable approach on nucleation probability and crystalline morphology of CuSO 4 ·5H 2 O crystals. The effects of impurities and acidic polymers on crystals are analyzed to study the underlying mechanism of NPLIN and morphological differences.
Lin Zhang,Xingda An,Kai Feng,Juan Li,Jingjing Liu,Jinxing Chen,Chaoran Li,Xiaohong Zhang,Le He
The interest in introducing light into heterogeneous catalysis is driven not only by the urgent need of replacing fossil energy but also by the promise of controlling product selectivity by light. The product selectivity differences observed in recent studies between light and dark reactions are often attributed to photochemical effects. Here, we report the discovery of a non-photochemical origin of selectivity difference, at essentially the same CO2 conversion rate, between photothermal and thermal CO2 hydrogenation reactions over a Ru/TiO2–x catalyst. While the presence of the photochemical effect from ultraviolet light is confirmed, it merely enhances the catalytic activity. Systematic investigation reveals that the gradual formation of an adsorbate-mediated strong metal–support interaction under catalytic conditions is responsible for the variation in the catalytic selectivity. We demonstrate that differences in product selectivity under light/dark reactions do not necessarily originate from photochemical effects. Our study refines the basis for determining photochemical effects and highlights the importance of excluding non-photochemical effects in mechanistic studies of light-controlled product selectivity.
Titanium dioxide nanoparticle (nano-TiO 2 ), as an excellent UV absorbent and photo-catalyst, has been widely applied in modern industry, thus inevitably discharged into environment. We proposed that nano-TiO 2 in soil can promote crop yield through photosynthetic and metabolic disturbance, therefore, we investigated the effects of nano-TiO 2 exposure on related physiologic-biochemical properties of rice ( Oryza sativa L.). Results showed that rice biomass was increased >30% at every applied dosage (0.1–100 mg/L) of nano-TiO 2 . The actual photosynthetic rate (Y(II)) significantly increased by 10.0% and 17.2% in the treatments of 10 and 100 mg/L respectively, indicating an increased energy production from photosynthesis. Besides, non-photochemical quenching (Y(NPQ)) significantly decreased by 19.8%–26.0% of the control in all treatments respectively, representing a decline in heat dissipation. Detailed metabolism fingerprinting further revealed that a fortified transformation of monosaccharides (D-fructose, D-galactose, and D-talose) to disaccharides (D-cellobiose, and D-lactose) was accompanied with a weakened citric acid cycle, confirming the decrease of energy consumption in metabolism. All these results elucidated that nano-TiO 2 promoted rice growth through the upregulation of energy storage in photosynthesis and the downregulation of energy consumption in metabolism. This study provides a mechanistic understanding of the stress-response hormesis of rice after exposure to nano-TiO 2 , and provides worthy information on the potential application and risk of nanomaterials in agricultural production.
危险品化学品经营许可证（带存储）