APL Materials
·
2023
·Vol. 11
·期 10
·
IF 6.1
Li Xia,Deng Min,Cao Tingting,Ma Jun,Geng Shuo,Ren Yuan,Yao Mengqin,Liu Fei,Dong Yonggang
Formic acid (FA, HCOOH), as a liquid chemical hydrogen storage carrier with low cost, high hydrogen content, and convenient storage and transportation, has attracted extensive attention. Pd-based catalysts for hydrogen production from FA are easy to aggregate and deactivate in the reaction process, which hinders the further development of FA as a hydrogen storage carrier. Therefore, the exploitation of carriers with simple preparation methods and excellent performance can effectively improve the catalytic activity of Pd-based catalysts. Porous carbon and SiO 2 have been widely used for their unique structural properties, and the preparation of composite carriers by combining the advantages of both is a current research hotspot. Herein, this work synthesized C–SiO 2 for the deposition of Pd nanoparticles by a one-step method, and the obtained Pd/C–SiO 2 exhibits a superior FA dehydrogenation activity with a turnover frequency value of 1278 h −1 and a favorable stability with only a slight decrease in activity after five cycles.
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JOURNAL OF NUTRITIONAL BIOCHEMISTRY
·
2022
·
IF 6.117
Qi Zhang,Wanshuang Cao,Chenying Yang,Lixia Hong,Shanshan Geng,Hongyu Han,Caiyun Zhong
The PD-1/PD-L1 immune checkpoint blockade therapy has shown revolutionary efficacy in the treatment of multiple cancers including gastric cancer. Isothiocyanates play important roles in cancer cell suppression and immunomodulation . However, the effects of isothiocyanates on immune checkpoint inhibitors are poorly understood in gastric cancer. The influence of three major isothiocyanates (sulforaphane, phenylethyl isothiocyanate, and benzhydryl isothiocyanate) on gastric cancer cell growth and PD-L1 expression was investigated. Syngeneic mouse models were administered by isothiocyanates and anti-PD-L1 monoclonal antibody , and the anti-tumor effects were assessed. The expression of PD-L1, proportion of lymphocytes and serum cytokine levels were detected to explore the underlying mechanisms. We found that PD-L1 expression was significantly induced by isothiocyanates which was associated with TAp63α up-regulation. We further revealed that TAp63α promoted PD-L1 through transcriptional activation . Combination treatment of isothiocyanates and anti-PD-L1 therapy weakened the sensitivity of gastric cancer cells to anti-PD-L1 drug. Moreover, in vivo studies illustrated that the interference effects of isothiocyanates on anti-PD-L1 antibody were related to PD-L1 expression and decreased infiltrating T lymphocytes in tumor bearing mouse hosts. Our findings provide novel insights as isothiocyanates could interfere with the successful application of immunotherapy in gastric cancer.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Nan Lu,Bin Liu,Zhengxin Peng,Jing Sui,Xiaofan Zhang,Yuting Ma,Renhong Li,Xiaoqing Yan
Rational design and fabrication of catalysts with excellent efficiency, high selectivity and outstanding stability is of great significance for the practical application of formic acid dehydrogenation into hydrogen gas. Herein, Pd catalysts with a narrow size distribution around 2.2 nm are deposited on the porous chitosan microspheres, which are produced by the polycondensation with Schiff base linkage. The Pd–N bond configuration is formed upon the abundant amino-group on the chitosan backbone with the surface anchoring Pd nanocluster. The surface charge is redistributed to generate high-valence Pd δ+ species due to the ligand-to-metal charge transfer between Pd and N, thus greatly improving the catalytic performance of formic acid dehydrogenation at room temperature and maintaining outstanding stability during 15 consecutive reaction cycles. The present work paves the way to the rational synthesis of Pd-based catalysts with tunable electronic states for practical purposes.
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Molecular Catalysis
·
2023
·
IF 4.6
Wei Tian,Yonggang Dong,Hong Qin,Ziming Luo,Qian Lin,Zheng Chen,Hongyan Pan,Yongyong Shi,Keliang Wang
The direct synthesis of hydrogen peroxide (DSHP) from hydrogen and oxygen is a green synthesis method with a high atomic economy. However, H 2 O 2 selectivity and productivity remain a key challenge, the O O bonds are easily broken with supported Pd catalysts to produce water. Herein, we report the synthesis of bimetallic catalyst PdSn@Pd@HCS by adapting reversed-phase micellar and galvanic replacement reaction. The novel bimetallic yolk-shell structure catalysts exhibit excellent catalytic performance, the selectivity and productivity of H 2 O 2 reaching 98% and 4899 mmol/g Pd· h − 1 , respectively. Theoretical calculations reveal that the presence of Sn inside the bimetallic alloy can enhance the ligand effect and optimize the electronic structure of the surface Pd atoms, weakening the adsorption ability of O 2 molecules and inhibiting the dissociation of O O bonded species, resulting in the enhancement of H 2 O 2 selectivity and productivity. This work provides the groundwork for bimetallic yolk-shell structure catalysts to achieve the efficient synthesis of H 2 O 2 .
