查找使用阿拉丁产品的科研文献

A novel high pseudo-capacitive contribution anode in K-ion battery: Porous TiNbO4/C nanofibers

Die Su,Jianping Yang,Qingshui Hong,Min Yang,Jiaxing Wen,Qianfu Wang,Hai Hu,Li Liu,Xiukang Yang

Pseudo-capacitive materials show long cycling life as anode of K-ion battery (KIBs), yet low specific capacity and poor rate performance. Herein, the porous TiNbO 4 /C nanofibers (denoted as TNO/C) are synthesized via electro-spinning. Abundant oxygen vacancies and large specific surface area make the sample exudes high specific capacity and good rate performance. After optimizing the calcination temperature, it is found that the porous TiNbO 4 /C nanofibers at 700 °C (denoted as TNO/C-700) can deliver the specific discharge capacity of 250.4 mAh g −1 in K-ion half cell and demonstrate good cycle stability for 100 cycles in K-ion full cell in 100 mA g − 1 . Even in 5 A g − 1 , the discharge capacity of TNO/C-700 electrodes is still 116.7 mAh g − 1 at rate performance. Ex-situ XRD results show that this TNO/C-700 electrode is associated with pseudo-capacitive effect and insertion/de-insertion process. The TNO/C-700 electrode exhibits a high pseudo-capacitive contribution, which can reach to 85.0% at 3 mV s −1 . This novel high pseudo-capacitive contribution anode material provides more possibilities for the selection in KIBs.

Isopiestic Measurements of Water Activity for the NaCl–KCl–MgCl2–H2O Systems at 323.15 K

Haijun Han,Dongdong Li,Lijiang Guo,Yan Yao,Haitang Yang,Dewen Zeng

Water activity for binary KCl–H2O, NaCl–H2O and MgCl2–H2O, as well as two ternary NaCl–MgCl2–H2O and KCl–MgCl2–H2O, systems has been measured by using an isopiestic method at 323.15 K. The isopiestic results obtained show that the isopiestic composition lines of the NaCl–MgCl2–H2O system was found to obey the Zdanovskii rule, whereas the KCl–MgCl2–H2O system was observed to deviate slightly. The experimental water activities determined were applied to regress the parameters of the Pitzer model with a good agreement. The model with new parameters is validated by comparing water activity predictions with those given in the literature and not used in the parametrization process and calculating the solubility of the NaCl–MgCl2–H2O and KCl–MgCl2–H2O systems at various temperatures with the comparison of literature values.

Influence of calcination temperature on the fluorescence and magnetic properties of Gd2O3:Tb3+, K+ nanoparticles

Hao Zhou,Hao Zhou,Rong Fu,Rong Fu,Chunlin Yang,Meigui Ou,Meigui Ou,Chengjie Xue,Chengjie Xue

High-Performance PB-KZnHCF Electrochromic Devices Enabled by a Synergistic K+/Zn2+ Dual-Ion Electrolyte

Xiaoqian Tan,Yiyue Luo,Zehao Yu,Menghan Li,Chao Wang,Tingxin Ma,Wei Liu,Fuyi Jiang,Litao Kang

A K⁺/Zn²⁺ dual-ion electrolyte is proposed to suppress dissolution and stabilize KZnHCF counter electrodes. • The electrolyte ensures high electrochemical activity for both the PB working electrode and the KZnHCF counter electrode. • The optimized PB-KZnHCF device achieves a large optical modulation, fast switching speed, and excellent cycling stability. KZnHCF (K 2 Zn 3 [Fe(CN) 6 ] 2 ), a typical Prussian blue analog (PBAs), exhibits high transparency regardless of the redox states, making it an ideal transparent counter electrode material for electrochromic devices. However, its cycling durability is seriously limited by stability issues deriving from material dissolution. In this work, we propose a K + /Zn 2+ dual-cation electrolyte to enhance the cycling durability of KZnHCF by changing the Zn 2+ dissolution equilibrium between the electrolyte and the electrode. This electrolyte formulation is also compatible with the Prussian Blue (PB) electrochromic electrodes, enabling excellent electrochromic performance. Based on these merits, a high-performance electrochromic device is constructed by pairing the PB working electrode with the KZnHCF counter electrode in the K + /Zn 2+ electrolyte. This device demonstrates a desirable optical modulation of 52.7% at 633 nm with a coloration and bleaching response time of 5 and 14 s, respectively. After 1000 cycles, 77.8% of the initial optical modulation retains, indicating a decent cycling stability. This work underscores the promise of electrolyte engineering in addressing stability challenges of electrodes, offering a viable pathway to improve the performance of Prussian blue (PB)-based electrochromic devices. Download: Download high-res image (107KB) Download: Download full-size image

