查找使用阿拉丁产品的科研文献

A Novel Strategy for the Preparation of Supported Pd as an Efficient Catalyst for the Hydrogenation of Nitrobenzene in Mild Conditions

Zhi Hu,Yiyi Cheng,Meng Wu,Ying Duan,Yanliang Yang,Tianliang Lu

An advanced strategy was developed for the synthesis of molecular sieve-supported Pd catalysts. In this method, reductant containing C=C was in-situ prepared and pre-dispersed in the pore of the zeolites. The C=C group in the reductant can reduce the Pd2+to Pd0efficiently, leading to the formation of small and uniform Pd nanoparticles (~2 nm). The physical and chemical properties of the catalyst were characterized by XRD, TEM, XPS (ICP-OES), N2isothermal adsorption-desorption, and H2-TPR. These catalysts showed high catalytic performance for the hydrogenation of nitrobenzene to aniline. All the TOFs for 1.5 Pd/Y, 1.5 Pd/ZSM-5, and 1.5 Pd/MOR with 1.5 wt% Pd loading are higher than 1000 h−1at 30 °C and 0.1 MPa H2. Meanwhile, kinetic analysis for 2.0 Pd/Y was carried out, and an apparent activation energy of 28.88 kJ mol−1was obtained, which is lower than most of the reported values in the literature. Furthermore, these catalysts were stable and recyclable.Keywords:Pd;in-situ reduction;hydrogenation;molecular sieve

Quercetin/Anti-PD-1 Antibody Combination Therapy Regulates the Gut Microbiota, Impacts Macrophage Immunity and Reshapes the Hepatocellular Carcinoma Tumor Microenvironment

Ruoxia Wu,Jiaqing Xiong,Ting Zhou,Zhen Zhang,Zhen Huang,Sha Tian,Yongli Wang

Objective: The use of immune checkpoint inhibitors (ICIs) provides promising strategies for hepatocellular carcinoma (HCC) treatment. This study aimed to explore impact and underlying mechanism of the combination therapy of quercetin and anti-programmed cell death 1 (anti-PD-1) antibody on HCC. Methods: Orthotopically transplanted HCC tumors in mice were treated with quercetin, anti-PD-1 antibody, or a combination of both therapies. Histopathological changes and programmed cell death ligand 1 (PD-L1) expression were characterized by hematoxylin and eosin (H&E) and immunohistochemistry (IHC) staining. The diversity and differences of gut microbiota (GM) were evaluated through 16S rRNA sequencing. Levels of macrophage immunity-related cytokines were quantified by enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (RT-qPCR), and Western blot. Results: Combination therapy reduced necrosis, fibrosis, and PD-L1 expression in liver tissues. Additionally, combination therapy reduced GM imbalance and increased abundance of Firmicutes, Actinobacteria, and Verrucomicrobiota at the phylum level as well as Dubosiella and Akkermansia at the genus level. Combination therapy improved macrophage immunity, raised the expressions of CD8a, CD4, CD11b, interleukin (IL)-10, and interferon (IFN)-γ , and declined the expressions of IL-4, IL-6, toll-like receptor 4 (TLR4), an inhibitor of nuclear factor κBα (IκBα), and the NFκB subunit p65. Upon combination therapy, expressions of M2 macrophage-related genes arginase-1 (Arg-1), IL-10, transforming growth factor-β (TGF-β), and matrix metalloproteinase-9 (MMP-9) were upregulated. Instead, M1 macrophage-related genes IL-6, IL-12a, IL-1β, and tumor necrosis factor-α (TNF-α) were downregulated. Conclusions: Quercetin/anti-PD-1 antibody combination therapy reshaped HCC tumor microenvironment in mice in parallel with regulating the GM and macrophage immunity.

Pd nanoparticles supported on porous N-doped carbon derived from ZIF-8: a facile and efficient catalyst for reduction of nitrophenols

Tang Yukuai,Chen Su,Liang Yusheng,Han Fengyan

We report a facile strategy to prepare the Pd nanoparticles loaded on porous N-doped carbon by direct carbonization of zeolitic imidazolate framework (ZIF-8) at 1000 o C. ZIF-8 not only serves as a precursor for N-doped carbon but also provides a framework to confine Pd nanoparticles with small size. The resulting Pd/ZIF-8(1000) has a regular morphology and excellent catalytic activity towards the reduction of nitrophenols (2-NP, 3-NP, and 4-NP) at room temperature with NaBH 4 as a reductant in aqueous solution. The enhanced performance is mainly due to N-doping, uniform dispersion and average size (2.3 nm) of Pd nanoparticles, large surface area, and synergistic effect between the metals (Pd NPs) and the support. Moreover, Pd/ZIF-8 (1000) remains the activity even after the 10th recycle experiment, indicating the catalyst has good stability. Importantly, ZIF-8(1000) can be applied as a framework to support highly uniform and stable noble metals with small size.

