Molecular Catalysis
·
2020
·
IF 3.687
Ning Xiang,Xiaojin Han,Yarong Bai,Qiaoyan Li,Jianfeng Zheng,Yulin Li,Yaqin Hou,Zhanggen Huang
Supported noble metal catalysts have been widely utilized for HCHO catalytic oxidation. When the active components are fixed, the altering and regulation of the supports would have a huge effect on catalytic performance. Here, two types of Pd/γ-Al 2 O 3 catalysts with different support size (micro-γ-Al 2 O 3 and nano-γ-Al 2 O 3 , respectively) were fabricated and used for HCHO oxidation. Compared with the micro-sized counterpart, the Pd/nano-γ-Al 2 O 3 catalyst exhibited much superior HCHO oxidation performance which could totally oxidize 160 ppm of HCHO into harmless CO 2 under a WHSV of 100,000 mL g cat −1 h −1 at room temperature. Multiple characterizations including XRD, BET, TEM, CO chemisorption, FT-IR, O 2 -TPD, XPS and in situ DRIFTS were implemented to study the effect of γ-Al 2 O 3 support size on physicochemical properties of Pd/γ-Al 2 O 3 catalysts and elucidate the structure-activity relationship. The results revealed that large specific surface area, rich surface OH groups as well as high curvature of nano-γ-Al 2 O 3 not only facilitated HCHO adsorption, but also stabilized highly dispersed Pd species which then promoted the activation of oxygen and boosted formate species decomposition, and consequently leading to the enhanced HCHO oxidation performance of Pd/nano-γ-Al 2 O 3 . This work deepens the comprehension of support size-dependent activity of Pd/γ-Al 2 O 3 catalysts for HCHO oxidation and provides an alternative method to prepare high-performance Pd catalysts for HCHO oxidation.
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Jirui Yang,Xinhua Qi,Feng Shen,Mo Qiu,Richard Lee Smith
Transfer hydrogenation is highly effective for dechlorinating priority organic pollutants in wastewater. Lindane could be completely dechlorinated at room temperature and atmospheric pressure via transfer hydrogenation, in which Pd (3.1 wt%) supported on chitosan-derived porous carbon (3.1Pd@A600) and formic acid (FA) were used as catalyst and hydrogen source, respectively. Favorable catalytic activity of 3.1Pd@A600 is attributed to pyridinic N of the support that allowed Pd nanoparticles to be well-dispersed in the solid and to pyridinic N-Pd interactions that enhanced FA decomposition over that observed for commercial carbon supported Pd catalyst (5Pd@AC). In the reaction system containing 3.1Pd@A600 and FA, 99.7% lindane conversion and 100% dechlorination efficiency could be achieved at 25 °C and atmospheric pressure within 60 min. Benzene and cyclohexane were identified as end-products of lindane dechlorination . The transfer hydrogenation strategy developed in this study has wide application to chlorinated organic pollutants contained in actual waste streams.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biomolecules
·
2020
·Vol. 10
·期 2
·285
·
IF 4.082
Ehexige Ehexige,Mingming Bao,Purevbat Bazarjav,Xiang Yu,Hai Xiao,Shuqin Han,Huricha Baigude
Cutaneous melanoma is the most aggressive skin cancer with notorious drug resistance. Inhibition of immune checkpoint molecules is one of the most promising approaches for cancer therapy. Herein, we show that RNAi mediated silencing of STAT3 expression in the tumor tissue robustly inhibit tumor growth in B16F10 mouse model of melanoma. We designed a peptidomimetic-based lipid nanoparticles (LNPs) for the delivery of siRNA in mouse model of melanoma. When systemically administered, the novel formulation (denote DoCh) preferentially delivered siRNA to the tumor tissue. Remarkably, sequential intravenous injections of siRNA against STAT3 induced profound silencing of STAT3 expression in tumor tissue, which resulted in significant downregulation of PD-L1, leading to significant inhibition of tumor growth through inhibition of tumor immune checkpoint. Moreover, DoCh-mediated siRNA delivery did not show noticeable damage to the major organs. Collectively, our data demonstrated that DoCh LNP is a promising tumor-targeted siRNA delivery system.Keywords:peptidomimetic lipid nanoparticle;RNAi;STAT3;PD-L1;cancer immune checkpoints
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2020
·Vol. 25
·期 11
·2475
·
IF 3.267
Yanliang Yang,Dexi Yang,Chi Zhang,Min Zheng,Ying Duan
