JOURNAL OF APPLIED PHYSICS
·
2023
·Vol. 134
·期 8
·
IF 3.2
Li Gaojie,Zhang Linqi,Du Kai,Wang Xinxin,Yin Menghao
Reducing the working temperature and increasing sensitivity and selectivity has always been a research hotspot in the field of MOS based gas sensors. In this work, improved triethylamine (TEA) sensing performance and mechanism of SnO 2 by doping Pd have been investigated. SnO 2 nanoparticles and Pd-SnO 2 with different doping amounts of Pd (0%, 0.1%, 0.3%, 0.5%, and 0.7%) were successfully prepared by the hydrothermal method. The size of SnO 2 nanoparticles is very uniform (∼15 nm). The SnO 2 sensor exhibited the highest sensitivity to ethanol at 290 °C. After Pd doping, Pd/SnO 2 sensors not only reduced the optimum working temperature but transformed selectivity from ethanol to TEA. In the Pd-SnO 2 system, the 0.5Pd-SnO 2 sensor exhibited high sensitivity (61), fast response-recovery properties (16 s/6 s) to 50 ppm TEA, lower detection limits (0.1 ppm), good repeatability, and higher selectivity. Furthermore, based on density functional theory calculations, the improved TEA sensing performance of 0.5Pd-SnO 2 sensors can be attributed to the improved surface activity of SnO 2 by Pd doping and the catalytic activation of O 2 and TEA by Pd.
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ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Di Chuan,Rangrang Fan,Bo Chen,Yangmei Ren,Min Mu,Haifeng Chen,Bingwen Zou,Haohao Dong,Aiping Tong,Gang Guo
In developing countries, the incidence of colorectal cancer (CRC) is on the rise. The combination of programmed cell death ligand-1 (PD-L1) siRNA (siPD-L1) and mild photothermal therapy (PTT) is a promising strategy for CRC treatment. In this study, dopamine-modified polyethylenimine (PEI) was prepared to fabricate an IR780 and siPD-L1 codelivery lipid–polymer hybrid nanoparticle (lip@PSD-siP) for the photothermal immunotherapy of CRC. The modification of dopamine can significantly reduce the cytotoxicity of PEI. lip@PSD-siP can be effectively taken up by CT26 cells and successfully escaped from lysosomes after entering the cells for 4 h. After CT26 cells were transfected with lip@PSD-siP, the PD-L1 positive cell rate decreased by 82.4%, and its PD-L1 knockdown effect was significantly stronger than the positive control Lipo3000-siP. In vivo studies showed that lip@PSD-siP-mediated mild PTT and efficient PD-L1 knockdown exhibited primary and distal tumor inhibition, metastasis delay, and rechallenged tumor inhibition. The treatment with lip@PSD-siP significantly promoted the maturation of dendritic cells in lymph nodes. The amount of T cell infiltration in the tumor tissues increased significantly, and the frequency of CD8+ T cells and CD4+ T cells was significantly higher than that of other groups. The percentage of immunosuppressive regulatory cells (Tregs) in the tumor tissue on the treatment side decreased by 88% compared to the PBS group, and the proportion of CD8+CD69+ T cells in the distal tumor tissue was 2.8 times that of the PBS group. The memory T cells of mice in the long-term antitumor model were analyzed. The results showed that after treatment with lip@PSD-siP, the frequency of effector memory T cells (Tem cells) significantly increased, suggesting the formation of immune memory.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Jinwu Hu,Ran Li,Xin Wang,Shaozhen Wang,Caihong Fang
Constructing an appealing architecture is of great significance to improving the electrocatalytic activity and stability of Pt-based nanocatalysts. In this work, we successfully synthesized porous Pd@PdPt core/shell nanocrystals via a facile one-pot method, which possess several architectural and compositional advantages, involving porous outer, ultrathin branches, an open mesoporous skeleton, a core/shell structure, and an alloyed composition. These morphological features and the synergistic effect between different components in the alloy endow the Pd@PdPt nanostructures with abundant active sites, effective mass transfer, strain in the particle, and the electronic coupling effect. The Pd@PdPt nanoalloy therefore exhibits excellent electrocatalytic performances in alcohol oxidation reactions. Impressively, the Pd5Pt4 nanocubes exhibit a higher mass/specific activity of 3.225 A mgPt+Pd–1/34.49 A m–2 for the ethanol oxidation reaction, which is even 4.00-/2.39-fold as high as that of commercial Pt/C. Moreover, the Pd5Pt4 nanocubes also show a superior mass activity of 2.824 A mgPt+Pd–1/37.66 A m–2 toward the methanol oxidation reaction, which is up to 4.20/2.40 times that of the commercial Pt/C. The Pd@PdPt also has enhanced electrocatalytic stability. More importantly, the porous Pt5Pd4 nanocubes still demonstrate superior electrocatalytic activities of 0.259, 1.19, 2.65, and 2.76 A mgPt+Pd–1 for the oxidation of glucose, isopropyl alcohol, glycerol, and ethylene glycol, respectively. We therefore believe that these universal electrocatalysts have the potential to promote practical applications in fuel cells.