Novel Dual-Mode NIR-II/MRI Nanoprobe Targeting PD-L1 Accurately Evaluates the Efficacy of Immunotherapy for Triple-Negative Breast Cancer

Wan-Ling Liu,Yong-Qu Zhang,Xiang-Jie Luo,Yuan-Yuan Zhu,Liang Song,Zi-He Ming,Li-Xin Zhang,Meng-Jun Li,Rui-Chan Lv,Guo-Jun Zhang,Min Chen

Interfacial heterojunction construction by introducing Pd into W18O49 nanowires to promote the visible light-driven photocatalytic degradation of environmental organic pollutants

Ping Li,Zhihua Zhuang,Ziwei Zhang,Jinhan Guo,Zhongying Fang,Wei Chen

Photocatalytic degradation of organic dyes by sunlight can greatly simplify the catalytic devices and save the cost. The development of photocatalysts for organic pollutants degradation driven by sunlight at room temperature still faces serious challenges. In this work, we developed a novel Pd-W 18 O 49 nanowire photocatalyst for high efficiency, high stability, and sunlight-induced degradation of methylene blue and neutral red. It was found that after Pd introducing, the band gap energy of W 18 O 49 nanowires lowers from 2.77 to 2.44 eV, which can accelerate the electron jump from the valence band to the conduction band, resulting in the efficient separation of electrons and holes. Meanwhile, with Pd introducing to the W 18 O 49 nanowires, interfacial heterojunction with the Schottky barrier is formed, which can reduce the rate of electron-hole recombination. The catalytic results show that the obtained Pd-W 18 O 49 nanowires demonstrate enhanced photodegradation capacity in comparison with W 18 O 49 nanowires. Especially, with Pd-W 18 O 49 nanowires (10 mg) as photocatalyst, 98.4% of methylene blue and 96.1% of neutral red can be decomposed within 40 min under sunlight irradiation. Besides, the photocatalytic degradation pathways of methylene blue and neutral red on the Pd-W 18 O 49 nanowires are also proposed. This study provides a good strategy for the design and preparation of highly efficient 1D heterojunction-based photocatalysts for the degradation of environmental organic pollutants.

High-performance Pd-N (N = Ga or Ag) bimetallic monolithic catalyst for the hydrogenation of 2-ethylanthraquinone: Experimental and DFT studies

Yanyan Guo,Yichun Dong,Zhigang Lei,Zhixue Liu,Jiqin Zhu

The catalytic performance of Pd-N/Silicon Dioxide/Cordierite (Pd-N/SD/C) ( N  = Ga and Ag) bimetallic monolithic catalysts for 2-ethylanthraquinone (eAQ) hydrogenation was investigated. Catalyst characterization by HRTEM, XPS, and TPR reveal that Pd-Ga/SD/C can form an alloy structure to produce significant synergetic effects. Moreover, the use of different Pd/Ga mass ratio in catalysts reveals that when the mass ratio of Pd and Ga/Ag = 2:1, Pd-Ga/SD/C obtains the highest yield of H 2 O 2 and selectivity toward active quinones, which can reach 7.4 g L −1 and 90%. Moreover, to have a deep understanding of the eAQ-PdN(1 1 1) or eAQ-Pd(1 1 1) interaction mechanism, the calculation of eAQ adsorption on Pd-N/SD/C catalysts surface was performed by density functional theory (DFT). It is shown that the higher catalytic activity over Pd-Ga/SD/C is due to the stronger carbonyl group of eAQ adsorption on Pd 3 Ga 1 (1 1 1).

