Effect of MnOx phase on Pt-based catalyst for enhancing CO/C3H6/NO oxidation performance

To improve the fuel economy, it is crucial to promote the low-temperature performance in eliminating diesel emissions. The work investigates the impact of different MnO₂/Mn₂O₃ phase ratio on the low-temperature performance of Pt-based monolithic diesel oxidation catalyst. Near equal ratio of MnO_x phase could form the three-phase (platinum, MnO₂, Mn₂O₃) interfacial structure, leading to the smaller platinum particle size and exhibiting the higher interface rate (1.6–11.1 times) than other mono-manganese oxide with platinum. Besides, the higher oxygen mobility and more active oxygen species could be contributed to the positive effect of Pt/MnO_x interface, which are prevalent to activate the reactant and greatly enhance the TOF value (1.4–20.8 times). The results imply that the modification of multi-phase metal/oxide interface is potential in dispersing platinum for greatly enhancing the catalytic efficiency.     

混炼方式对螺旋纳米碳纤维增强天然橡胶复合材料力学性能的影响

采用干法和湿法两种混炼工艺制备了螺旋纳米碳纤维(HCNFs)/炭黑(CB)/天然橡胶(NR)复合材料,通过扫描电镜、拉伸试验机和应变扫描仪分别对所制备复合材料的界面形貌、力学性能和Payne效应进行了测试分析,考察了混炼方式对复合材料宏观力学性能及Payne效应的影响。结果表明,与纯CB填料相比,在干湿两种混炼方式下,添加适量的HCNFs(1～6份)能提高HCNFs/CB/NR复合材料的300%定伸应力、扯断伸长率、拉伸强度和硬度。与干法混炼相比,湿法混炼能明显增强HCNFs/CB/NR复合材料的Payne效应,并提升在HCNFs高添加量(2～6份)条件下的拉伸强度和扯断伸长率,这主要源于湿法混炼能够有效改善HCNFs在橡胶基质中的分散性。     

Mechanochemically assisted fabrication of ultrafine Pd nanoparticles on natural waste-derived nitrogen-doped porous carbon for the efficient formic acid decomposition

Utilizing natural waste as carbon source to prepare porous carbon with ultrahigh surface area and developing a facile protocol to synthesize supported metal nanoparticles toward an efficient formic acid (FA) decomposition are vital but remains challenging. Here, discarded ginkgo leaves were utilized as carbon source to prepare ginkgo leaf-derived porous carbon (GLPC) with an ultrahigh surface area of 3851 m²/g. Based on the as-prepared nitrogen-doped GLPC (N-GLPC) after “soft” nitriding, a facile solid-state reduction strategy with mortar-pestle grinding and without the use of any organic solvent and stabilizing ligand was developed to synthesize ultrafine and well-distributed Pd nanoparticles (NPs) with a diameter of 2.7 ± 0.7 nm. The “soft” nitriding temperature and addition of base during preparation played vital roles in the activity of the fabricated catalysts. The Pd/N-GLPC-350 exhibited the highest catalytic activity toward decomposing FA, achieving a high turnover frequency of 2952 h^?1 at 333 K. The Pd/N-GLPC-350 was quite stable and could be reused at least five times without evident activity loss. This study provides a facile solid-state reduction protocol with mortar-pestle grinding to synthesize metal NPs by using natural waste-derived porous carbon as support toward efficient FA decomposition.     

以箭竹为辅料酿造小曲酒工艺优化研究

以香蕉、芒果、六堡茶汤为主要原料，佰生优益生菌果蔬酵素发酵菌为菌种，研制发酵型香蕉复合果汁饮料，通过单因素和响应面试验确定最优发酵工艺条件，并对其可溶性固形物、蛋白质等营养活性成分含量变化情况进行研究。结果表明：最佳发酵工艺条件为香蕉浆50%，芒果汁5%，白砂糖添加量6%、佰生优益生菌果蔬酵素发酵菌接种量0.04%、茶汤添加量5.0%，发酵时间5.0 d，发酵温度34 ℃，此条件下得到的饮料色泽淡黄透亮、具有香蕉和芒果固有的浓郁香味，酸甜适中，其可溶性固形物、可滴定酸度、蛋白质、总糖、总多酚的含量分别为16.80%、1.20 g/kg、10.90 mg/100 g、9.91 g/100 g、0.38 mg/mL。其中总糖和总多酚在整个发酵过程中变化较小，处于稳定状态，而可滴定酸度、蛋白质呈明显上升状态，可溶性固形物变化不稳定，总体呈上升趋势。     