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Small
·
2021
·Vol. 18
·期 9
·2105118
·
IF 13.281
Yu Hei,Yang Chen,Qian Li,Zi Mei,Jijia Pan,Siqi Zhang,Chunyang Xiong,Xiaodong Su,Shicheng Wei
The immunosuppressive tumor microenvironment (TME) can significantly limit the immunotherapeutic effects of the PD-L1 antibody (aPDL1) by inhibiting the infiltration of CD8 + cytotoxic T cells (CTLs) into the tumor tissues. However, how to reprogram the immunosuppressive TME and promote the infiltration of CTLs remains a huge challenge for aPDL1 to achieve the maximum benefits. Herein, the authors design a multifunctional immunoliposome that encapsulates the adrenergic receptor blocker carvedilol (CAR) and connects the “don't eat me” signal antibody (aCD47) and aPDL1 in series via a reactive oxygen species (ROS)-sensitive linker on the surface. In ROS-enriched immunosuppressive TME, the multifunctional immunoliposome (CAR@aCD47/aPDL1-SSL) can first release the outer aCD47 to block the “do not eat me” pathway, promote the phagocytosis of tumor cells by phagocytic cells, and activate CTLs. Then, the aPDL1 on the liposome surface is exposed to block the PD-1/PD-L1 signaling pathway, thereby inducing CTLs to kill tumor cells. CAR encapsulated in CAR@aCD47/aPDL1-SSL can block the adrenergic nerves in the tumor tissues and reduce their densities, thereby inhibiting angiogenesis in the tumor tissues and reprogramming the immunosuppressive TME. According to the results, CAR@aCD47/aPDL1-SSL holds an effective way to reprogram the immunosuppressive TME and significantly enhance immunotherapeutic efficiency of aPDL1 against the primary cancer and metastasis.
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Foods
·
2023
·Vol. 12
·期 23
·4260
·
IF 5.2
Yuan Fang,Shusen Ding,Weiran Li,Jingjing Zhang,Hui Sun,Xiaodong Lin
Silver ions (Ag+) exist widely in various areas of human life, and the food contamination caused by them poses a serious threat to human health. Among the numerous methods used for the detection of Ag+, fluorescence and colorimetric analysis have attracted much attention due to their inherent advantages, such as high sensitivity, simple operation, short time, low cost and visualized detection. In this work, Pd/Pt nanoflowers (NFs) specifically responsive to Ag+were synthesized in a simple way to oxidize o-phenylenediamine (OPD) into 2,3-diaminophenazine (DAP). The interaction of Ag+with the surface of Pd/Pt NFs inhibits the catalytic activity of Pd/Pt NFs towards the substrate OPD. A novel dual-channel nanosensor was constructed for the detection of Ag+, using the fluorescence intensity and UV-vis absorption intensity of DAP as output signals. This dual-mode analysis combines their respective advantages to significantly improve the sensitivity and accuracy of Ag+detection. The results showed that the limit of detection was 5.8 nM for the fluorescence channel and 46.9 nM for the colorimetric channel, respectively. Moreover, the developed platform has been successfully used for the detection of Ag+in real samples with satisfactory recoveries, which is promising for the application in the point-of-care testing of Ag+in the field of food safety.Keywords:silver ions;Pd/Pt nanoflowers;fluorescent sensor;colorimetric sensor
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2023
·Vol. 415
·期 29
·7103-7115
·
IF 4.3
Li Guiyin,Li Xinhao,Xu Wenfeng,Li Shennan,Tan Xiaohong,Liang Jintao,Zhou Zhide
1,5-anhydroglucitol (1,5-AG) is of considerable clinical relevance as a biochemical marker of glucose metabolism in the assessment and monitoring of diabetes. Herein, a simple colorimetric biosensor was constructed for the identification and detection of 1,5-AG by using pyranose oxidase (PROD) enzyme cascaded with reduced graphene oxide/persimmon tannin/Pt@Pd (RGO-PT/Pt@Pd NPs) nanozyme. The as-prepared RGO-PT/Pt@Pd NPs had excellent peroxidase-like activity and can be applied as a nanozyme. First, PROD enzyme reacts with the target 1,5-AG, decomposing 1,5-AG into 1,5-anhydrofuctose (1,5-AF) and H 2 O 2 . At this point, the highly catalytic RGO-PT/Pt@Pd NPs nanozyme produces a cascade with PROD enzyme which catalyzes the decomposition of H 2 O 2 to produce O 2 . This in turn oxidizes the substrate 3,3′,5,5′-tetramethylbenzidine (TMB) and produces a color change in the solution. Finally, the detection of 1,5-AG was achieved by measuring the absorption peak at 652 nm with an ultraviolet visible (UV-vis) spectrophotometer. Under optimal conditions, the linear operating range of the 1,5-AG enzyme cascade colorimetric sensor was 1.0–100.0 μg/mL, and the limit of detection (LOD) was 0.81 μg/mL. The proposed colorimetric biosensor was successfully applied to detect 1,5-AG in spiked human serum samples with the recoveries of 97.2–103.9% and RSDs of 1.94–4.48%. It provides a promising developmental assay for clinical detection of 1,5-AG.