The development of a simple and durable catalytic system for the production of chemicals from a high concentration of a substrate is important for biomass conversion. In this manuscript, 5-hydroxymethylfurfural (HMF) was converted to 1-hydroxy-2,5-hexanedione (HHD) using the combination of commercial Pd/C and acetic acid (AcOH) in water. The influence of temperature, H2pressure, reaction time, catalyst amount and the concentration of AcOH and HMF on this transformation was investigated. A 68% yield of HHD was able to be obtained from HMF at a 13.6 wt% aqueous solution with a 98% conversion of HMF. The resinification of intermediates on the catalyst was characterized to be the main reason for the deactivation of Pd/C. The reusability of the used Pd/C was studied to find that most of the activity could be recovered by being washed in hot tetrahydrofuran.Keywords:HMF;1-hydroxy-2,5-hexanedione;acetic acid;Pd/C;high concentration
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Kelin Hu,Feipeng Wang,Zijia Shen,Hongcheng Liu,Jianglin Xiong
In this paper, Pd/ZnO–SnO 2 hollow nanofibers prepared by electrospinning and magnetron sputtering . The sensing materials exhibited extraordinary hydrogen (H 2 ) sensing behavior – the response reached 171 at 270 °C, and besides, the response time and recovery time were as low as 19 s and less than 1 s at 240 °C, with steady high selectivity and good repeatability. Such an enhanced sensing performance could be attributed to the Pd/ZnO/SnO 2 ternary heterojunctions formed in the hollow nanofibers. Moreover, the materials were studied by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and especially the morphology formation process was further explained. The existence of Pd was confirmed to increase the resistance modulation range of heterojunction. In addition, the gas sensing mechanism based on the structure was proposed.
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Wen Li,Kuncan Wang,Guowu Zhan,Jiale Huang,Qingbiao Li
The chemical transformation of CO2 to value-added chemicals and fuels remains a daunting research challenge, requiring the development of more efficient catalysts. The present work offers highly active integrated nanocatalysts for CO2 hydrogenation to dimethyl ether (DME) through tandem catalysis, that is, Pd/ZnO converts CO2 to methanol, and bio-ZSM-5 further catalyzes methanol dehydration to DME. Notably, the hierarchically porous bio-ZSM-5 with high pore connectivity was prepared by using low-cost rice husk and luffa sponge as biotemplates. The formation of bio-ZSM-5 involved three consecutive steps, including (i) diffusion of precursor species, (ii) confined crystal growth, and (iii) calcination treatment to remove the residual biomass. Interestingly, the obtained bio-ZSM-5 possesses abundant hierarchical porosity, including the intrinsic micropores from ZSM-5 frameworks, the mesopores from intracrystalline void space or pinholes in the intergrown zeolite layers, and the macroscopic channels from the original biomass architecture. It was found that the tetrapropylammonium hydroxide amount and Si/Al ratio were two critical factors affecting the crystallinity and porosity of the bio-ZSM-5. The silicon content in biomass (8.3 wt % in rice husk and 0.016 wt % in luffa sponge) also played a crucial role in the synthesis of bio-ZSM-5. Different spatial configurations of Pd/ZnO and bio-ZSM-5 significantly affected the DME yield, wherein spatial distances between the bio-ZSM-5 and Pd/ZnO components were adjusted by controlling the size of Pd/ZnO or the integration manners. The current results indicated that the closest proximity of the bifunctional catalyst was unfavorable for DME production (selectivity < 3%), because of which low-valent Zn cations from Pd/ZnO could displace the Brønsted acid sites on bio-ZSM-5 by ion exchange, and the powder mixing in the mortar was the best combination configuration of Pd/ZnO and bio-ZSM-5, promoting the CO2 conversion (10.8%) with a DME selectivity of 31% under the reaction of 300 °C and 30 bar. Furthermore, as compared to the traditional ZSM-5 based catalyst, the obtained Pd/ZnO/bio-ZSM-5 bifunctional catalysts showed excellent long-term stability in 60 h on stream with a less amount of coke formed in the spent catalysts.
