CHINESE JOURNAL OF CATALYSIS
·
2019
·
IF 4.914
Hao Wang,Xiaohao Liu,Guangyue Xu,Ziwei Guo,Ying Zhang
ABSTRACT Owing to Fe being the most abundant and least expensive transition metal on the earth, the utilization of Fe-based catalysts for catalytic hydrogenation has attracted worldwide attention. In this work, a series of N-doped C supported Fe catalysts (Fe-N-C) were prepared by co-pyrolysis of cellulose and ferric chloride under ammonia atmosphere. Characterization methods such as elemental analysis, atomic absorption spectroscopy, nitrogen adsorption-desorption isotherms, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out to explore the physicochemical properties of the catalysts. Using hydrogenation of nitrobenzene as a model reaction, the catalysts prepared at different pyrolysis temperatures displayed different activities. Fe-N-C-700 exhibited the best activity among these catalysts, with the yield of aniline being up to 98.0% under 5 MPa H 2 at 120 °C after 12 h. Combined with the results of catalyst characterization and comparative tests, the transformation of Fe species and the generation of N-doped C, especially graphitized N-doped C, in the catalyst may be the main factors affecting the activity. A kinetic study was carried out and the apparent activation energy was obtained as 31.53 kJ/mol. The stability of the catalyst was also tested and no significant decrease in the activity was observed after 5 runs.
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2017
·
IF 2.429
Yanran XUN,Xinxin HE,Han YAN,Ziwang GAO,Zhao JIN,Chunjiang JIA
In this paper, a series of Fe- and Co-doped lanthanum (hydr)oxides catalysts were prepared by a simple coprecipitation-hydrothermal method. The as-prepared catalysts were characterized with various techniques including powder X-ray diffraction (XRD), N 2 adsorption/desorption, inductively coupled plasma (ICP) and transmission electron microscopy (TEM). The Fe-based catalysts exhibited consecutive phase changes of amorphous FeO x →FeLaO 3 →Fe 2 N under different stages (as-prepared→calcination→ammonia decomposition reaction); as for Co-based catalysts, the phase transformation followed a sequence of Co(OH) 2 → Co 3 O 4 →metallic Co. It was revealed that Fe 2 N and metallic Co were most probably the active crystalline phase respectively for Fe- and Co-based catalysts in the decomposition of ammonia.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2020
·
IF 6.146
Pan Li,Sajjad Hussain,Lu Li,Lingju Guo,Tao He
Band engineering based on the construction of solid solutions is an effective approach to enhance the efficiency of semiconductor photocatalysts, via which the balance between light absorption and driving force can be well achieved by continuously tuning the band structure. Here the ZnS 1– x Se x nanobelt solid solutions have been prepared via thermal treatment of ZnS 1– x Se x (en) 0.5 precursors. The compositions are adjusted by changing the mole ratio of Se to S powder in the starting materials, resulting in continuously modulating the alignment of energy levels of the obtained solid solutions. The band structure is also studied via theoretical calculation. Accordingly, the light harvesting can be tuned too, as confirmed by the UV-vis absorption spectra. XPS valence spectra are used to determine the valence band maximum. Transient photoluminescence spectra are employed to study the separation of photogenerated charge carriers. BET specific surface area and CO 2 adsorption isotherms of different catalysts are measured. The obtained ZnS 1– x Se x nanobelts exhibit different photocatalytic activity for solar-fuel production, dependent on many factors like the light harvesting and alignment of energy levels. The related mechanism is studied in detail.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2020
·
IF 6.146
Xiaona Liu,Yi Cao,Nana Yan,Chao Ma,Lei Cao,Peng Guo,Peng Tian,Zhongmin Liu
The high-temperature (HT) and low-temperature (LT) hydrothermal stabilities of molecular-sieve-based catalysts are important for the selective catalytic reduction of NO x with ammonia (NH 3 -SCR). In this paper, we report a catalyst, Cu 2+ loading SAPO-17, synthesized using cyclohexylamine (CHA), which is commercially available and inexpensive and is utilized in NH 3 -SCR reduction for the first time. After systematic investigations on the optimization of Si and Cu 2+ contents, it was concluded that Cu-SAPO-17-8.0%-0.22 displays favorable catalytic performance, even after being heated at 353 K for 24 h and at 973 K for 16 h. Moreover, the locations of CHAs, host–guest interaction and the Brönsted acid sites were explored by Rietveld refinement against powder X-ray diffraction data of as-made SAPO-17-8.0%. The refinement results showed that two CHAs exist within one eri cage and that the protonated CHA forms a hydrogen bond with O4, which indicates that the proton bonding with O4 will form the Brönsted acid site after the calcination .