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GREEN CHEMISTRY
·
2023
·Vol. 25
·期 15
·5999-6008
·
IF 9.8
Yuanyuan Zhang,Wanxiang Zhang,Yan Wang,Shuhang Ren,Yucui Hou,Weize Wu
To reduce the emission of NO from fossil fuel combustion and the energy consumption associated with NH3 production, the development of simple and efficient methods to transform NO into high-value-added NH3 is essential. Here, we report the efficient catalytic hydrogenation of NO to NH3 under mild reaction conditions by the synergistic catalysis of functionalized ionic liquids (FILs) and Pd catalysts. In this system, an FIL [TEPA][Im] acted as both an absorbent and a catalyst. The presence of [TEPA][Im] enhanced the catalytic performance by changing the coordination and electronic environment of Pd on the Pd/C catalyst. First, NO was absorbed by [TEPA][Im]; then, the hydrogenation of absorbed NO to NH3 was performed at a low temperature via the synergistic catalyzation of [TEPA][Im] and Pd/C. The effects of various factors on NO hydrogenation to NH3 were also investigated. Remarkably, Pd/C exhibited outstanding properties in the formation of NH3 with a high yield of 67% in the FIL [TEPA][Im] under the conditions of 100 °C and an H2 pressure of 0.5 MPa. [TEPA][Im] could be reused multiple times and the product NH3 could be recovered by flashing.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Shijie Wang,Shenghan Zhang,Zhenye Zhang,Yu Tan,Kexin Liang,Xinliang Guo,Xuhui Kong
Nitrogen heterocyclic organics are promising hydrogen storage carriers with the advantage of being capable of large-scale transportation over long distances using existing oil and gas facilities. However, traditional methods for the hydrogenation and dehydrogenation of organic hydrogen carriers usually require high temperature and pressure conditions and external hydrogen supplies, which hinder their large-scale applications, as well as having certain safety risks. In this paper, a reversible electrochemical hydrogen storage system using quinoxaline as a hydrogen carrier was developed with potential for use at room temperature and atmospheric pressure. Experiments revealed that the hydrogenation conversion of quinoxaline reached 95% within 120 min at −0.20 V vs. RHE, and the dehydrogenation conversion of 1,2,3,4-tetrahydroquinoxaline reached 100% within 30 min at 1.30 V vs. RHE. This means that the system achieved quick and efficient reversible hydrogen storage. The Pd/NF dual-function electrode prepared by spontaneous redox reaction still showed high catalytic activity after 8 cycles, indicating its good long-term stability. The proton donor in the electrochemical hydrogenation process of quinoxaline was water, which completely eliminates the safety risk from the use of external hydrogen. This work provides a simple and reliable strategy for efficient hydrogen storage using nitrogen heterocyclic organics.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Gaojie Li,Kai Du,Xinxin Wang,Xiaochen Wang,Boao Chen,Chuangwen Qiu,Jiaqiang Xu
This study is attempted to improve the hydrogen sensing performance of SnO 2 based sensors by simultaneously employing two strategies of morphology control and noble metal loading. Therefore, SnO 2 ultrathin nanosheets with thickness not exceeding 3.5 nm were successfully synthesized by a hydrothermal method and then different content of Pd nanoparticles were uniformly loaded onto SnO 2 surface by in situ reduction with ascorbic acid . The gas sensing properties demonstrated that the introduction of Pd not only altered the selectivity of the SnO 2 sensor from ethanol to hydrogen, but also significantly improved the gas sensitivity and reduced the working temperature. And the optimal 1.0%Pd/SnO 2 sensor owned the highest sensitivity (75), fastest response-recovery property (21 s/13 s) to 20 ppm of hydrogen at 220 °C, and the actual detection limit is as low as 0.1 ppm. Furthermore, 1.0%Pd/SnO 2 sensor exhibited excellent repeatability, reproducibility and acceptable anti-interference of humidity. The DFT studies suggest that the physisorption of the hydrogen molecules on the surface of SnO 2 , but chemisorption on the surface of Pd/SnO 2 . The improved H 2 sensing performance of Pd/SnO 2 sensor attributes its ultrathin thickness of SnO 2 and catalytic dissociation of Pd to O 2 and H 2 .