The electrochemical reforming of glycerol at Pd nanocrystals modified ultrathin NiO nanoplates hybrids: An efficient system for glyceraldehyde and hydrogen coproduction

Ma Ge,Yang Na,Zhou Guofu,Wang Xin

The glycerol electro-oxidation reaction (GEOR) is a green and promising method for the glyceraldehyde production. In this work, Pd nanocrystals (Pd-NCs) modified ultrathin NiO nanoplates (NiO-uNPs) hybrids (Pd-NCs/NiO-uNPs) are successfully synthesized using successive cyanogel hydrolysis, chemical reduction, and calcination treatment methods. Various electrochemical measurements and physicochemical characterization results demonstrate that Pd-NCs/NiO-uNPs hybrids have excellent electrocatalytic performance for both GEOR and hydrogen evolution reaction (HER) in alkaline medium, which benefit from the large specific surface area, uniform distribution of Pd-NCs, and the modified electronic structure of Ni atoms. At Pd-NCs/NiO-uNPs hybrids, only 1.43 V is needed to obtain the current density of 100 mA·cm −2 for GEOR, much lower than that for oxygen evolution reaction (1.82 V). In addition, Pd-NCs/NiO-uNPs hybrids exhibit better HER performance than commercial Pd/C electrocatalyst. As a result, the constructed Pd-NCs/NiO-uNPs‖Pd-NCs/NiO-uNPs glycerol electrolyzer only requires 1.62 V electrolysis voltage to reach 10 mA·cm −2 current density, showing an energy-efficient and economy-competitive synthesis for the coproduction of glyceraldehyde and hydrogen.

Au-Pd nanoparticles immobilized on TiO2 nanosheet as an active and durable catalyst for solvent-free selective oxidation of benzyl alcohol

Zhe Wang,Jiangjiang Feng,Xiaoliang Li,Rena Oh,Dongdong Shi,Ouardia Akdim,Ming Xia,Liang Zhao,Xiaoyang Huang,Guojie Zhang

TiO 2   nanocrystals with controlled facets have been extensively investigated due to their excellent photocatalytic performance in sustainable and green energy field. However, the applications in thermal catalysis without applying UV irradiation are comparably less and the identification of their intrinsic roles, especially the different catalytic behaviors of each crystal facet, remains not fully recognized. In this study, bimetallic AuPd nanoparticles supported on anatase TiO 2 nanosheets exposing {0   0   1} facets or TiO 2 nanospindles exposing {1   0   1} as a catalyst were prepared by sol-immobilization method and used for solvent-free benzyl alcohol oxidation . The experimental results indicated that the exposed facet of the support has a significant effect on the catalytic performance. AuPd/TiO 2 -001 catalyst exhibited a higher benzyl alcohol conversion than that of the AuPd/TiO 2 -101. Meanwhile, all the prepared AuPd/TiO 2 catalysts were characterized by XRD , ICP-AES, XPS, BET, TEM, and HRTEM . The results revealed that the higher number of oxygen vacancies in TiO 2 -sheets with the exposed {0   0   1} facets of higher surface energy could be responsible for the observed enhancement in the catalytic performance of benzyl alcohol oxidation. The present study displays that it is plausible to enhance the catalytic performance for the benzyl alcohol oxidation by tailoring the exposed facet of the TiO 2 as a catalyst support.

Preparation of nickel-foam-supported Pd/NiO monolithic catalyst and construction of novel electric heating reactor for catalytic combustion of VOCs

Xiao Chen,Jianyu Li,Yue Wang,Ying Zhou,Qiulian Zhu,Hanfeng Lu

Metal-based monolithic catalysts have excellent electrical and thermal conductivity, impact resistance, ductility, and mechanical properties. Thus, they have a broader application prospect than ceramic-based monolithic catalysts. In this work, high-dispersion Pd nanoparticle dispersion liquid was synthesized by using the solvothermal method. Moreover, nickel-foam-supported Pd/NiO (Pd/NiO/Ni foam) monolithic catalyst with good catalytic combustion performance was prepared successfully by simply spraying the dispersion liquid on the surface of Ni foam, which was oxidized at high temperature to grow NiO film. A novel electric heating catalytic combustion reactor with fast response and safety was constructed by nesting Pd/NiO/Ni foam with an insulated heating rod. Notably, even at the high space velocity of 50,000 h −1 , the constructed reactor can completely degrade 2500 ppm of toluene at 230 ℃ and exhibits good catalytic activity for hydrocarbons and oxygen-containing and heteroatom-containing organic compounds.