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 47
·18601-18610
·
IF 3.069
Siwen Xia,Yu Yang,Changli Lü
Functionalized two-dimensional graphene oxide sheets and their inorganic–organic nanohybrids have aroused great interest because of their excellent synergetic effect on metal-based nanocatalyst PdNPs supported on highly hydrophilic quaternized polyhedral oligomeric silsesquioxane (QPOSS) functionalized reduced graphene oxide (rGO) and were successfully constructed as a nanohybrid catalyst for efficient heterogeneous catalytic reactions. Octaammonium POSS (OAPOSS) was first covalently grafted to carboxylated GO nanosheets through an amidation reaction, and then the OAPOSS decorated on rGO nanosheets was quaternized with glycidyltrimethylammonium chloride (GDTMAC) via an epoxide ring-opening reaction to obtain a highly functional hydrophilic QPOSS@rGO hybrid. Finally, the PdNPs were loaded onto QPOSS@rGO nanosheets through an in situ reduction route. The quaternary ammonium groups on QPOSS@rGO can strongly coordinate with PdNPs, making it particularly advantageous for stabilizing PdNPs and preventing the leaching of Pd metals. Compared to the PdNPs@rGO catalyst without modification with hydrophilic QPOSS, the low-dose PdNPs@QPOSS@rGO nanocatalysts exhibited outstanding catalytic efficiency in the reduction of methylene blue and nitrophenols. In addition, the as-designed nanocatalysts also showed high catalytic activity for the Suzuki coupling reaction when utilizing pure water as a green solvent. It was proved that QPOSS and rGO can synergistically catalyze and promote the diffusion of reactants. In particular, the PdNPs@QPOSS@rGO nanohybrid catalyst showed no significant loss of catalytic activity after reusing it five times. Our results demonstrated that highly hydrophilic QPOSS endows the resulting PdNPs@QPOSS@rGO nanohybrid with good dispersibility and stability in water, which remarkably further improves the catalytic activity of the nanocatalyst.
✓ 已验证
产品关联
DOI
高影响因子
CARBON
·
2019
·
IF 7.466
Chun Pu,Jie Zhang,Ganggang Chang,Yueyang Xiao,Xiaochen Ma,Jian Wu,Tingting Luo,Kexin Huang,Shanchao Ke,Jiaxin Li,Xiaoyu Yang
Nitrogen-doped carbon-supported metal catalysts are of considerable significance in a diverse range of applications. However, the controllable synthesis of morphology and composition of carbon support materials, in turn, the particle size of supported metal nanoparticles (NPs) is still a great challenge. Herein, nitrogen precursors-mediated synthesis of N-doped hierarchically porous carbon (HPC) with controlled morphology and composition by using MOF as sacrificial template has been demonstrated for the first time. By simply varying the category of nitrogen precursors that with different chemical environment, the morphology, nitrogen configurations and hydrophilicity of the resulted HPC can be effectively tuned. Particularly, the delicate honeycomb-like morphology, the largest amount of nitrogen dopants and excellent wettability of HPC-DCD (dicyandiamide) can effectively stabilize, isolate and disperse the Pd NPs to yield highly dispersed Pd NPs. More importantly, the resulted Pd@HPC-DCD showed excellent catalytic activity and stability toward the hydrodeoxygenation of vanillin in aqueous solution with >99% yield, as well as good universality toward a series of unsaturated hydrocarbons catalyzed by using H 2 or formic acid as hydrogen source in aqueous reaction. Such excellent catalytic performance of Pd@HPC-DCD in aqueous solution can be attributed to the hierarchical structure, well-dispersed Pd sites, as well as the favorable hydrophilicity.
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2019
·Vol. 30
·期 1
·1906623
·
IF 15.621
Wenfei Chen,Zhaofei Guo,Yining Zhu,Nan Qiao,Zhirong Zhang,Xun Sun
Photothermal therapy (PTT) is a promising cancer treatment, but it has so far proven successful only with relatively small subcutaneous tumors in animal models. Treating larger tumors (≈200 mm 3 ) is challenging because most PTT materials do not efficiently reach the hypoxic, avascular center of tumors, and the immunosuppressive tumor microenvironment prevents T cells from fighting against residual tumor cells, thereby allowing recurrence and metastasis. Here, the widely used PTT material polydopamine is coated on the surface of the facultative anaerobe Salmonella VNP20009, which can penetrate deep into larger tumors. The coated bacteria are intravenously injected followed by near-infrared laser irradiation at the tumor site, combined with a local inoculation of phospholipid-based phase separation gel containing the anti-programmed cell death-1 peptide AUNP-12. The gel releases AUNP-12 sustainably during 42 days, maintaining the tumor microenvironment as immunopermissive. Using a mouse model of melanoma, this triple combination of biotherapy, PTT, and sustainable programmed cell death-1 (PD-1) blockade shows high efficiency on eliciting robust antitumor immune responses and eliminating relatively large tumors in 50% of animals within 80 days. Thus, the results shed new light on a previously unrecognized immunological facet of bacteria-mediated therapy, and this innovative triple therapy may be a powerful cancer immunotherapy tool.