✓ 已验证
DOI
高影响因子
NANOTECHNOLOGY
·
2012
·Vol. 23
·期 9
·095603
·
IF 3.979
Shaochun Tang,Sascha Vongehr,Xiangkang Meng
We report a general one-step route to place nanoparticles (NPs) of different noble metals controllably into interior or surface locations of submicron nanoporous carbon spheres (CSs). In particular, Pd and Au NPs can be easily put either inside or outside of the CSs by selecting these metals' differently charged precursor ions. Employing mixed precursor solutions, the method allows different metals to grow simultaneously yet selectively in the separate locations, thus resulting in composites with a complex layered structure, for example Pd or Au outside and Ag inside, Au or Pt outside and Pd inside, and other combinations. The synthesis is fast and needs no additional steps like a functionalization of surfaces. It crucially involves microwave heating, the power setting of which further influences the locations and sizes of the NPs especially in the interior of the amorphous carbon matrix. The three-dimensional composite structures are analyzed by transmission electron microscopy and energy dispersed x-ray spectroscopy combined with quantitative analysis by comparison with simulation. The UV–visible absorption of monometallic and layered composites is compared. The involved mechanisms leading to the selective decoration are discussed; important aspects being the charge of the precursor ions and selective microwave absorption.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2022
·
IF 12.92
Wei Xiong,Min Zhou,Hao Li,Zhao Ding,Da Zhang,Yaokang Lv
ABSTRACT Owing to its cost-effectiveness and adjustable eight-electron distribution in the 3 d orbital, nickel oxide (NiO) is considered an effective electrocatalyst for an ambient electrochemical nitrogen reduction reaction (NRR). However, because of the low conductivity of the transition metal oxide electrocatalyst, its application in this field is limited. In this study, we found that the doping of NiO nanosheets with a small amount (3–10 nm) of Pt nanoparticles (Pt/NiO-NSs) leads to considerable improvements in the Faradaic efficiency (FE) and NH 3 yield compared with those obtained using pure NiO, breaking the common perception that commercial Pt-based electrocatalysts demonstrate little potential for NRR due to their high hydrogen evolution tendency. In a 0.1 mol/L Na 2 SO 4 solution at −0.2 V vs. RHE, a typical Pt/NiO-2 sample exhibits an optimum electrochemical NH 3 yield of 20.59 μg h –1 mg –1 cat. and an FE of 15.56%, which are approximately 5 and 3 times greater, respectively, than those of pure NiO nanosheets at the same applied potential. X-ray photoelectron spectroscopy analysis revealed that Pt in Pt/NiO-NSs exist as Pt 0 , Pt 2+ , and Pt 4+ and that high-valence Pt ions are more electropositive, thereby favoring chemisorption and the activation of N 2 molecules. Density function theory calculations showed that the d -band of Pt nanoparticles supported on NiO is significantly tuned compared to that of pure Pt, affording a more favorable electronic structure for NRR. The results of this study show that Pt can be an effective NRR electrochemical catalyst when loaded on an appropriate substrate. Most importantly, it provides a new synthetic avenue for the fabrication of highly active Pt-based NRR electrocatalysts.
