Facile Synthesis of Cuprous Oxide/Gold Nanocomposites for Nonenzymatic Amperometric Sensing of Hydrogen Peroxide

In this work, a facile preparation method of cuprous oxide/gold (Cu₂O/Au) nanocomposite was successfully developed. The process consisted of one‐pot co‐reduction of HAuCl₄ and CuSO₄ using ascorbic acid (AA) as a reducing agent at room temperature under magnetic stirring. The structures and compositions of the as‐prepared products were characterized by SEM, EDS, and XRD. Cyclic voltammetry and chronopotentiometry studies revealed that the as‐prepared cubic Cu₂O/Au nanocomposites showed enhanced performance towards the non‐enzymatic catalytic reduction of hydrogen peroxide (H₂O₂) when compared to single‐component Cu₂O nanocubes. The linear range of H₂O₂ determination spanned over 4 orders of magnitude (1 μM∼16.7 mM) and the detection limit was low as 0.45 μM (S/N=3). The enhanced performance of cubic Cu₂O/Au was attributed to: i) the synergistic effect between Cu₂O and Au, ii) the increase in surface area induced by the reduced size of the nanocubes, and iii) the improved electrical conductivity due to the presence of Au in the particles. Overall, the cubic Cu₂O/Au nanocomposites prepared by the proposed method hold great promise for future practical use in H₂O₂ detection.     

Photoinduced electron transfer in a triarylamine-organoboron-Ru(2,2′-bipyridine)32+ compound

Long-range electron transfer reactions play a key role in biological photosynthesis, and they are likely to play an important role for future artificial photosynthetic endeavors as well. The possibility to control the rates for long-range electron transfer with external stimuli is of particular interest in this context. In the work presented herein, we explored a donor–bridge–acceptor compound in which intramolecular electron transfer from a triarylamine donor to a photoexcited Ru(bpy)₃²⁺ (bpy = 2,2′-bipyridine) acceptor occurs across an organoboron bridge over a distance of approximately 22 Å. Fluoride has a high binding affinity to the organoboron bridge in apolar solutions, and the resulting organofluoroborate has a significantly different electronic structure. We explored to what extent the change from an electron-deficient organoboron wire to an electron-rich organofluoroborate bridge affects long-range electron transfer between the distant triarylamine donor and the Ru(bpy)₃²⁺ acceptor.     

Photochemical synthesis: Using light to build C–C bonds under mild conditions

A review of recent advancements in metal-free arylations via photogenerated triplet aryl cations and decatungstate anion ([W₁₀O₃₂]⁴⁻) photocatalyzed C–C bond formation is reported herein. These approaches are two examples of the great potentialities of photons as green activants in organic synthesis, allowing the functionalization of different chemical substrates under mild conditions (room temperature, aqueous solvents, absence of aggressive and unstable reactants and of expensive transition metal-based catalysts, and chance to use solar light as the energy source).     

Host (dealuminated Y zeolite)–guest (zirconium tetraphenylporphyrin) nanocomposite materials. An efficient catalyst in the oximation of aldehydes

In this research, zirconium tetraphenylporphyrin encapsulated into dealuminated Y zeolite (ZrTPP–DAZY) was prepared through a template synthesis method. This heterogeneous catalyst was characterized by XRD, FT-IR, DRS, UV–Vis, EDX and FESEM techniques. The amount of ZrTPP in the nanocage of dealuminated Y zeolite was estimated to be 0.0156 g/g of support. This catalytic system was employed for an efficient oximation of aldehydes under magnetic stirring conditions at room temperature and the corresponding products were obtained in 50–90% yields. This catalytic system also indicated good shape selectivity towards linear aldehydes. ZrTPP–DAZY was reused several times without any significant loss in catalytic activity.     

Cu(II) immobilized on Fe3O4–diethylenetriamine: A new magnetically recoverable catalyst for the synthesis of 2,3‐dihydroquinazolin‐4(1H)‐ones and oxidative coupling of thiols

Cu(II) immobilized on Fe₃O₄–diethylenetriamine was designed as a new, inexpensive and efficient heterogeneous catalyst for the synthesis of 2,3‐dihydroquinazolin‐4(1H )‐ones and the oxidative coupling of thiols. The structure of the nanomagnetic catalyst was comprehensively characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, vibrating sample magnetometry, thermogravimetric analysis, X‐ray diffraction and atomic absorption spectroscopy. Simple preparation of the catalyst from commercially available materials, high catalytic activity, simple operation, high yields, use of green solvents, easy magnetic separation and reusability of the catalyst with unaltered activity make our protocol a green and feasible synthetic strategy.     