Sustained high-temperature fluorescence in bulk carbon nitride enabled by K/Na dual-alkali regulation

Luo Jian,Li Wenbin,Jin Chenkai,Huang Juncheng,Fang Chao,Song Lixin,Na Haining,Zhu Jin

Rare-earth-free carbon nitride luminescent materials that remain bright during prolonged high-temperature operation are highly desirable for harsh-environment optoelectronics, yet their emission is often limited by thermally activated non-radiative pathways and accelerated weathering under ultraviolet (UV) irradiation. Here, we report a K/Na co-regulated carbon nitride (K/Na-CN) prepared via a solid-state route. Temperature-dependent photoluminescence (PL) measurements show a well-preserved emission band with only limited chromaticity deviation over a broad heating window. Under vacuum, K/Na-CN retains ~ 50% of its initial PL intensity at 300 °C and maintains ~ 70% PL intensity after holding at 300 °C for 60 min. During UV aging (0–192h), the powder PL intensity increases to ~ 1.7–1.8 × at 48h, reaches a maximum of ~ 2.4 × at 144h, and remains at ~ 1.5 × after 192h, which indicates robust emissive states despite irradiation-driven defect-state rebalancing. After incorporation of K/Na-CN into PMMA to prepare transparent luminescent plates, at an optimized loading, the composite shows the best dispersion and maintains high optical clarity (visible transmittance > 80% and reflectance < 12%), while providing improved UV service behavior. After UV exposure, the composite emission exhibits a systematic blue shift from ~ 530 nm (0h) to ~ 500 nm (48 h) and ~ 480 nm (96h). Meanwhile, the weak intensity gap is consistent with bulk particle aggregation and inner-filter effects limiting the effective radiative gain. Overall, K/Na-CN combines sustained high-temperature fluorescence with UV-tolerant performance in both powders and transparent polymer composites, offering a practical platform for long-service luminescent components operating under heat and irradiation stress.

Water Activity Measurement and Thermodynamic Modeling for the System Na2CO3–Cs2CO3–H2O at 308.15 K

Jia Xu,Xun Wang,Tongqing Wang,Ziwei Hu,Ruyi Lin,Dan Li,Yong Ma,Lingzong Meng,Yafei Guo,Guangli Zhou,Tianlong Deng

The isopiestic equilibria in the system Na2CO3–Cs2CO3–H2O at 308.15 K were investigated with an improved isopiestic method with a modified gravimetric isopiestic apparatus. The water activities and osmotic coefficients were determined based on the calcium chloride standard reference solution. The equilibrium vapor pressure was calculated with the water activity. Combining the Pitzer binary parameters of Na2CO3, the Pitzer binary parameters β(0), β(1), and Cφ of Cs2CO3 and Pitzer mixing parameters θNa+, Cs+ and ψNa+, Cs+, CO32– were fitted with the experimental osmotic coefficients on the basis of the Pitzer model. The water activities were then calculated by the Pitzer parameters, and the good agreement between the calculated water activities and experimental results of this ternary system indicated that the Pitzer parameters obtained in this work were reliable. The thermodynamic data and Pitzer parameters obtained in this work can provide fundamental thermodynamic data for development of universal chemical models for brine systems containing cesium carbonate.

High-purity KCl prepared with K(cl, Br) solid solution via controlled-coordination of glycerol

Yali Wang,Hongbao Ren,Ruizhi Cui,Bo Zhang,Qiuye Yang,Wu Li

A glycerol-water coordination method was developed to prepare high-pure KCl from K(Cl, Br) solid solutions. • Glycerol inhibits Br − from entering the KCl lattice. 30 wt% mixed solvent shows better separation performance. • KCl with 99.994% purity and 97.30% yield was obtained, while bromide was concentrated in the liquid phase. High-purity KCl is essential for semiconductors and laser crystals, yet even trace bromine severely compromises its performance. During the preparation of KCl via underground brine crystallization, Br − readily enters the KCl lattice to replace Cl − , forming crystals with a single-salt structure rather than a simple mixture. This makes it difficult to use conventional separation methods to produce high-purity KCl. To address this issue, this study proposes a separation strategy that involves intervening in the recrystallization process by regulating coordination interactions within the solvent system, thereby yielding ultra-pure potassium chloride. Systematic studies involving phase equilibrium experiments, solid-liquid phase characterization and molecular simulations indicate that as the number of hydroxyl groups in the alcohol molecule increases, the solvent's separation capacity increases accordingly, with glycerol exhibiting the best performance. As the simplest trihydric alcohol, glycerol's three hydroxyl groups create distinct solvation environments for Cl − and Br − , thereby inhibiting Br − from occupying the KCl lattice during the concentration and crystallization processes. Furthermore, the introduction of 30 wt% mass water inhibits intermolecular hydrogen bonding and self-aggregation of glycerol, releasing free coordination sites and significantly increasing the solubility of KCl in the system (from 1.7 wt% to 9.63 wt%), thereby further optimizing separation efficiency. The separation process, designed based on the phase diagram of the KCl − KBr − Gly(30 wt%) − H₂O system at 298.15 K, enables the efficient recovery of high-purity KCl (purity up to 99.9940%, recovery rate of 97.30%) and the simultaneous enrichment of bromine resources in the liquid phase (bromine content increased from 3.36 wt% to 44.30 wt%).

