APPLIED CLAY SCIENCE
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2018
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IF 3.641
Zhu Chen,Jingrong Li,Zhen Cheng,Shufeng Zuo
In the study, the effects of synthesis conditions for AlNi composite pillaring agents (Al/Ni molar ratio, aging temperature and aging time) on the structure and stability of AlNi pillared clays (AlNi-PILC) were investigated. And the results showed that the above synthesis factors could control and adjust the specific surface area, pore volume and basal spacing of AlNi-PILC. The formation of spinal NiAl 2 O 4 markedly improved the thermal stability and anti-sintering properties of AlNi-PILC and maintain a stable mesoporous structure. Pd/AlNi-PILC nanocrystalline catalyst obtained by using a high-temperature solution-phase reduction method presented a strong interaction between the active species PdO x (x = 0, 1) and AlNi-PILC. The PdO x nanocrystals had excellent stability with a small diameter (1–2 nm) and the nanocrystals were evenly mono dispersed on the surface of AlNi-PILC. Thus, 0.2%Pd/AlNi-PILC exhibited excellent catalytic oxidation properties and completed catalytically oxidize low concentrations of benzene at 250 °C. Furthermore, 0.2%Pd/AlNi-PILC maintained 90% benzene conversion at 240 °C after a continuous reaction for 1000 h in dry air. And in either wet conditions or in the chlorine-containing VOCs, 0.2%Pd/AlNi-PILC maintained high catalytic activity and thus showed potential in industrial applications.
研究领域:
环境催化
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材料化学
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纳米催化
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大气污染控制
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多相催化
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
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2024
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IF 3.3
Tao Wang,Benlong Yu,Long Mu,Zhilin Chen,Chao Xiao,Shuming Peng
The palladium oxide phase (PdOx) plays a critical role in catalytic methane oxidation and CO oxidation reactions. Precise characterization of supported PdOx by CO-FTIR spectroscopy is often accompanied by the reduction of PdOx by CO. Lowering the CO partial pressure to 0.05% CO/N2 (0.5 mbar) and the adsorption temperature to −130 °C is a proper condition to inhibit the reduction completely. Then CO-FTIR spectroscopy was conducted on a series of supported PdOx catalysts. We find that CO adsorbed on coordinatively unsaturated Pd atoms (Pdcus) on the PdOx surface gives three adsorption bands at ∼2145 cm–1. Three types of surface Pdcus atoms with different degrees of coordination unsaturation (types I, II, and III) exist in supported PdOx catalysts; their νCO are located at 2133, 2145, and 2160 cm–1, respectively. The order of coordination unsaturation of surface Pdcus should be type III < type II < type I. Since νCO of surface Pdcus is between νCO of Pd2+(CO) and Pd+(CO), the effective charge of surface Pdcus is 1 < n < 2. For small PdOx clusters in zeolite-supported PdOx catalysts, surface Pdcus atoms with more coordination unsaturation (i.e., step, edge, and corner sites) are more abundant, leading to greater IR intensity of adsorbed CO.
研究领域:
催化化学
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表面化学
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光谱学
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材料科学
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环境化学
✓ 已验证
DOI
高影响因子
ACS Catalysis
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2025
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IF 13.1
Tao Wang,Qiao Yu,Zhilin Chen,Chao Xiao,Shuming Peng
The active phase for methane combustion is still in debate. Low-temperature CO-FTIR spectroscopy was used to probe the working surface state on a series of Pd/Al2O3 (PdAl) and Pd/silicalite-1 (PdSil) catalysts with different starting states: oxidized, reduced (R), reoxidized (Ro). The surface of prereduced PdAl (Pd0) is transformed to an oxidized state (PdOx) with a CO stretching vibration (νCO) at ∼2157 cm–1 when it is aged in the methane oxidation mixture. The aging-induced transformation from Pd0 to PdOx occurred at 250 °C or above. Although PdSil has multiple kinds of PdOx entities, prereduced PdSil also transformed into PdOx. For PdAl(4)-R-A250, XRD patterns suggest weak bulk oxidation of Pd0 at 250 °C, XPS spectra indicate 28% of surface Pd0 atoms are oxidized, but CO-FTIR spectra confirm all the “top surface” Pd0 atoms are oxidized. It demonstrates the advantage of CO-FTIR spectroscopy in probing the top surface state. Finally, a direct correlation between operando FTIR spectroscopy and low-temperature CO-FTIR spectroscopy was established. Operando FTIR spectra over PdSil during methane oxidation at 250 °C gives two bands at 2124 cm–1 (CO–Pd+) and 2161 cm–1 (CO–Pd2+). After cooling in nitrogen, CO-FTIR spectra give two similar bands at 2134 cm–1 and 2157 cm–1. The “working surface state” can be preserved in CO-FTIR. For PdAl(4), operando FTIR spectra at 250 and 300 °C give no bands of adsorbed CO. Adding CO into the methane oxidation mixture resulted in a single CO–Pd2+ band at 2163 cm–1, which is in accord with their CO-FTIR spectra. For operando FTIR spectroscopy, the observation of the bands of adsorbed CO depends on the accumulation of the CO intermediates, but their accumulation is limited to reaction temperatures below 300 °C and to PdSil (not PdAl). These limitations make low-temperature CO-FTIR spectroscopy more general and sensitive.
