LANGMUIR
·
2026
·
IF 3.9
Jingyun Zhao,Qian Lin,Yongyong Shi,Keliang Wang,Hongyan Pan
The direct synthesis of H2O2 from H2 and O2 is a sustainable alternative to the anthraquinone process, but its selectivity is severely limited by competing side reactions together with H2O2 hydrogenation and decomposition, while catalyst degradation and Pd leaching during operation further aggravate the loss of selectivity. In this study, we address these challenges by developing KBr-modified hollow core–shell Pd catalysts. The catalysts were synthesized with controlled KBr incorporation and subjected to thermal treatment to stabilize their electronic structure. Comparative catalytic tests, combined with electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction, and elemental analysis, revealed that KBr modification combined with thermal treatment helps maintain the stability of Pd2+ species, preventing their reduction during catalyst preparation and reaction, while also suppressing Pd leaching. Meanwhile, the hollow core–shell architecture physically confines Pd nanoparticles and minimizes detachment. As a result, the modified catalysts exhibited significantly improved selectivity and long-term cycling stability. These findings demonstrate that halide modification enhances catalyst performance not through simple site poisoning but via electronic modulation and structural stabilization, providing a new strategy for designing selective and durable catalysts for direct H2O2 synthesis.
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DOI
PubMed
高影响因子
JOURNAL OF SOLUTION CHEMISTRY
·
2025
·Vol. 55
·期 2
·290-305
·
IF 1.3
Cui Rui-Zhi,Nie Guo-Liang,Ren Hong-Bao,Yang Qiu-Ye,Li Wu
Based on mother liquor rich in lithium, strontium and bromine obtained from the brine of underground oil–gas field in Qaidam Basin after pre-treatment, the isothermal dissolution equilibrium method was used to study the stable solid–liquid equilibria and phase diagrams of the quinary system LiBr − NaBr − KBr − SrBr 2 − H 2 O and its subsystems at 298.15 K. The solubilities of solids in each system were determined, respectively, and the equilibrium solid phases were determined. In order to clearly reflect the regularities and characteristics of phase equilibria of multi-component systems, the corresponding phase diagrams were also plotted and analyzed. The Pitzer model for the quinary system was parameterized by using relevant experimental thermodynamic data. The solubilities of solids in this quinary system and its subsystems were calculated and compared with experimental results. The results not only help to reveal the thermodynamic behavior of relevant bromides in the process of brine concentration, but also provide some theoretical support for the comprehensive utilization of its brine resources.
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2018
·
IF 4.513
Dan Li,Lingzong Meng,Tianlong Deng,Yafei Guo,Yu Pan
The solubilities and refractive indices of the NaBr–SrBr 2 –H 2 O and KBr–SrBr 2 –H 2 O systems at 288.15 K were investigated with the isothermal dissolution method. The phase diagrams and refractive index diagrams were plotted for the two systems at 288.15 K. The phase diagrams consist of one two-salt cosaturated invariant point , two univariant solubility isotherms, and two stable crystallization fields. The two systems belong to the simple eutectic type, and neither double salt nor solid solution was found. The refractive indices change regularly with the strontium bromide concentration increasing in solution, and reach the maximum value at the eutectic point. On the basis of Pitzer and Harvie-Weare (HW) model, the binary and mixing Pitzer parameters and solubility equilibrium constants of equilibrium solid salts for the two ternary systems at 288.15 K were acquired. And then, the solubilities for the ternary systems at 288.15 K were demonstrated. A comparison shows that the calculated solubilities agree well with the experimental data.
研究领域:
化学热力学
·
溶液化学
·
相平衡
·
无机化学
·
热力学建模
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yapeng Tian,Chenhui Yang,Yi Tang,Yangyang Luo,Xiaojie Lou,Wenxiu Que
Supercapacitors with an advanced high volumetric energy density require a match of both electrodes materials and suitable electrolyte. Here, aqueous asymmetric supercapacitors are designed by employing layered Ti 3 C 2 T x as negative electrodes and highly compact activated carbon (AC) as positive electrodes. Ti 3 C 2 T x //AC asymmetric supercapacitors (Ti 3 C 2 T x //AC ASCs) with 1.7 V voltage window are designed by regulating the mass ratio of both electrodes, which results from the shift of the open circuit potential with different applied voltages. Then, dual-ion hybrid supercapacitors (Ti 3 C 2 T x //AC-KBr HSCs) are also constructed by introducing redox active (KBr) into traditional electrolyte (H 2 SO 4 ) for Ti 3 C 2 T x //AC ASCs to achieve a high volumetric energy density, in which fast hydronium ion intercalated pseudocapacitance happens at the Ti 3 C 2 T x negative electrode, while redox reaction of Br − /Br 3 − within the highly compact AC happens at the positive electrode. As a result, the Ti 3 C 2 T x //AC-KBr HSC achieves a high volumetric capacitance of 250 F cm −3 at 2 mV s −1 , a volumetric energy density of as high as 102.8 Wh L −1 at 424 W L −1 and an outstanding cycling stability with 122% capacitance retention after 6000 cycles. Furthermore, the self-discharge performance for the Ti 3 C 2 T x //AC-KBr HSC is obviously improved, which is mainly ascribed to the adsorption of oxidized species at the AC surface.
