Adsorption of CO_(2) on MgAl layered double hydroxides: Effect of intercalated anion and alkaline etching time

The adsorption of CO_(2) on MgAl layered double hydroxides(MgAl-LDHs) based adsorbents has been an effective way to capture CO_(2),however the adsorption capacity was hampered due to the pore structure and the dispersibility of adsorption active sites.To address the problem,we investigate the effect of intercalated anion and alkaline etching time on the structure,morphology and CO_(2) uptake performances of MgAl-LDHs.MgAl-LDHs are synthesized by the onepot hydrothermal method,followed by alkaline etching of NaOH,and characterized by x-ray diffraction,N_(2) adsorption,scanning electron microscopy and Fourier transform infrared spectroscopy.The CO_(2) adsorption tests of the samples are performed on a thermogravimetric analyzer,and the adsorption data are fitted by the first-order,pseudo-second-order and Elovich models,respectively.The results demonstrate that among the three intercalated samples,MgAl(Cl) using chloride salts as precursors possesses the highest adsorption capacity of CO_(2),owing to high crystallinity and porous structure,while MgAl(Ac) employing acetate salts as precursors displays the lowest CO_(2) uptake because of poor crystallinity,disorderly stacked structure and unsatisfactory pore structure.With regard to alkaline etching,the surface of the treated MgAl(Cl) is partly corroded,thus the specific surface area and pore volume increase,which is conducive to the exposure of adsorption active sites.Correspondingly,the adsorption performance of the alkaline-etched adsorbents is significantly improved,and MgAl(Cl)-6 has the highest CO_(2) uptake.With the alkaline etching time further increasing,the CO_(2) adsorption capacity of MgAl(Cl)-9 sharply decreases,mainly due to the collapse of pore structure and the fragmentized sheet-structure.Hence,the CO_(2) adsorption performance is greatly influenced by alkaline etching time,and appropriate alkaline etching time can facilitate the contact between CO_(2) molecules and the adsorbent.

Maskless fabrication of quasi-omnidirectional V-groove solar cells using an alkaline solution-based method

Silicon passivated emitter and rear contact(PERC) solar cells with V-groove texture were fabricated using maskless alkaline solution etching with in-house developed additive. Compared with the traditional pyramid texture, the V-groove texture possesses superior effective minority carrier lifetime, enhanced p–n junction quality and better applied filling factor(FF). In addition, a V-groove texture can greatly reduce the shading area and edge damage of front Ag electrodes when the V-groove direction is parallel to the gridline electrodes. Due to these factors, the V-groove solar cells have a higher efficiency(21.78%) than pyramid solar cells(21.62%). Interestingly, external quantum efficiency(EQE) and reflectance of the V-groove solar cells exhibit a slight decrease when the incident light angle(θ) is increased from 0° to 75°, which confirms the excellent quasi omnidirectionality of the V-groove solar cells. The proposed V-groove solar cell design shows a 2.84% relative enhancement of energy output over traditional pyramid solar cells.

Construction of monodispersed single-crystalline hierarchical ZSM-5 nanosheets via anisotropic etching

Hierarchical zeolites and single-crystalline zeolite nanosheets(NSs)have been recognized as two separate types of targeting porous materials to overcome the diffusion limitations of traditional bulk zeolites.The synthesis of uniform single-crystalline hierarchical zeolite NSs featured with NS morphology and interconnected mesoporosity,remains rarely reported.In this work,we prepared ZSM-5 zeolites with the above microstructural features via simple alkaline etching.Moreover,both their microstructure and acid strength could be accurately tuned with this approach,resulting in not only higher conversion rate and BTX selectivity but also superior anti-coking performance in the subsequent methanol aromatization reaction.

Effect of Surface Pretreatment on Adhesive Properties of Aluminum Alloys

The lap-shear strength and durability of adhesive bonded AI alloy joints with different pretreatments were studied by the lap-shear test and wedge test. The results indicate that the maximum lap-shear strength and durability of the bonding joints pretreated by different processes are influenced by the grade of abrasive papers and can be obviously improved by phosphoric acid anodizing. Alkali etching can obviously improve the durability of bonding joints although it slightly influences the maximum lap-shear strength. The process which is composed of grit-finishing, acetone degreasing, alkali etching and phosphoric acid anodizing, provides a better adhesive bonding property of Al alloy.

碱刻蚀法构建膨化FexCoyNi1-x-yP四元阵列及其高效裂解水性能

设计和构建低成本、高效、高稳定性双功能电催化剂用于全解水生产氢气燃料是非常吸引人的研究,同时也充满挑战.我们精心构建了膨化四元FexCoyNi1-x-yP纳米阵列作为双功能电催化剂用于全解水.通过引入铁元素调节磷化镍钴的电子结构,可增加磷和金属的正电荷分布,从而可实现电催化析氢过程中对氢原子吸附脱附平衡,有利于水分子的吸附和解离.在电子调控的基础上,我们采用动力学控制碱刻蚀的方法优化催化剂的形貌结构,获得了膨化纳米阵列.膨化结构具有丰富的孔结构、空腔以及晶格缺陷,有利于更多活性位点的暴露和传质.膨化FexCoyNi1-x-yP只需25和230 mV过电势即可分别实现产氢和产氧.利用膨化FexCoyNi1-x-yP作为阳极和阴极搭建的电解池只需1.48 V即可实现全解水,并在较高电流中表现出优异的稳定性.我们期望协同优化电子和形貌结构促进电催化反应过程的研究思路对廉价高效稳定双功能电催化剂的研究有所启发.