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GREEN CHEMISTRY
·
2023
·
IF 9.8
Jianhua Song,Xiaoping Wang,Lin Xu,Chonghao Chen,Dianhua Liu
Pd-catalyzed alkoxycarbonylation is an atom-efficient and green chemistry compliant protocol for ester synthesis. However, for such noble metal containing homogeneous catalytic systems, the circumvention of thermal stress deactivation of subtly designed ligands during the separation process still lacks rational countermeasures, restricting their widespread application. In this work, the coupling of efficient homogeneous catalysis and spontaneous heterogeneous separation of alkoxycarbonylation was accomplished with a rationally designed natural metabolite L-carnitine based acidic deep eutectic solvent (DES) as an acid co-catalyst. Mild and versatile alkoxycarbonylation between ethylene and long-chain aliphatic alcohols employing DES sustained exceptionally high yield (>99%) without any apparent depression in activity after long-term operation, enabling over four times the catalyst lifespan of conventional homogeneous catalysts. Catalyst recycling at the reaction temperature was implemented by the formed DES, marking it an essential milestone in improving the operational efficiency of alkoxycarbonylation. The mechanism of DES formation through synergistic interactions of proton transfer along with hydrogen bonding formation and catalyst recycling induced by ligand protonation was proposed after the molecular insight was elucidated using DFT calculation.
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APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Jinghua Li,Jia Lin,Xiaohua Chen,Meiqiu Feng,Ying Zheng
Palladium-based catalysts are relatively active for eliminating anthropogenic methane emissions through catalytic combustion, while they tend to degrade under drastic conditions. Herein, the silicon promoter was rationally introduced into Pd/ZrO 2 catalysts to tune the monoclinic ( m -) and tetragonal ( t -) phase ratio and boost the catalytic performance. The introduced Si–O–Zr structure in ZrO 2 not only reduced the grain size, but also produced oxygen vacancies due to lattice distortion, which greatly improved the stability of t -ZrO 2 in high-temperature (800 °C) calcined catalysts. However, the excessive Si-addition caused the blockage of oxygen vacancies by amorphous SiO 2 , facilitating the transformation from t -ZrO 2 to m -ZrO 2 . In the Pd/0.05Si–ZrO 2 catalyst with a relatively high t -ZrO 2 ratio, the presence of abundant oxygen vacancies stimulated the formation of surface-active oxygen and Pd 2+ species, improved the reducibility of PdO and the redox of Pd ↔ PdO, meanwhile depressed the accumulation of hydroxyls. These, coupled with the enhanced hydrophobicity by Si-modification, made Pd/0.05Si–ZrO 2 exhibit superior catalytic activity, stability and water-resistance to catalysts with low t -ZrO 2 ratio. The revealed Si-promotion effect could be generalized to design phase-regulated Pd-based catalysts with optimized surface property for catalytic oxidation reactions.
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Thermal Science and Engineering Progress
·
2023
·
IF 4.8
Jing Yi,Pan Wang,Feixiang Li,Qi Chen,Lili Lei
Catalytic combustion of C 2 H 6 at equivalence ratios of 1.0 and 1.4 over non-thermal plasma (NTP) modified Pd/Al 2 O 3 was studied experimentally to examine the effect of O 2 and N 2 plasma on the catalyst activity and physico-chemical property. C 2 H 6 conversion, chemical product distribution and selectivity were taken into account to evaluate the performance of modified catalysts in C 2 H 6 oxidation at 200–500 ℃. The results showed that the plasma modification had suppressive effects on the activity of Pd/Al 2 O 3 . When compared to Pd/Al 2 O 3 , T 30 for the modified Pd/Al 2 O 3 were shifted to higher temperatures by approximately 30–50 ℃. For catalysts modified by plasma, significantly more CO was formed in the C 2 H 6 combustion at high temperature region. Moreover, the structure, morphology and chemical states of Pd/Al 2 O 3 after modification were thoroughly analyzed with the means of N 2 adsorption–desorption, XRD, XPS and SEM. The surface area of modified catalysts decreased, resulting in the activity degradation. The leaching of Pd species and transform of γ-Al 2 O 3 to θ-Al 2 O 3 were observed after the NTP treatment with highly energetic electrons. It should to be highlighted that the reduction of Pd 2+ to Pd 0 by NTP modification on the catalyst surface from XPS analysis. The NTP had the potential to reduce catalysts while employing oxidizing or inert gases.