研究领域:
材料科学
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电化学
·
能源存储
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DOI
高影响因子
ACS Applied Nano Materials
·
2019
·
IF 0
Shuo Li,Jiawei Liu,Guilin Zhu,Heyou Han
Conformal deposition of Pt-dots arrays on polyhedral Pd nanocrystals can enhance Pt catalytic properties and reduce its loading. Herein, a simple method for the fabrication of Pd@Pt core–shell nanodot arrays (Pd@PtNAs) heterostructures via reducing H2PtCl6 and Na2PdCl4 by l-ascorbic acid in an aqueous solution with cetylpyridinium chloride and KBr is reported. The Pt nanodots arrays with a small size (about 3 nm in diameter) were dispersed on the surface of Pd decahedra. Such ultrasmall size Pt dots arrays can effectively increase the proportion of low-coordination Pt atoms. Compared with commercially available Pt/C catalysts, the Pd@PtNAs show obvious improvement in catalytic performance applied to oxygen reduction reaction. The mass activity (0.20 A/mgPt) of the obtained Pd@PtNAs with 36.9 wt % Pt shows 2.2 times relative to Pt/C catalyst (0.09 A/mgPt) for ORR. What’s more, the Pd@PtNAs with 36.9 wt % Pt exhibited highly stable property and mass activity with only 11% loss after 10 000 testing cycle.
研究领域:
材料科学
·
电化学
·
催化
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DOI
Catalysis Science & Technology
·
2017
·Vol. 7
·期 6
·1415-1422
·
IF 5.773
Zheng Chen,Hongyan Pan,Qian Lin,Xin Zhang,Sheng Xiao,Shun He
Pd core–silica shell catalysts (PdX@SiO2, X = KBr, CTAB, SC) were prepared with and without the addition of three different functional molecules, potassium bromide (KBr), cetyltrimethyl ammonium bromide (CTAB) and sodium citrate dihydrate (SC), by the reverse micelle method, and then characterized by TEM, XRD, EDS, XPS and N2 adsorption/desorption. Results showed that the addition of functional molecules decreased the Pd particle size of the catalysts, and Br− of KBr and CTAB were selectively adsorbed on the surface of Pd particles. Among the prepared catalysts, the catalyst PdKBr@SiO2 had the highest H2O2 selectivity (98%) and productivity (716 mmol gPd−1 h−1). Compared with the catalyst Pd@SiO2 prepared without any additional functional molecules, whose H2O2 selectivity and productivity were 26% and 396 mmol gPd−1 h−1, respectively, the H2O2 selectivity and productivity of the catalyst PdKBr@SiO2 were 277% and 81% higher, respectively, than those of the catalyst Pd@SiO2. The reason for this was that the Br− of KBr can be easily selectively adsorbed on the coordinatively unsaturated sites of the Pd particle surface, which could decrease the energy of the Pd surface and restrain side reactions by inhibiting the O–O bond cleavage of O2 and H2O2. And the catalyst PdKBr@SiO2 has better stability and recyclability than the conventional supported catalyst Pd/SiO2. In contrast, the catalyst PdSC@SiO2 had the lowest H2O2 selectivity (23%) and productivity (395 mmol gPd−1 h−1) because the catalyst PdSC@SiO2 prepared with the functional molecule SC and without Br− had the smallest Pd particle size, which can lead to more coordinatively unsaturated sites and increase side reactions.
研究领域:
催化化学
·
材料科学
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DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2023
·
IF 2.6
Chun-Tao Hu,Yun-Yun Gao,Shi-Hua Sang,Yu-Qiu Cen,Xiao-Feng Guo,Cheng Li
To efficiently exploit and utilize bromine-rich brine resources of China, solid–liquid phase equilibria of the quinary system NaBr–KBr–MgBr2–SrBr2–H2O (saturated with KBr) and the quaternary system NaBr–MgBr2–SrBr2–H2O at 308.2 K were studied in detail by the isothermal dissolution equilibrium method. The dry salt phase diagram of the quinary system NaBr–KBr–MgBr2–SrBr2–H2O (saturated with KBr) includes one invariant point, three isothermal dissolution curves, and three crystallization regions (NaBr·2H2O, KBr·MgBr2·6H2O, and SrBr2·6H2O) under the condition of KBr saturation. And the crystallization region of KBr·MgBr2·6H2O is the smallest, so KBr·MgBr2·6H2O is difficult to crystallize and precipitate. Similarly, The dry salt phase diagram of the quaternary system NaBr–MgBr2–SrBr2–H2O is composed of two invariant points, five isothermal solubility curves, and four crystallization fields, which are hydrate salts NaBr·2H2O, MgBr2·6H2O, and SrBr2·6H2O and anhydrous simple salt NaBr. The crystallization region of MgBr2·6H2O is the smallest, the solubility of magnesium bromide is the largest, and it is difficult to crystallize and precipitate in this saturated solution. Furthermore, the mixing ion-interaction parameter ΨNa, Sr, Br of Pitzer’s model is fitted, which can be used for the subsequent prediction of phase equilibria containing strontium system. In addition, the solubilities of salts in the quinary system and the quaternary subsystem were theoretically predicted, and the experimental value was compared with the calculated value. The calculated value was in good agreement with the experimental value.
研究领域:
化学工程
·
无机化学
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高影响因子
危险品化学品经营许可证（带存储）