APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Li Zhang,Weiwei Lu,Peng Xu,Hao Wang,Xuefeng Wei,Kaisheng Yao,Shuge Peng
In this study, we propose a novel photo-activation method to remove persistent organic pollutants through a SO4˙ˉ-based advanced oxidation process . Core–shell Ag@Pd nanocubes were prepared by a facile seed-mediated method and, afterward, explored for photodegradation of a representative ionic liquid (IL), [C 4 mim]Br. Electron paramagnetic resonance measurements and radical scavenging experiments demonstrated that the species mainly responsible for degrading [C 4 mim]Br were the radicals of SO4˙ˉ. The plasmon-mediated nature of the Ag@Pd catalysts was verified by their wavelength-dependent performance. Subsequent optical simulation indicated that, other than the plasmonic Ag core, the non-plasmonic Pd shell was the preferential site for dissipating the absorbed photons into energetic charge carriers to produce the radical species. Finally, based on the detected intermediates, we propose the degradation pathway of ILs in the plasmon-mediated process. The results of our method suggest favorable application in the treatment of wastewater.
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Journal of Materials Chemistry A
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2020
·Vol. 8
·期 34
·17657-17669
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IF 11.301
Xiaoli Li,Ting Wang,Xueqin Tao,Ganhua Qiu,Can Li,Benxia Li
Metal-modified semiconductors are being deemed as one of the most promising photocatalysts for various applications. Although great efforts have been devoted to developing a variety of metal-modified semiconductor photocatalysts, the exact functions of their interfaces in governing photocatalytic processes still remain elusive. Herein, the interfacial synergy of metal sites and defective semiconductor with oxygen vacancies (VOs) was investigated toward the photocatalytic selective oxidation of toluene, by taking the Pd/BiOBr photocatalyst as an example. The presence of Pd induces the generation of more VOs on the BiOBr surface due to the electronic interaction at the Pd–BiOBr interface. The coexistence of the Pd and VO sites on BiOBr enables the favorable adsorption of O2 and toluene molecules. The Pd–BiOBr interface governs the charge separation and prompts the activation of O2 and toluene, leading to 1.5 times the activity of BiOBr–VO for the photocatalytic selective oxidation of toluene to benzaldehyde with a high selectivity (>99%). Moreover, the typical influencing factors, such as the illumination intensity and toluene concentration, were optimized to improve the photocatalytic efficiency. The active species and intermediates in the photocatalytic reaction were identified by a series of controlled experiments, as well as in situ ESR measurements. Therefore, both experimental and theoretical results provide the direct evidence to understand the key roles of the interfacial Pd and VO sites in enhancing photocatalysis toward the selective oxidation of toluene.
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ACS Catalysis
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2020
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IF 12.35
Feng Jiang,Shanshan Wang,Bing Liu,Jie Liu,Li Wang,Yang Xiao,Yuebing Xu,Xiaohao Liu
CeO2 is an excellent potential material for CO2 hydrogenation attributed to the highly tunable properties including metal–support interaction and abundant oxygen vacancy. In this work, four CeO2 supports with structurally well-defined different shapes and crystal facets are hydrothermally prepared, and their effects on the composition of Pd species and oxygen vacancy over Pd/CeO2 catalysts have been intensively investigated in the reduction of CO2 to methanol. The 2Pd/CeO2-R (rods) shows the highest concentration and number of oxygen vacancies, where the (110) facet with high surface oxygen mobility and low oxygen vacancy formation energy is exposed over the CeO2-R surface. The oxygen mobility at the interface of (111) and (100) facets mainly observed on 2Pd/CeO2-P (polyhedrons) is higher than the single (111) and (100) facets mainly observed on 2Pd/CeO2-O (octahedrons) and 2Pd/CeO2-C (cubs), respectively. The presence of Pd highly promotes the formation of oxygen vacancies by providing dissociated H atoms to facilitate the removal of surface O in ceria support under a H2 atmosphere. Both the PdxCe1–xOδ solid solution dominated on CeO2-R and the PdO species dominated on CeO2-O are reduced to metallic Pd after reduction with 6–10 nm average particle size. As revealed by density functional theory (DFT) calculations, in contrast to the single Pd0 atom on CeO2 and the thermodynamically most unstable PdxCe1−xOδ solid solution, the Pd0 nanoparticles are the most stable species under the realistic reaction conditions. The 2Pd/CeO2-R shows the highest catalytic activity as the abundantly available oxygen vacancies function as CO2 adsorption and activation sites. Moreover, oxygen vacancy reactivity is correlated with its formation energy. The lower formation energy facilitates the formation of oxygen vacancy; however, the reactivity of each oxygen vacancy is lower as the TOFoxygen vacancy of 2Pd/CeO2-O is 15 times as that of 2Pd/CeO2-R. Thus, a suitable oxygen vacancy formation energy is likely favorable for enhancing CO2 reactivity. DFT calculations indicate that the CH3OH formation is most probably from the formate (HCOO*) pathway via the C–O bond cleavage in H2COOH*, with the reduction of HCOO* to HCOOH* as the rate-limiting step. These results would provide experimental and theoretical insights into the rational design of an effective catalyst for CO2 hydrogenation.