✓ 已验证
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Bin Chen,Jun Ma,Lin Gu,Shuan Liu,Haichao Zhao,Haibin Yu,Jianmin Chen
Electro-active maleic acid capped trianiline (MTA) was synthesized by reaction of maleic anhydride with trianiline (TA). Photopolymerization of aromatic acrylate (PAA) and MTA were applied on Q235 carbon steel to afford oligoaniline containing electroactive coatings. The anticorrosion behavior of photo-cured coatings with 1 wt% and 2.5 wt% MAT was investigated in 3.5% NaCl solution via potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). It was observed that acrylate containing MTA coatings exhibited better corrosion resistance than the pure aromatic acrylate coating did.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2025
·
IF 17.7
Zhenghao Mao,Wenjing Xu,Na Han,Yanguang Li
Aldehydes are valuable intermediates with widespread industrial applications, and their traditional synthesis relies on chemical oxidation that is often hazardous and environmentally unfriendly. Electrochemical oxidation offers a more sustainable and milder alternative; however, it faces challenges such as aldehyde overoxidation and susceptibility to base-catalyzed Cannizzaro disproportionation. Electrochemical glycerol oxidation to glyceraldehyde is a representative example, which typically requires precious metal-based electrocatalysts but still suffers from low selectivity and activity. Here, we report a metal-free oxidation strategy mediated by 2,2,6,6-tetramethylpiperidine-1-oxyl. By systematically investigating the redox thermodynamics and kinetics of TEMPO across a broad pH range, we construct a Pourbaix diagram and elucidate the relative kinetics of each reaction step. These insights allow us to explain the anomalously high apparent Faradaic efficiency (~200%) observed under acidic conditions, and identify neutral media as the optimal environment for selective glyceraldehyde production. Under optimized conditions, our system achieves a glyceraldehyde Faradaic efficiency exceeding 93% and a partial current density of 23.3 mA cm –2 at 0.57 V — more than doubling the performance of the best reported precious metal-based systems. Furthermore, the versatility of this strategy extends to the selective oxidation of other primary alcohols to their corresponding aldehydes with near-unity selectivity.
✓ 已验证
产品关联
DOI
高影响因子
Chinese Journal of Natural Medicines
·
2014
·
IF 0
De-Biao YAN,Dong-Ping ZHANG,Ming LI,Wen-Yuan LIU,Feng FENG,Bin DI,Qing-Long GUO,Ning XIE
To synthesize a series of 3-, 4-, and/or 11-trihydroxy modified bergenin derivatives and evaluated their cytotoxic activity in vitro . The phenolic hydroxyl groups of bergenin were protected by benzyl groups with benzyl bromide. Treatment of dibenzyl bergenin with the corresponding acid in the presence of EDC·HCl and DMAP in CH 2 Cl 2 , followed by hydrogenation over Pd/C catalysts, afforded derivatives of bergenin esters. All of the target compounds were identified by IR, MS, and 1 H NMR. Twenty-six novel and three known derivatives of bergenin esters were synthesized. Their cytotoxicity values were evaluated by the MTT assay on the inhibition of DU-145 and BGC-823 cells in vitro . Several triply-substituted ( 3a, 4a, 5a, 6a, 7a ) and doubly-substituted ( 8b, 9b ) bergenin derivatives exhibited higher cytotoxic activity than bergenin. The result showed that the size of substituents and the lipophilicity of the bergenin esters displayed an important role on their cytotoxic activity.
✓ 已验证
DOI
PubMed
CHINESE JOURNAL OF CATALYSIS
·
2013
·
IF 1.304
Fuhai YU,Junhu WANG,Kunfeng ZHAO,Jie YIN,Changzi JIN,Xin LIU