K/Ni-modified porous catalysts from coal gasification fine slag for biomass tar steam reforming

Daoheng Zhang,Jiawei Zhang,Jian Xing,Zhuozhi Wang,Xingcan Li,Shuai Guo

One-step flotation–activation for CGFS-derived catalysts. • Ni- and K-modified catalysts show distinct reforming pathways. • Ni-based catalysts achieve high tar conversion (97.2%) with coke resistance. • K favors CH 4 formation while Ni enhances H 2 -rich syngas production. Efficient and stable catalysts are essential for biomass-tar reforming in sustainable biomass gasification systems that utilize low-cost solid waste feedstocks. In this study, coal gasification fine slag (CGFS) was processed by saline flotation to enrich the residual carbon fraction and remove ash content, yielding a support material with enhanced catalyst surface area and pore volume. Low-concentration saline flotation produced supports with greater specific surface areas (S BET ), while high-concentration saline flotation yielded catalysts with superior catalytic performance. Catalytic performance was primarily determined by the nature of the metal loading. Ni-loaded catalysts (Ni4) achieved higher tar-conversion rates and CO yields than K-loaded counterparts (K4), with substantially greater H 2 production. Conversely, K4 produced higher CH 4 yields than Ni4, attributable to enhanced high-temperature methanation leading to higher CH 4 selectivity, whereas Ni-based catalysts showed superior overall catalytic performance and anti-coking ability, attributable to their unique FeNi 3 alloy active centers. Furthermore, regeneration tests demonstrated that both Ni4 and K4 catalysts retained considerable tar conversion capability after three reaction–regeneration cycles, highlighting their potential for cyclic utilization. These results demonstrate the potential of CGFS as a low-cost tar conversion catalyst. Download: Download high-res image (462KB) Download: Download full-size image

Cation-self-shielding strategy promises high-voltage all-Prussian-blue-based aqueous K-ion batteries

Guo Qiubo,Han Shuai,Lu Yaxiang,Xiao Ruijuan,Li Jin,Hao Qingli,Rong Xiaohui,Weng Suting,Niu Yaoshen,Ding Feixiang,Yang Yang,Xia Hui,Wang Xuefeng,Xie Fei,Zhou Lin,Hou Xueyan,Li Hong,Huang Xuejie,Chen Liquan,Hu Yong-Sheng

Prussian blue analogues (PBAs) are promising electrode candidates for aqueous batteries because the inevitable interstitial water is generally thought to have little impact on battery performance. Currently, mounting researches have focused on optimizing PBA properties by varying transition metal composition, but less attention has been paid to interstitial water, especially in alkali metal-ion deficient PBAs with large cavities. Here, we employ the water-rich K 0.01 Mn[Cr(CN) 6 ] 0.74 ·4.75H 2 O as the negative electrode to study the effect of interstitial water. It is found that during de-potassiation, the electrode undergoes dehydration, which negatively impacts kinetics, distorts structure, and raises charging potential. A cation-self-shielding strategy involving Dihydroxyacetone (DHA) in the electrolyte to secure the water-rich state is then proposed. The built 1.82 V all-Prussian blue aqueous K-ion battery delivers a high practical specific energy of ~76 Wh kg −1 over 1.5 V (based on the total mass of active materials in both electrodes). This study reveals the significance of interstitial water on the kinetics of PBA negative electrodes and promotes the exploration of water-containing electrodes to develop high-voltage aqueous rechargeable batteries for energy storage applications.