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2022
·
IF 3.754
Jingtao Zhang,Mengwan Zhai,Xueying Wang,Shurui Liu,Lijuan Zhang,Xing Liu,Yao Geng,Xiaodong Sun,Bingkun Liu
In the present work, Ti 3+ -self-doped TiO 2 heterostructure photocatalysts were prepared by coupling with different additions of palladium quantum dots by means of deposition-reduction methodology. The electron paramagnetic resonance (EPR) analysis indicated the existence of Ti 3+ in synthesized samples. The transmission electron microscopy (TEM) images presented the modification of TiO 2-x nanoparticles by coupling with nano palladium. Photoluminescence (PL) results demonstrated the lowest charge carrier recombination rate in 5% Pd/TiO 2-x composites. Photocatalytic performances of photocatalysts were evaluated by degrading Tetracycline (TC) and inactivating Escherichia coli ( E. coli ) and Fusarium oxysporum f. sp. Vasinfectum ( Fov ) with the presence of visible light , in which an enhanced photocatalytic degradation and inactivation activity was found in all Pd coupled composites with the highest efficiency in 5% Pd/TiO 2-x . The improved photocatalytic activity of Pd/TiO 2-x was associated to the generation of more hydroxyl radicals (•OH) and superoxide anions radicals (•O 2- ) during photocatalytic process which were demonstrated by the electron spin-resonance spectroscopy (ESR) technique. Moreover, 5% Pd/TiO 2-x composites were found to remain high photocatalytic properties in a circulating photo-disinfection system.
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Defu Yin,Renjie Ji,Jingyun Zhang,Shitao Yu,Lu Li,Shiwei Liu,Long Jiang,Ying Liu,Zhanqian Song,Yue Liu
A core–shell catalyst composed of mCeO 2 shell and Pd metal core was prepared by one-pot wet chemical method and used for the hydrogenation of phenol to cyclohexanone. The phenol conversion and cyclohexanone selectivity were 96.3 % and 95.3 % at reaction conditions of 50 min, 80 °C and 1 MPa H 2 . The effects of Ce species and Br species in the preparation of catalysts was studied, and the synthesis mechanism of core–shell Pd@mCeO 2 catalysts was preliminarily revealed. By discussing the phenol adsorption mechanism and the redox properties of the catalyst, the activation of H 2 by Pd sites and phenol by cerium oxide (CeO 2 ) sites of the surface were studied. H 2 -TPR and XPS characterization were used to explain the effect of Ce species and Br species for the catalytic performance. These results indicated that the electronic structure of Pd was regulated by the interaction between Pd and Ce, and different O sites were generated around the Pd sites. In situ IR spectra indicated that phenol was adsorbed and dissociated on cerium to form phenoxy species and water, this synergistic catalytic pattern of carrier activated substrate and hydrogenation site promoted the hydrogenation of phenol and improved the catalytic efficiency.
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Tianyu Guo,Xiaorong Nie,Jianping Du,Jinping Li
Methane oxidation is a strong exothermal reaction, the heat released from which can be utilized and the greenhouse effect caused by emitted methane, particularly low-concentration methane (LCM), can be further relieved. Presently, one of the key problems is to develop an efficient catalyst material for promoting LCM oxidation. Here, we synthesized an alumina with 2D feather-like lamella structure (FLAO), which is suitable for industrial applications. The samples were characterized by X-ray diffraction, scanning/transmission electron microscopy, X-ray photoelectron spectroscopy and nitrogen adsorption/desorption techniques. The results show that as-synthesized alumina has feather-shaped morphology and 2D slices structures, which form loose framework. Pd nanoparticles were easy to be anchored and well-dispersed on the surface of alumina. The FLAO-supported Pd catalysts exhibited high activity and stability. For 360000 mL g −1 h −1 space velocity, the LCM conversion research above 90% at 400 °C, and only decrease 8.6% after 50 h reaction at 450 °C, suggesting that as-synthesized 2D alumina slice has potential application for highly efficient removal of low-concentration methane from ventilation air.
研究领域:
材料科学
·
环境科学
✓ 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）