A facile one-step method for the fabrication of Pd-AlOOH/Al monolithic catalysts via redox reactions of two galvanic cells

Liu Fangfang,Xu Zehua,Feng Ying,Li Yongfeng,Dou Yongshen,Liu Sanmao

In this work, we report a facile and economic one-step method under atmospheric pressure and 50 °C water bath for the fabrication of a three-dimensional (3D) upright-standing boehmite (AlOOH) nanosheet array film on a structured Al honeycomb substrate, in which zero-valence palladium (Pd 0 ) nanoparticles were well distributed at the same time. Redox reactions of two galvanic cells where the Al honeycomb substrate acted as the common anode, but the palladium precursor (Pd(NH 3 ) 4 2+ ) and weak base water (H 2 O + OH − ) served as the electrolyte of cathode I and II, respectively, led to simultaneous formation of Pd 0 nanoparticles at cathode I and AlOOH nanosheets at cathode II on the surface of Al substrate. The resultant AlOOH nanosheet array was uniform and about 300–400 nm thick, and the highly dispersed Pd 0 nanoparticles were also rather small with an average size of 8.4 nm. Hence, the as-obtained Pd-AlOOH/Al monolithic catalysts exhibited high specific surface area and large micro/mesopore structure as compared to pristine Al honeycomb substrate, leading to excellent catalytic activity in total oxidation reaction of toluene.

Control of the separation order of Au(III), Pd(II), and Pt(IV) achieved by site-controllable carboxyl-functionalized diethylaminoethyl celluloses

Guo Wanghuan,Zhao Zhigang,Yang Fan,Xie Meiying,Shao Zhiheng,Xue Liyan,Zhang Yang,Lin Wanqing,Du Chang,Zhang Yongjian

Abstract The separation and recovery of Au(III), Pd(II), and Pt(IV) is a challenge in hydrometallurgy, and finding good adsorbents is a way to solve this problem. In this work, two novel adsorbents, carboxymethyldiethylammoniumethyl cellulose (CM-n-DEAEC) and carboxymethyl-2-diethylaminoethyl cellulose (CM-o-DEAEC), were synthesized by changing the grafting site of carboxymethyl on diethylaminoethyl cellulose (DEAEC). The structures and morphologies of the adsorbents were examined by NMR, FT-IR, EA, TGA, and SEM analyses. The effects of adsorbents on the separation performance of Au(III), Pd(II), and Pt(IV) at different adsorption conditions were studied. The performances of stripping and recycling were investigated. At a 3 M chloride ion concentration, CM-n-DEAEC's adsorption rates for Pd(II), Au(III), and Pt(IV) were stabilized at 60%, 30%, and 7% in the pH range of 1.0–3.0 and were unaffected by coexisting metal ions. However, at a 0.1 M chloride ion concentration, CM-o-DEAEC separated Pt(IV) before Au(III) and Pd(II) in the pH range from 1.0 to 2.0 without being affected by coexisting metal ions. In addition, the absorbed metal ions can be easily stripped by a 0.1 M thiourea-0.1 M HCl solution, and the adsorption rate only decreased by 3.0% and 1.8% after seven adsorption–desorption cycles. Therefore, it was shown that CM-n-DEAEC and CM-o-DEAEC are excellent adsorbents that can control the adsorption order of precious metals and can selectively and quickly recover Pd(II) or Pt(IV) from wastes containing Au(III). Graphic abstract

Ultrasensitive determination of ractopamine based on dual catalytic signal amplification by Pd nanocubes and HRP using a flow injection chemiluminescence immunoassay

Yingqi Pei,Jing Zhang,Kang Wu,Anping Deng,Jianguo Li

A rapid and highly sensitive flow injection chemiluminescence immunoassay was developed to detect ractopamine residues in pork products. Palladium nanocubes with excellent catalytic performance for a traditional luminol–PIP–H2O2 chemiluminescence system were used as effective carriers to connect a ractopamine antibody and horseradish peroxidase (HRP). Double amplification of a chemiluminescence signal was realized because of palladium nanocubes and HRP. Carboxyl-modified resin beads were used as suitable materials to load ractopamine-coating antigens due to their good biocompatibility and large specific surface area. Based on the principle of competitive immunity, ractopamine standard solution would compete with antigen loaded on carboxyl resin beads for limited binding sites on a ractopamine antibody. Thus, the chemiluminescence intensity of an immunosensor has a linear negative correlation with the logarithm value of ractopamine concentration. Under optimal experimental conditions, the detection range of ractopamine was 0.005–1000 ng mL−1, and the limit of detection (LOD) was 1.7 pg mL−1 (S/N = 3). The proposed immunoassay possessed acceptable accuracy, high specificity and reproducibility and RAC was examined in pork and pig feed with satisfactory results, which would provide a better prospect for the detection of small molecules in food and environment analysis.