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BIOCHEMICAL PHARMACOLOGY
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2020
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IF 4.96
Xuqian Deng,Jiaqi Zhao,Linlin Qu,Zhiguang Duan,Rongzhan Fu,Chenhui Zhu,Daidi Fan
Ginsenoside Rh4, as a bioactive component obtained from Panax notoginseng , has excellent pharmacological efficacy especially antitumor effects. However, its anticancer effects and target mechanisms in regulating human esophageal cancer are still poorly understood. Here, the results suggested that Rh4 exhibited potent anti-esophageal cancer effects in vivo and in vitro . Flow cytometric analysis and Western Blot showed that Rh4 significantly inhibited the growth by inducing G1 phase arrest. In parallel, Rh4 inhibited aerobic glycolysis in esophageal cancer cells by hindering lactate production, glucose uptake and ATP production; reducing the extracellular acidification rate (ECAR) and oxygen consumption rate (OCR); suppressing aerobic glycolysis-related protein expression. Mechanistic studies demonstrated that AKT is a possible target of Rh4, which suppresses aerobic glycolysis. Rh4 administration resulted in AKT deregulation, whereas treatment with insulin abolished the inhibitory effect of Rh4 on aerobic glycolysis. In contrast, treatment with AKT inhibitors or siRNA that silenced AKT enhanced the inhibitory effect of Rh4 on aerobic glycolysis. Moreover, molecular docking results indicated that Rh4 was able to bind to the interdomain region of AKT. Interestingly, the results revealed that Rh4 also inhibited the expression of PD-L1 via the AKT/mTOR pathway. Taken together, our findings provide important insights into the anti-esophageal cancer effects of Rh4 via suppressing aerobic glycolysis and PD-L1 expression, which indicated Rh4 could be as promising drug for clinical treatment.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
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IF 7.489
Fukun Bi,Xiaodong Zhang,Shang Xiang,Yunyun Wang
The effect of Pd loading (0.25, 0.5 and 1.0 wt%) and ZrO 2 support calcined at diverse temperatures (600, 700 and 800 °C) by pyrolysis of UiO-66 was investigated for CO oxidation in this work, respectively. The physicochemical properties of the samples were characterized by various characterization methods. The XRD results exhibited that all ZrO 2 support possessed mixed crystalline phase, the monoclinic ZrO 2 and tetragonal ZrO 2 . And the calcination temperature had a big impact on the composition of ZrO 2 supports. Pyrolysis of UiO-66 at high temperature was favorable for the formation of monoclinic ZrO 2 . Additionally, the introduction of Pd was induced the phase conversion from tetragonal to monoclinic of ZrO 2 . The order of catalytic efficiency was as follows: 0.5Pd/Zr-700 > 0.5Pd/Zr-600 > 0.5Pd/Zr-800. Moreover, 0.5Pd/Zr-700 presented high stability and great reusability. The good catalytic performance of 0.5Pd/Zr-700 was ascribed to the better reduction ability at low temperature and high O ads /O lat and Pd 0 /Pd 2+ on the surface. Importantly, the reaction pathway of CO oxidation over the 0.5Pd/Zr-700 was exposed.
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CHEMOSPHERE
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2020
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IF 5.778
Lun Wang,Keming Wang,Ruihua Huang,Zhen Qin,Yingchun Su,Shanshan Tong
In the past few years, two-dimensional (2D) nanomaterials have emerged great potential for the removal of valuable metals and the capture of polluted-heavy metals. Herein, hierarchically flower-like microcrystals with 2D WS 2 nanosheets (F-WS 2 MCs) were prepared by one-pot hydrothermal synthesis strategy and its adsorption performances for precious metals were systematically assessed. The excellent adsorption efficiencies of ∼86.8%, ∼27.6%, and ∼94.1% towards Ag (I), Pd (II), and Au (III) respectively were achieved within 120 min, and the adsorption curves were in good agreement with a pseudo-second-order kinetic model showing a fast uptake rate at the optimum pH values (1.30 for Au (III), 1.43 for Ag (I), and 3.20 for Pd (II)). The adsorption isotherm followed well in the Langmuir model with the maximum removal capacities ( q max ) of 186.2 mg g −1 for Ag (I), 67.29 mg g −1 for Pd (II), and 1340.6 mg g −1 for Au (III), respectively. Furthermore, for recycling purposes, the relevant desorption solution was investigated with different ratios of monobasic acid and thiourea , suggesting the best desorption efficiency of 93.03%, 88.08%, and 85.34% for Ag (I), Pd (II), and Au (III), respectively. By characterizing the crystalline phase, and micromorphology element mapping of F-WS 2 MCs before and after adsorption, the strong affinity and significant adsorption–reduction were indicated to dominate the adsorption process. Therefore, this work broadens the application range of WS 2 microcrystals, providing an alternative material for capturing precious metals and wastewater treatment applications.