研究领域:
催化化学
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材料科学
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环境化学
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光谱学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
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IF 3.99
Xiaoying Lu,Qian Yu,Xueqin Tao,Ting Wang,Kun Zhang,Benxia Li
Pd-based catalysts with high activity and recoverability are desirable for Suzuki coupling reactions which represent an important strategy for constructing carbon-carbon bonds in organic synthesis. Herein, a magnetic PdO x /NiFe 2 O 4 NFs catalyst consisting of PdO x nanoparticles (NPs) and NiFe 2 O 4 nanofibers (NFs) is synthesized by an electrospinning-calcination process. The microstructures and chemical compositions of PdO x /NiFe 2 O 4 NFs catalyst are well characterized. The optimized PdO x /NiFe 2 O 4 NFs exhibits high catalysis toward Suzuki coupling reactions under mild conditions, benefiting from the special electronic state of Pd δ+ (0 < δ < 2) active sites and the porous nanofiber structure of NiFe 2 O 4 support. The turnover frequencies (TOFs) for the reactions of iodo-, bromo- and chloro-benzene over the PdO x /NiFe 2 O 4 NFs catalyst reach up to 2064.79, 1366.74 and 215.28 h −1 , respectively, far exceeding those over the commercial Pd/C catalyst. The kinetic studies demonstrate that the PdO x /NiFe 2 O 4 NFs catalyst is more efficient to reduce the activation energy of Suzuki coupling reaction, which can be attributed to the superiority of Pd δ+ species in both charge-donating and charge-accepting steps of the reactions. Moreover, the PdO x /NiFe 2 O 4 NFs catalyst can be facilely separated and recycled in a long-term catalytic reaction owing to its distinct magnetic feature and good structural stability. This work affords a facile approach for the synthesis of heterogeneous catalyst with tunable compositions and porous structures as well as an attractive catalyst with superior catalytic activity, high stability and reusability.
研究领域:
化学
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材料科学
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有机合成
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
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2020
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IF 4.189
Ting Wang,Xueqin Tao,Donghai Wu,Xiaoying Lu,Qian Yu,Shoujie Liu,Houyang Chen,Benxia Li
Heterogeneous Pd-based catalysts are receiving great attention in cross-coupling reactions due to their distinct advantages of relatively low cost, high stability, easy separation, and recycling. Nonetheless, great challenges still remain in developing heterogeneous catalysts with excellent performance and revealing the origin for efficient catalysis. Herein, we have synthesized a PdOx/NiO NFs catalyst consisting of porous NiO nanofibers and in situ anchored PdOx species by a facile electrospinning–pyrolysis strategy. The electron transfer from NiO to PdO created during the calcination step results in the formation of Pdδ+ (δ < 2) in the PdOx/NiO NFs, validated by both spectroscopic analyses and computational modeling. The PdOx/NiO NFs catalyst exhibits much higher activity than the commercial 5.0 wt % Pd/C and other as-prepared Pd-based catalysts in Suzuki coupling reactions. The turnover frequency (TOF) values for the conversions of iodo-, bromo-, and chlorobenzenes over the PdOx/NiO NFs catalyst are 6.6–7.3 times those over the commercial 5 wt % Pd/C catalyst. Theoretical calculations demonstrate that the configuration of PdO(101)/NiO(111) surface is more propitious to the adsorption and activation of arylhalide and phenylboronic acid than that of Pd(111)/NiO(111) surface. The compelling performance of PdOx/NiO NFs is mainly attributed to the special surface configuration of PdOx and unique electronic state of Pdδ+ species. These traits can be well retained in a long-term reaction owing to the strong metal–support interaction, ensuring the good durability of the catalyst. This study not only develops a promising heterogeneous catalyst with high performance for green synthesis of fine chemicals but also provides insights into the enhancement of catalytic activity achieved by modulating the active centers.