A series of novel TiO 2 nanocomposite crystals with superior visible-light-driven photocatalytic activity were successfully prepared using a soft chemical solution process involving direct reaction of aqueous H 2 O 2 with a 2-ethoxyethanol solution of tetraisopropyl titanate before calcination of the resulting peroxo-titanium complexes at 500 °C for 4 h. The synthesized TiO 2 samples are composed of anatase and rutile phases , and the ratio of rutile could be continuously tuned from 0 to 96% by altering the 2-ethoxyethanol volume. There are clear red-shifts in the UV-Vis absorption spectra and apparent band gap narrowing for the synthesized TiO 2 in comparison with Evonik P-25. The synthesized TiO 2 samples are found to be much more efficient for methylene blue degradation under visible-light irradiation. The optimized sample (2-ethoxyethanol: 5 ml; rutile in bulk: 46%) exhibits 5-fold higher adsorption capacity and 3-fold higher photocatalytic activity than those of Evonik P-25 (λ ≥ 400 nm). Characterizations including X-ray diffraction and Raman spectroscopy reveal that the surface of the optimized TiO 2 sample only contains a small quantity of rutile. It is concluded that the surface phase composition and distribution of the TiO 2 nanocomposite crystals are essential to their greatly enhanced photocatalytic activities and strong adsorption capacities. In addition, the concentration of defects existing in the synthesized TiO 2 is also regarded to account for these enhanced properties. 摘要 采用新的化学溶液法, 通过不同体积的钛酸四异丙酯的2-乙二醇单乙醚溶液与一定浓度的H 2 O 2 水溶液直接反应并对生成的钛过氧化配合物进行焙烧, 制备了一系列TiO 2 光催化剂. 表征发现, 所得TiO 2 样品为金红石和锐钛矿的纳米复合晶体, 改变2-乙二醇单乙醚的体积可实现金红石相比例在0–96%广范围的调变.与商业二氧化钛P-25相比, 所得的TiO 2 紫外-可见光吸收谱出现明显红移, 间隙能降低, 在可见光照射下, 该样品对亚甲基蓝有良好的降解活性. 当2-乙二醇单乙醚的添加量为5 ml时, 所得样品体相中金红石相比例接近50%, 其光催化活性和吸附性能最好, 可分别是P-25的3倍和5倍. 拉曼光谱结合X射线衍射等表征结果表明, 该样品的表面仅含少量的金红石相. TiO 2 纳米复合晶表面晶相的组成和分布对其光催化降解亚甲基蓝的活性及其吸附能力有直接的影响. 另外, TiO 2 纳米复合晶的缺陷浓度也是增强其光吸收能力, 提高其可见光光催化活性的原因之一.
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2017
·
IF 2.813
Honggen Peng,Jiawei Ying,Jingyan Zhang,Xianhua Zhang,Cheng Peng,Cheng Rao,Wenming Liu,Ning Zhang,Xiang Wang
Catalytic oxidation of formaldehyde (HCHO) is the most efficient way to purify indoor air of HCHO pollutant. This work investigated rare earth La-doped Pt/TiO 2 for low concentration HCHO oxidation at room temperature . La-doped Pt/TiO 2 had a dramatically promoted catalytic performance for HCHO oxidation. The reasons for the La promotion effect were investigated by N 2 adsorption, X-ray diffraction, CO chemisorption , X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and high-angle annular dark field scanning TEM . The Pt nanoparticle size was reduced to 1.7 nm from 2.2 nm after modification by La, which led to higher Pt dispersion, more exposed active sites and enhanced metal-support interaction. Thus a superior activity for indoor low concentration HCHO oxidation was obtained. Moreover, the La-doped TiO 2 can be wash-coated on a cordierite monolith so that very low amounts of Pt (0.01 wt%) can be used. The catalyst was evaluated in a simulated indoor HCHO elimination environment and displayed high purifying efficiency and stability. It can be potentially used as a commercial catalyst for indoor HCHO elimination.
✓ 已验证
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2024
·
IF 4.7
Jia ZHAO,Yi-hang YAN,Hao ZHANG,Hua-yang GAO,Ye ZHANG,Gui-min LU
ABSTRACT The electrochemical behavior of MgCl 2 and the co-deposition mechanisms of Mg and Sr in the SrCl 2 −KCl eutectic system were evaluated using various electrochemical techniques, including cyclic voltammetry (CV), square wave voltammetry (SWV), and open-circuit potential (OCP) analysis. It was observed the Mg(II) reduction on the tungsten electrode in SrCl 2 −KCl melt occurred in a single-step process involving the transfer of two electrons, exhibiting a quasi-reversible mode. The electrochemical co-deposition of Mg and Sr in the SrCl 2 −KCl−MgCl 2 melt involved the formation of two types of Mg−Sr intermetallic compounds. The evolution in the co-deposition mechanism of the nucleation type with changing overpotential was explored through chronoamperometry (CA). It is shown that the nucleation pattern on the electrode surface was depended on the substrate materials and the electrode reaction products. Early-stage nucleation was attributed to Mg(II) reduction under all overpotential conditions. With the co-deposition of Mg and Sr, Mg(II) was reduced to form the Mg nucleus on the electrode surface, followed by underpotential deposition of Sr(II) on the Mg surface accompanied by Mg deposition simultaneously. Additionally, increasing MgCl 2 concentration in the SrCl 2 −KCl melt resulted in a higher current density during the Mg−Sr co-deposition process.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）