The Chemical State of a Silver-Copper Complex Image Formed during the Electroless Copper Deposition

By means of electroless copper deposition method a complex image has been fabricated in a mixture of cupric sulphate and formaldehyde, the surface and subsurface properties of which has been studied in detail by X-ray photoelectron spectroscopy (XPS) combined with sputter depth profiling technique analyzing distribution and chemical state of copper and silver. Depth profiling by XPS in conjunction with Ar+ sputtering shows that the catalytic activity of silver persists, catalyzing reduction of copper. The integral areas of spectra Ag3d after electroless copper deposition for 5 min at different sputtering times demonstrate that the amount of silver at the surface is greater than that in the interior. And then, the quite likely reasonable explanations are provided for the result. Additionally, the chemical shift of Ag3d XPS and deconvolution of Ag3d XPS spectrum have been also analyzed respectively at length.

Optical properties of stacked liquid crystal superstructures with opposite chirality [Invited]

Cholesteric liquid crystal (CLC) has been widely used in flat optical elements due to the Pancharatnam–Berry(PB) phase modulation. In order to achieve PB phase modulation for both circular polarizations, it is natural to come up with stacking CLCs with opposite chirality. Here, various optical properties of diverse CLC stacking structures are systematically investigated by numerical calculations. With the thickness of the CLC sublayers becoming smaller, the reflection bandgap splits into three main parts, and the rotatory dispersion gradually becomes negligible. Vector beams provide a more intuitive verification. These results provide theoretical guidance for future studies on stacked chiral anisotropic media.

低碳生物合成:机遇与挑战

低碳生物合成以CO_(2)等可再生碳资源为原料,以生物体为工具进行物质合成,是节约化石原料的可持续路线,是现有化工、农业产品的替代性低碳生产新模式,是CO_(2)高效利用转化的工业碳汇新路径.目前低碳生物合成的产业影响力、技术经济性等还无法与传统路线竞争,CO_(2)等可再生碳资源的生物工业利用范围、转化效率、生物合成的工业能力等是亟待解决的关键科技问题.快速发展的工程生物学是对生物体结构和功能进行工程化设计再造的新生物学领域,正在推动生物学工程化新范式,将从根本上提升生物体将CO_(2)等可再生碳资源转化为生物基产品的能力,引发生物工业的颠覆式突破.针对碳达峰、碳中和战略目标实施,本文分析了低碳生物合成的发展机遇,综述了低碳生物合成国内外的科技进展与发展趋势,探讨了低碳生物合成的科技挑战与重点方向,最后对发展方向提出了相关建议.

Chemisorption solid materials for hydrogen storage near ambient temperature:A review

Solid chemisorption technologies for hydrogen storage,especially high-efficiency hydrogen storage of fuel cells in near ambient temperature zone defined from−20 to 100℃,have a great application potential for realizing the global goal of carbon dioxide emission reduction and vision of carbon neutrality.However,there are several challenges to be solved at near ambient temperature,i.e.,unclear hydrogen storage mechanism,low sorption capacity,poor sorption kinetics,and complicated synthetic procedures.In this review,the characteristics and modification methods of chemisorption hydrogen storage materials at near ambient temperature are discussed.The interaction between hydrogen and materials is analyzed,including the microscopic,thermodynamic,and mechanical properties.Based on the classification of hydrogen storage metals,the operation temperature zone and temperature shifting methods are discussed.A series of modification and reprocessing methods are summarized,including preparation,synthesis,simulation,and experimental analysis.Finally,perspectives on advanced solid chemisorption materials promising for efficient and scalable hydrogen storage systems are provided.

Molecular simulation on carbon dioxide capture performance for carbons doped with various elements

Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perfor-mance by doping hetero elements due to the rapid reaction kinetics and low costs.Herein,sorption capacity and selectivity for CO_(2)and N 2 on carbon-based sorbents doped with elements such as nitrogen,sulfur,phosphorus,and boron,are evaluated and compared using the grand canonical Monte Carlo(GCMC)method,the universal force field(UFF),and transferable potentials for phase equilibria(TraPPE).The sorption capacities of N-doped porous carbons(PCs)at 50℃were 76.1%,70.7%,50.6%,and 35.7%higher than those of pure PCs,S-doped PCs,P-doped PCs,and B-doped PCs,respectively.Its sorption selectivity at 50℃was approximately 14.0,nearly twice that of pure PCs or other hetero-element-doped PCs.The N-doped PCs showed the largest sorption heat at 50℃among all the PCs,approximately 20.6 kJ·mol^(−1),which was 9.7%−25.5%higher than that of the pure PCs under post-combustion conditions.Additionally,with the product purity of 41.7 vol.%−75.9 vol.%for vacuum pressure swing sorption,and 53.4 vol.%−83.6 vol.%for temperature swing sorption,the latter is more suitable for post-combustion conditions than pressure-swing sorption.

Hydrothermal synthesis, structures and properties of metal phosphonates based on m-xylylenediphosphonic acid

In this work, a series of new metal phosphonates were hydrothermally synthesized and structurally characterized based on m-xylylenediphosphonic acids(H4L), including[M(H2L)(bpy)](M = Mn 1, Co 2), [MH2L)(phen)](M = Co3, Cu 4), and [Cu2(H2L)2(bpy00)2] 5(bpy = 2,20-bipyridine,phen = 1,10-phenanthroline, bpy00= 4,40-dimethyl-2,20-bipyridine). X-ray diffraction indicated that compounds 1 and2 were isomorphic. Complexes 3 and 4 were shown to crystallize in different space groups but had similar crystallographic units. In the complexes, H4 L was seen to partially deprotonate to afford H2L2-. The H2L2-ligands in 1–4functioned as tetradentate ligands with each phosphonate group adopting bidentate coordination mode with two M centers to generate a 2D layer. In addition, the H2L2-anions in5 functioned as tridentate ligands with one phosphonate group adopting the bidentate mode and another phosphonate group adopti ng the monodentate mode, thus linking three Cu atoms to provide a 1D chain. The IR and thermal stabilities of these compounds were subsequently examined.