研究领域:
催化化学
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材料科学
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理论计算化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2026
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IF 9.2
Ubong J. Etim,Peng Bai,Waheed Iqbal,Ziyi Zhong
Supported palladium (Pd) catalysts are known for their exceptional catalytic activity in methane combustion; however, they often undergo rapid deactivation due to sintering under practical reaction conditions. This study aims to develop highly active and stable catalysts for CH 4 combustion by investigating the effect of guest elements within silicalite-1 (S-1) zeolite as supports for Pd. Various transition metals (TMs) were introduced into the S-1 gel to modify its structural properties. The TMs were incorporated into both framework and extra-framework positions, as demonstrated for iron (Fe) and titanium (Ti), resulting in the formation of FeS-1 and TS-1, respectively. The structures were confirmed by Fourier transform infrared (FTIR) and ultraviolet-visible diffused reflectance (UV-vis DR) spectroscopy. Following Pd impregnation, the resulting Pd/FeS-1 and Pd/TS-1 exhibited high activity in CH 4 combustion. Compared to 1Pd/S-1, both 1Pd/FeS-1 and 1Pd/TS-1 achieved excellent low-temperature catalytic performance (T 90 < 400 °C), along with high reaction rates, turnover frequency (TOF) and stability. Characterization of the catalysts confirms the stabilizing effects of Fe and Ti on Pd species, primarily attributed to the formation of PdO x nanoclusters. Fe 3+ maintained PdO x in a more oxidized state, facilitated the activation of gas-phase oxygen, and provided anchoring sites for CH 4 activation into CH 3 ∗ , which combined with activated oxygen species. The reaction follows the Langmuir-Hinshelwood (L-H) mechanism, in which both CH 4 and oxygen are first adsorbed on the catalyst surface. Adsorbed and activated CH 4 species are sequentially oxidized by active oxygen species, leading to the formation of chemisorbed CO species, which are transformed into CO 2 and H 2 O as the final products.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CONTROLLED RELEASE
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2024
·
IF 10.5
Ke Gong,Jiangtao Lin,Xiaoyan Chen,Yi Duan,Jiali Zhang,Jian Yu,Jing Wang,Ruifang Sun,Jie Li,Yourong Duan
In esophageal cancer (EC), clinical specimen testing has uncovered a significant increase in BTB and CNC homolog 1 (BACH1) expression and a shift towards an immunosuppressive environment, alongside a notable decrease in p53 protein expression. Therefore, therapeutic strategies focusing on BACH1 inhibition and p53 upregulation appear promising. Traditional oral treatments for EC lack precision and efficacy. Here, we propose a novel approach employing tumor-targeted nanoparticles (NPs) for drug delivery. However, the formation of a drug reservoir at the esophageal site, crucial for the sustained release of therapeutics, presents significant challenges in nano-delivery systems for EC treatment. To address this, we developed a thermosensitive hydrogel composed of F127 and tannic acid, serving as a vehicle for NP loading. These NPs, synthesized through the emulsion/volatization methods of mPEG-PLGA-PLL-cRGD, facilitate in situ drug delivery. Upon contacting esophageal tissue, the hydrogel transitions to a gel, adhering to the lining and enabling sustained release of encapsulated therapeutics. The formulation encompasses NPs laden with small interfering RNA targeting BACH1 (siBACH1) and the p53 activator PRIMA-1, creating a cohesive gel-nano system. Preliminary biological assessments demonstrate that this injectable, thermosensitive gel-nano system adheres effectively to esophageal tissue and targets EC cells. For better modeling clinical outcomes, a patient-derived organoid xenograft (PDOX) model was innovated, involving transplantation of EC-derived organoids into humanized mice, reconstructed with peripheral blood mononuclear cells (PBMCs). Post-treatment analysis showed substantial EC growth inhibition (89.51% tumor inhibition rate), significant BACH1 level reduction, restored anti-tumor immune responses, and pronounced tumor apoptosis. In summary, our study introduces a thermosensitive gel-nano system for EC treatment via restoring p53 activity and boosting T-cell immunity, with potential for clinical application.
研究领域:
肿瘤学
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药学
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生物技术
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免疫学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xiaolu Chen,Rongying Ma,Zhaoming Fu,Qianhong Su,Xingyu Luo,Yingchao Han,Yong Yang,Qingchun Deng
Multidrug resistance (MDR) of cancer is the main reason for cancer chemotherapy failure, and the use of anticancer drugs usually brings about adverse side effects to patients. Therefore, the aim of developing new cancer treatments must consider overcoming MDR and abating the toxicity of drugs to normal tissues. In this work, we designed and prepared multifunctional cascade amplification delivery nanoparticles (CADNs) with a core structure composed of glucose oxidase (GOx)-attached Fe 3 O 4 nanoparticles, and a shell layer of PEGylated metal-phenolic networks (MPNs), in which the prodrug of doxorubicin (pDOX) was loaded. In vitro assays showed that the MPNs had dual sensitivities to acidic and reducing conditions, and the CADNs promoted the production of hydroxyl radicals in the presence of H 2 O 2 and glucose. Besides, cellular experiments demonstrated that CADNs could efficiently facilitate the accumulation of pDOX in doxorubicin-resistant MCF-7/Adr cells and enhance cancer cell death under the combined action of ferroptosis and chemotherapy. Furthermore, in vivo assays also showed that CADNs with a PEGylated surface could effectively target tumors, and dramatically suppress the growth of both MCF-7 and MCF-7/Adr tumors, with excellent biosafety. This work presents a novel strategy for overcoming cancer MDR by driving cascade reactions to achieve starvation/chemodynamic/chemo combination therapy.
研究领域:
纳米技术
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药学
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癌症研究
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）