Catalytic Ozone Degradation of Dye Wastewater by CoAl-LDH@K-NSBC Modified with Magnetic CuFe2O4

Danli Tang,Dengjie Zhong,Yongxian Zhou,Yunlan Xu,Tanxia Xiang,Wantao Li,Yuanfang Yang,Chunmiao Fan,Jisai Chen

In this study, the magnetic composite catalyst, CuFe2O4 modified Co-Al layered double hydroxide supported by alkali-activated N,S-codoped biochar (CFO/CoAl-LDH@K-NSBC) was developed to activate ozone to degrade methylene blue (MB). The MB degradation efficiency of the CFO/CoAl-LDH@K-NSBC/O3 system was 96.30% in 7 min, and it still remained at 92.85% after 5 cycles. Notably, in the pond water matrix, the degradation efficiency only decreased by 6.44% after five cycles, which confirmed its remarkable stability and application prospects. Electrochemical analysis revealed that the comodification of CFO and CoAl-LDH significantly enhanced the charge transfer and catalytic activity of K-NSBC. The results of material characterization and quenching experiments showed that highly exposed active sites, including oxygen vacancies (Ov), Co3+/Co2+, Fe3+/Fe2+, Cu2+/Cu+, pyridinic N, graphitic N and thiophenic S, synergistically drove O3 activation to generate 1O2, ·OH, and ·O2– to participate in MB degradation, among which 1O2 was the main reactive oxygen species. This study provides a novel approach for the preparation of environmentally friendly biochar-based multimetal oxides with high catalytic activity.

Insights into the dehydrogenation reaction process of a K-containing Mg(NH2)2–2LiH system

Yongfeng Liu,Yaxiong Yang,Xin Zhang,You Li,Mingxia Gao,Hongge Pan

The thermal dehydrogenation process of the KOH-containing Mg(NH2)2–2LiH system was systematically investigated by identifying changes in the structure and composition of its components by XRD and FTIR. During ball milling, the added KOH reacts with Mg(NH2)2 and LiH to produce MgO, KH and Li2K(NH2)3. During the initial heating process (<120 °C), the newly formed KH and Li2K(NH2)3 react with Mg(NH2)2 and LiH to yield MgNH, LiNH2 and Li3K(NH2)4 along with hydrogen release. Raising the temperature to 185 °C results in a reaction between Mg(NH2)2, MgNH and LiH that gives Li2Mg2N3H3 as the product and further releases hydrogen. As the temperature is increased to 220 °C, Li2Mg2N3H3 reacts with LiNH2 and LiH to produce Li2MgN2H2 and H2. Meanwhile, two parallel reactions between Li2Mg2N3H3, Li3K(NH2)4 and LiH also generate additional hydrogen. Specifically, the KH and Li2K(NH2)3, formed in situ during ball milling, serve as reactants in the dehydrogenation reaction of the Mg(NH2)2–2LiH system, which is responsible for the significantly improved thermodynamics and kinetics of hydrogen storage.

K-promoted Pt/meso-Al2O3 catalysts for H2 production from dehydrogenation of dodecahydro‑N‑ethylcarbazole

Jihui Yao,Lijuan Su,Lipeng Guo,Xing Wu,Haibo Zhu

N -ethylcarbazole, as a liquid organic hydrogen carrier, has shown great promise in the field of hydrogen storage technology. The development of efficient and stable catalyst for producing H 2 through N -ethylcarbazole dehydrogenation is crucial for its practical application. In this study, a series of mesoporous Al 2 O 3 -supported Pt catalysts with K modification were developed for N -ethylcarbazole dehydrogenation. These catalysts were characterization using various techniques including XRD, N 2 adsorption–desorption, TEM, 27 Al MAS NMR, XPS, NH 3 -TPD, H 2 -TPR, CO-FTIR, and Py-IR, providing detailed structural information to elucidate the structure–activity relationship. Mesoporous Al 2 O 3 was found to possess significant amounts of coordinatively unsaturated pentacoordinate Al 3+ , which greatly promotes the dispersion of Pt species for the formation of small Pt particles. The addition of K was observed to modulate the electronic structure of Pt, reduce the acidity of the catalysts, and inhibit the sintering of Pt. These synergetic effects led to Pt 3.0 /K 3.0 -Al 2 O 3 -m achieving remarkable performance in dodecahydro- N -ethylcarbazole dehydrogenation at 180 °C and 101 kPa, delivering a dodecahydro- N -ethylcarbazole conversion of 100 %, H 2 release amount of 5.63 wt% and dehydrogenation efficiency of 97.10 %. Additionally, this catalyst demonstrated high efficiency in the dehydrogenation of dodecahydro- N -propylcarbazole, octahydro-2-methylindole, and octahydro-1,2-dimethylindole, achieving dehydrogenation efficiencies of 99.60 %, 100 % and 100 %, respectively. These findings provide valuable knowledge for the rational design of efficient metal-based catalysts for liquid organic hydrogen carriers in hydrogen storage systems.