Ultrasonic treatment of water contaminated with various pollutants onto copper nanowires loaded on activated carbon using response surface methodology and artificial intelligent

In this study, the potential application of copper nanowires loaded on activated carbon for simultaneous removal of Disulfine blue (DB), Crystal violet (CV) and Sunset yellow (SY) has been described. The relation between adsorption properties with variables such as solution pH, adsorbent value, contact time and initial dyes concentration was investigated and optimized. A three‐layer artificial neural network (ANN) model was utilized to predict dyes removal (%) by adsorbent following conduction of experiments. The training of network at above mention experimental data confirms its ability to forecast the removal performance with a linear transfer function (purelin) at output layer. The Levenberg–Marquardt algorithm and tangent sigmoid transfer function (tansig) with 16 neurons at the hidden layer was applied. Parameters were optimized by central composite design (CCD) combined with response surface methodology (RSM) and desirability function. The accuracy of ANN was judged according to both MSE and AAD% at optimal conditions and results indicate its superiority to RSM model in term of higher R² and lower AAD% values. This observation was also corroborated by the parity plots between the predicted and experimental values. The ANN model was better in both data fitting and prediction capability in comparison to RSM model.     

Nitrogen‐Doped Mesoporous Carbon‐Encapsulated MoO2 Nanobelts as a High‐Capacity and Stable Host for Lithium‐Ion Storage

N‐doped mesoporous carbon‐capped MoO₂ nanobelts (designated as MoO₂@NC) were synthesized and applied to lithium‐ion storage. Owing to the stable core–shell structural framework and conductive mesoporous carbon matrix, the as‐prepared MoO₂@NC shows a high specific capacity of around 700 mA h g⁻¹ at a current of 0.5 A g⁻¹, excellent cycling stability up to 100 cycles, and superior rate performance. The N‐doped mesoporous carbon can greatly improve the conductivity and provide uninhibited conducting pathways for fast charge transfer and transport. Moreover, the core–shell structure improved the structural integrity, leading to a high stability during the cycling process. All of these merits make the MoO₂@NC to be a suitable and promising material for lithium ion battery.     

预嵌锂用穿孔集流体对锂离子电容器电化学性能的影响

将石墨涂覆于传统铜箔(CCC)与穿孔铜箔(PCC)集流体表面,通过内部短路的方式进行预嵌锂处理,再以商业化的活性炭及预锂化的石墨分别为正、负极材料组装成锂离子电容器(LIC)。以PCC为集流体的LIC在0.1和2.0 A?g~(-1)的电流密度下,能量密度分别为118.2和51.7 Wh?kg~(-1),并且在0.5 A?g~(-1)的电流密度下循环1000次后的能量密度保持率为90%;以CCC为集流体的LIC在0.1和2.0 A?g~(-1)的电流密度下的能量密度分别为125.5和43.3 Wh?kg~(-1),在同等电流密度下2.0-3.8 V之间循环1000次后的能量密度保持率仅为73.2%。进一步研究表明,石墨采用PCC在预嵌锂的过程中避免了金属锂沉积,生成了均一且稳定的固体电解质膜(SEI),有效防止充放电过程中SEI膨胀,活性物质与集流体间粘结力降低,活性物质脱落等现象发生。因此,LIC通过PCC完成预嵌锂后的自放电及内阻更小,具有更佳的倍率性能和循环性能。     

蒸氨法制备铜硅催化剂的二甲醚水蒸气重整制氢性能

采用蒸氨法制备出不同Cu负载量的xCu/SiO_2-AE催化剂,并将其用于二甲醚水蒸气重整制氢反应。当Cu负载量为30%(w)时,30Cu/SiO_2-AE催化剂表现出最佳的催化性能。结果显示,该方法制备的催化剂表面具有高度分散的CuO和层状硅酸铜物相,经还原后分别形成Cu~0和Cu~+物种。与常规浸渍法制备的30Cu/SiO_2-IM催化剂相比,蒸氨法制备的30Cu/SiO_2-AE催化剂具有优异的催化稳定性和活性,这与其独特的层状结构和表面Cu~0与Cu~+之间的协同作用相关。