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APPLIED SURFACE SCIENCE
·
2020
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IF 6.182
Mengran Lou,Ruiying Wang,Lili Yang,Dianzeng Jia,Zhipeng Sun,Luxiang Wang,Yong Guo,Xingchao Wang,Jie Zhang,Hongli Shi
Direct formic acid fuel cells have great application potential in the energy field, but their commercialization is hindered by the CO poisoning and low performance of Pd-based anode catalysts. In this study, novel composite catalysts composed of Pd, organic-inorganic hybrid imidazole ionic liquid polyoxometalates, and N,P-codoped coal-based carbon fibers with good dispersion and smaller Pd nanoparticles were synthesized successfully. Physical and electrochemical characterizations revealed that the as-prepared Pd-based composite catalysts have excellent CO poisoning resistance and enhanced electrocatalytic activity in formic acid electrooxidation. Notably, the CO oxidation onset potential of a catalyst modified by imidazole ionic liquid polyoxometalate with long alkyl chain was 0.1 V lower than that of the unmodified catalyst. The mass activity of the as-prepared Pd catalyst in formic acid oxidation was 754.1 mA mg −1 Pd . It is expected that organic-inorganic hybrid polyoxometalates can be further applied to fuel cell catalysts.
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Electrocatalysis
·
2020
·Vol. 11
·期 5
·522-535
·
IF 2.587
Shen Yanmei,Lu Shixiang,Xu Wenguo,Lv Anqi,Wang Ziwen,Wang Hongtao,Liu Guoxiao,Zhang Yan
Incorporation of precious metallic nanoparticles onto a carbon support material is used to obtain an electrocatalyst for ethanol oxidation. A composite material of spherical palladium nanoparticles (Pd NPs), reduced graphene oxide (rGO), and polydopamine (PDA) on three-dimensional nickel foam (NF) substrate (Pd/rGO/PDA@NF) has been synthesized for ethanol electrocatalysis. The Pd nanoparticles were obtained via reduction of precursor K 2 PdCl 4 using ascorbic acid at 60 °C for 80 min. The rGO with large specific surface area was used in catalysts to provide large amounts of active sites for Pd NPs. Meanwhile, Pd NPs as an effective ingredient in catalyst exhibited excellent electrochemical activity of ethanol oxidation. Local surface plasmon resonance was carried out to determine the optimal concentration of precursor K 2 PdCl 4 aqueous solution, and the absorbance peak of Pd NPs was found at about 340–370 nm by UV-visible spectroscopy. An enhanced property of the composite material Pd/rGO/PDA@NF was demonstrated to catalyze the ethanol oxidation reaction in alkaline electrolyte solution. A higher ratio of forward scan peak current intensity ( I f ) to reverse scan peak current intensity ( I b ) was 1.59, which demonstrated the significant anti-poison effect to carbonaceous intermediates of the Pd/rGO/PDA@NF. The value of I f can maintain 90.6% after 400 cycles, indicating the higher cycling stability and better electrocatalytic performance toward ethanol oxidation.
Pd/rGO/PDA@NF was synthesized by a simple method with great elecrocatalytic performance and tolerance against carbonaceous intermediate species toward ethanol oxidation.