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APPLIED CATALYSIS A-GENERAL
·
2023
·
IF 5.5
Shuang Wang,Cheng Li,Rujie Shang,Huihui Zhang,Kehui Qi,Yao Yao,Chunyan Yu,Qing Liu,Guorui Li,Shitao Yu,Lu Li
Producing vanillin from lignin model compounds in an elegant and efficient manner is a focus of chemical utilization in lignocellulosic biomass. The facile synthesis of a cobalt-palladium bimetallic alloy anchored on activated carbon (Co-Pd/C), which excels in the selective oxidation of the lignin model compound 4-methylguaiacol to vanillin, is reported here. The characterization results of Co-Pd/C indicate that the catalysts enhance the catalytic efficiency by forming a cobalt-palladium alloy to modulate the number of d-band cavities and influence the O 2 adsorption. Meanwhile, the synergistic effect between the alloys causes the Co-Pd/C catalyst exhibits good activity and stability in cycling experiments. A series of controlled experiments offer insight into the mechanism of catalytic generation of vanillin from 4-methylguaiacol. This work opens a new opportunity for achieving the valuable aromatic products from lignin.
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Molecular Catalysis
·
2021
·
IF 5.062
Lingqi Huang,Kecheng Hu,Ganggang Ye,Zhibin Ye
Soluble small molecular/polymeric ligands are often used in Pd-catalyzed semi-hydrogenation of alkynes as an efficient strategy to improve the selectivity of targeted alkene products. The use of soluble ligands requires their thorough removal from the reaction products, which adds significant extra costs. In the paper, commercially available, inexpensive, metallic sulfide-based solid-phase ligands (SPL8-4 and SPL8-6) are demonstrated as simple yet high-performance insoluble ligands for a heterogeneous Pd nanocatalyst (Pd@CaCO 3 ) toward the semi-hydrogenation of alkynes. Based on the reactions with a range of terminal and internal alkyne substrates, the use of the solid-phase ligands has been shown to markedly enhance the selectivity of the desired alkene products by efficiently suppressing over-hydrogenation and isomerization side reactions, even during the long extension of the reactions following full substrate conversion. A proper increase in the dosage or a reduction in the average size of the solid-phase ligands enhances such effects. With their insoluble nature, the solid-phase ligands have the distinct advantage in their simple, convenient recycling and reuse while without contaminating the products. A ten-cycle reusability test with the SPL8-4/Pd@CaCO 3 catalyst system confirms its well-maintained activity and selectivity over repeated uses. A mechanistic study with x-ray photoelectron spectroscopy indicates that the solid-phase ligands have electronic interactions with Pd in the supported catalyst, contributing to inhibit the binding and further reaction of the alkene products. This is the first demonstration of solid-phase ligands for highly selective semi-hydrogenation of alkynes, which show strong promise for commercial applications.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yuan Li,Biao Pei,Junjie Chen,Shaosuo Bing,Linxiao Hou,Qi Sun,Gang Xu,Zhikan Yao,Lin Zhang
A novel catalyst with a yolk-shell structure was designed to overcome the leaching of noble metals in heterogeneous catalysis. Through a template method, palladium (Pd) nanoparticles were encapsulated by hollow spherical covalent organic frameworks (COFs) consisting of 2,4,6-trihydroxybenzene-1,3,5-tricarbaldehyde (Tp) and p-phenylenediamine (Pa). The final catalyst with a yolk-shell structure was denoted as (Pd/C)@TpPa COFs. The unique morphology and chemical structure of this novel composite (Pd/C)@TpPa COFs were confirmed by a transmission electron microscope (TEM), a laser particle analyzer, X-ray diffraction (XRD), and N 2 adsorption and desorption. Subsequently, to demonstrate its catalytic performance brought by structural design, this novel catalyst was applied to catalyze the Suzuki reaction . Interestingly, this catalyst exhibited a brilliant size cutoff efficiency for aryl benzene amounting to 100% and achieved a high conversion with only 0.05 mol% Pd loading. Besides, this catalyst could be readily recovered via filtration and reused for at least five consecutive cycles without any significant loss in its activity.
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