Carbon nanotube filter for heavy metal ion adsorption

This study investigated carbon nanotube filtration technology using catalyst particles supported on silicalite-1–biomorphic carbon materials (BCMs). Aqueous solutions of Mn(II), Cu(II), Cr(III), Cd(II), and Pb(II) were used to test the efficiency of heavy metal ions removal. Carbon nanotubes (CNTs) were synthesized and grown on BCMs by the chemical vapor deposition method catalyzed with the catalyst (Co, Fe, and Ni). The synthesized CNTs with Co– and Fe– nanoparticles were typically multi-walled carbon nanotubes, and they showed good crystallinity (I_D/I_G = 1.05) and yield of (11.10 and 8.86) %. The removal efficiency of Mn(II), Cu(II), Cr(III), Cd(II), and Pb(II) ions using Co-catalyzed CNT filter was 97.57%, 98.01%, 97.89%, 97.42%, and 99.99%, respectively.     

感悟好白酒蕴含的曼妙画卷

从白酒产区、酿酒原料、发酵容器、酿造工艺等角度解析了它们对白酒品质的影响,并揭示了好白酒内在品质应该具备的科学特性,进而彰显了“好白酒犹如一副曼妙画卷”的文化之美。     

The performance of green carbon as a backbone for hydrogen storage materials

We investigate the use of carbonized bamboo, which has an organic porous structure, as a hydrogen storage material. Bamboo samples were thermally treated at 800, 900, 1000, and 1100 °C for 24 h. The pore size and hydrogen storage capacity of each sample were measured by N₂ and H₂ gas sorption up to 1.13 bar at 77 K. The maximum hydrogen storage was exhibited by the sample treated at 900 °C, which reached 1.35 wt% at 1.13 bar/77 K. The results showed that the bamboo, one of the green carbons, has the potential to be used as an environmental-friendly carbon backbone for hybrid hydrogen storage materials.     

Solar driven MgO/Mg based methane reforming and water splitting process: A thermodynamic inspection

The thermodynamic efficiency analysis of the MgO/Mg based CH₄ reforming and H₂O splitting process is performed in this paper. The study is conducted by considering two process configurations, namely, a) MgO/Mg based open process where Mg and syngas is produced (MS process), and b) MgO/Mg based semi-open process where syngas and H₂ is generated (MSH process). The thermodynamic equilibrium analysis indicate that the best possible thermal reduction temperature for both processes is 2100 K and, in case of the MSH process, the water splitting step is feasible in the range of 500–900 K. As per the findings, for the MS process, the solar energy required to drive the process increases by 958.2 kW as the CH₄/MgO ratio upsurges from 0.1 to 1. For the MSH process, the minimum amount of solar energy needed to run the process i.e., 1203.1 kW can be accomplished at water splitting temperature of 900 K and CH₄/MgO molar ratio = 1. Based on the solar-to-fuel energy conversion efficiency, the MSH process appears to be more advantageous (54.5%) than the MS process (41.3%). The solar-to-fuel energy conversion efficiency of the MSH process can be further enhanced up to 65.6% by reclaiming 50% of the heat dissipated by the coolers and WS reactor.     

Deformation mechanism in NiAl single crystals at low temperatures

Available data on the temperature dependence of yield stress and of associated activation volume of high-purity NiAl single crystals between 76 and 205 K have been analyzed within the framework of a solid-solution hardening model, which is based on the concept of depinning of an edge-dislocation segment from several randomly dispersed, isolated, point defects simultaneously. The vacancies in NiAl single crystals act as point-defect obstacles to the stress-assisted thermally-activated glide of edge dislocations, and their concentration is estimated as about 10 at.%. The product of yield stress and associated activation volume (≈0.146 eV) is found to be independent of temperature and yield stress, as envisaged in the model.