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NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 44
·期 9
·3681-3689
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IF 3.288
Yizhu Lei,Zaifei Chen,Guosong Lan,Renshu Wang,Xiao-Yu Zhou
Small palladium nanoparticles stabilized with phosphine-functionalized porous ionic polymer (Pd@P(QP-TVP)) were successfully prepared through a free-radical copolymerization, successive anion-exchange and chemical reduction method. Physicochemical characterization studies suggested that the prepared catalyst featured large surface area, a hierarchically porous structure, amphiphilic surface wettability, and strong electron interaction between Pd nanoparticles and the polymer scaffold. We demonstrated the use of the solid catalyst for water-mediated reduction of nitrobenzene with H2 as a hydrogen source. Notably, a low Pd dosage was sufficient for a high yield (99.7%) of aniline with a remarkable turnover frequency (TOF) of 5982 h−1. Furthermore, the Pd@P(QP-TVP) catalyst can be easily recovered and reused at least 5 times without significant loss of activity. Additionally, a number of functional nitroarenes can be efficiently transformed to arylamines in high yields under optimal conditions. Thus, this work provided a highly active, stable and heterogeneous Pd catalyst for the environmentally benign and cost-effective hydrogenation of nitroarenes.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Naseeb Ullah,Zhaoqi Song,Wei Liu,Chi-Ching Kuo,Aymeric Ramiere,Xingke Cai
Controlled synthesis of noble metal nanoparticles with well-defined size and good dispersion on supports has been a long-standing challenge in heterogeneous catalysis. Here we report a facile photo-assisted H 2 in situ reduction process to synthesize monodispersed Pd nanoparticles with 2–4 nm size on photo-insensitive Sm 2 O 3 rare-earth metal oxide with nanorod morphology. Thanks to the contribution of UV irradiation, the photoelectrons generation in the Sm 2 O 3 support accelerates the H 2 reduction of Pd 2+ ions into Pd 0 and stabilize the growth of very small Pd nanoparticles homogeneously dispersed on the support. The homogeneous distribution of the Pd NPs on the surface of Sm 2 O 3 is most likely attributed to the profuse nucleation sites created by the UV irradiation and the abundance of hydroxyl groups on the support. The hydrogenation of styrene to ethylbenzene was studied as a model reaction. As a result, the UV radiated sample shows an excellent TOF value of 7419 h −1 , which is quadruple of the sample without UV irradiation, under the condition of 0.1 MPa H 2 at a content of 1.0 wt% Pd. Besides, UV radiated sample shows a negligible performance degradation during the repeated cycling process. This photo-promoted H 2 reduction process provides a convenient and straightforward route for assembling materials with novel structures and functions for nanotechnology applications.
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BIOELECTROCHEMISTRY
·
2021
·
IF 5.373
Fenglin Zhang,Zhiguang Liu,Yujie Han,Lifang Fan,Yujing Guo
Carcinoembryonic antigen (CEA) is considered as a disease biomarker, which is related to various cancers and tumors in the human bodies. Sensitive detection of CEA is significant for clinical diagnosis and treatment. Herein, we proposed an electrochemical aptasensor for CEA detection based on the amplification driven by polydopamine functional graphene and Pd-Pt nanodendrites ( [email protected] /Pd-PtNDs), conjugated hemin/G-quadruplex (hemin/G4), which possess mimicking peroxidases activity. Firstly, [email protected] was modified on the electrode surface for fixing CEA aptamer 1 (Apt1). Then, [email protected] /Pd-PtNDs with large surface area served as matrix for immobilization of hemin/G4 to obtain the secondary aptamer. In virtue of the sandwich-type specific reaction between CEA and the corresponding aptamers, the second aptamer was captured on the sensing interface, which can catalyze the oxidation of signal probe hydroquinone (HQ) with H 2 O 2 and amplify current signal. Furthermore, the electrochemical signals of HQ were proportional with CEA concentrations. Under the optimal conditions, a dynamic response range from 50 pg/mL to 1.0 μg/mL and a detection limit of 6.3 pg/mL for CEA were obtained. Moreover, the proposed strategy represented satisfactory sensitivity and stability, and showed a good precision in real samples application.
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CHEMICAL ENGINEERING JOURNAL
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2021
·
IF 13.273
Lehui Ren,Mei Chen,Jinxing Ma,Yang Li,Zhiwei Wang
In this study, a novel reactive electrochemical membrane (REM) made of Pd-loaded porous Ti was prepared to achieve ultrafast and efficient oxidation of trace antibiotics sulfamethoxazole (SMX) under anodic polarization. At a current density of 0.5 mA/cm 2 , the percentage removal of SMX by the REM was 96.3% in flow-through mode, with the energy cost ( i.e. , the electrical energy per order of removal, 1.34 Wh/m 3 ) being much lower than the flow-by mode (125.76 Wh/m 3 ) under the same operating condition. Quenching experiments and electron spin resonance spectra demonstrated that singlet oxygen ( 1 O 2 ) was the main reactive oxygen species in the REM system, playing a vital role in SMX degradation. Results of this study indicated that 1 O 2 was mainly generated on the anode via Pd–O 2 interaction that directly activated oxygen, rather than the evolution of 1 O 2 precursors ( e.g ., O 2 − and H 2 O 2 ). The constantly high electrochemical removal of SMX (88.5–91.9%) from actual surface water demonstrated that the matrix effect on the process performance was minimal in realistic applications, highlighting this novel REM to be a viable way to remove trace organic contaminants from surface water.
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