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MOLECULES
·
2023
·Vol. 28
·期 12
·4731
·
IF 4.6
Ailing Li,Fuping Dong,Yuzhu Xiong
Nitrogen-rich porous organic polymers were fabricated through a nonreversible ring-opening reaction from polyamines and polyepoxides (PAEs). The epoxide groups reacted with both primary and secondary amines provided by the polyamines at different epoxide/amine ratios with polyethylene glycol as the solvent to form the porous materials. Fourier-transform infrared spectroscopy confirmed the occurrence of ring opening between the polyamines and polyepoxides. The porous structure of the materials was confirmed through N2adsorption–desorption data and scanning electron microscopy images. The polymers were found to possess both crystalline and noncrystalline structures, as evidenced by X-ray diffraction and high-resolution transmission electron microscopy (HR-TEM) results. The HR-TEM images revealed a thin, sheet-like layered structure with ordered orientations, and the lattice fringe spacing measured from these images was consistent with the interlayer of the PAEs. Additionally, the selected area electron diffraction pattern indicated that the PAEs contained a hexagonal crystal structure. The Pd catalyst was fabricated in situ onto the PAEs support by the NaBH₄ reduction of the Au precursor, and the size of the nano-Pd was about 6.9 nm. The high nitrogen content of the polymer backbone combined with Pd noble nanometals resulted in excellent catalytic performance in the reduction of 4-nitrophenol to 4-aminophenol.Keywords:porous organic polymer;amine–epoxy;ring opening;catalyst carrier
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Molecular Catalysis
·
2023
·
IF 4.6
Tianyun Cui,Yu Ling,Jipeng Meng,Ke Li,Changhai Liang,Chuang Li
Nowadays, the rational design of high-performance catalysts with desirable resistance to metal leaching has become the principal challenge in the hydrogenation of nitrile butadiene rubber. In the present work, the Pd-Pt bimetallic alloy nanocatalyst exhibits an outstanding hydrogenation degree of 99.0%, obviously higher than that of the conventional monometallic Pd/SiO 2 catalyst with the same Pd content (92.9%), accompanied by approximately 100% selectivity to C=C bonds. The results reveal that electron transfer from Pt to Pd confirms that the Pd species are in a rich-electron state, which boosts hydrogen activation and improves catalytic activity. Additionally, the incorporation of inactive Pt species promotes the formation of uniformly dispersed Pd-Pt alloy nanoparticles. The incorporation of inactive Pt species can enhance the metal-support interaction, reducing the residual metal content in hydrogenated nitrile butadiene rubber. The current research demonstrates a simple procedure for designing efficient bimetallic catalysts for the hydrogenation of unsaturated elastomer.
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CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Qiqi Lu,Xiu-Zhi Wei,Haiyong Wang,Qi zhang,Xinghua Zhang,Lungang Chen,Jianguo Liu,Longlong Ma
The selective hydrogenation of nitrile represents an atom-economical and reliable method to synthesize primary amine, a privileged compound in chemistry, biology, and medicine. However, this approach often displays severe selectivity issues, and additives or reducing agents are generally required to solve this problem. In this work, we aim to synthesize primary amine on a green catalytic system and probe into the catalytic mechanism of Pd-Ni interaction using benzonitrile (BN) as a model compound. The nitrile hydrogenation reaction was catalyzed by bimetallic Pd-Ni oxide nanospecies confined in Silicalite‑1 (S-1) zeolite using H 2 as hydrogen donor without any additive which was environmentally friendly and economic. A 92% yield of benzylamine (BA) was achieved on the [email protected] catalyst with a turnover number (TON) of 1667, and such BA yield was still maintained in upscaling experiment. Detailed characterizations shed light on the mechanism of the extraordinary performance of Pd-Ni oxide nanospecies on base-free nitrile hydrogenation.
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Advanced Science
·
2023
·
IF 15.1
Saijun Wang,Zaigang Zhou,Rui Hu,Mingyue Dong,Xiaobo Zhou,Siyan Ren,Yi Zhang,Chengxun Chen,Ruoyuan Huang,Man Zhu,Wanying Xie,Ling Han,Jianliang Shen,Congying Xie
At present, radiotherapy (RT) still acquires limited success in clinical due to the lessened DNA damage under hypoxia and acquired immune tolerance owing to the amplified programmed death ligand-1 (PD-L1) expression. Incredibly, intracellular PD-L1 expression depression is proven to better sensitize RT by inhibiting DNA damage repair. However, the disability of the clinically used antibodies in disrupting the extracellular PD-L1function still limits the effectiveness of radio-immunotherapy. Therefore, better PD-L1 regulation strategies are still urgently needed to better sensitize radio-immunotherapy. Hence, for this purpose, TPP-LND is synthesized by linking mitochondrial-targeted triphenylphosphine cations (TPP + ) to the antineoplastic agent lonidamine (LND), which significantly reduces the dose needed for LND to induce effective oxidative phosphorylation inhibition (2 vs 300 µ M ). Then, TPP-LND is wrapped with liposomes to form TPP-LND@Lip nanoparticles. By doing this, TPP-LND@Lip nanoparticles can sensitize RT by reversing the hypoxic microenvironment of tumors to generate more DNA damage and reducing the expression of PD-L1 via enhancing the adenosine 5′-monophosphate-activated protein kinase activation. As expected, these well-designed economical TPP-LND@Lip nanoparticles are more effective than conventional anti-PD-L1 antibodies to some extent.
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ACS Applied Nano Materials
·
2023
·
IF 5.9
Lulu Kong,DeZhu Chen,Xiaolong Zhang,Lin Zhou,Yongming Deng,Shaohua Wei
The growth of oxides on the surface of noble metals and the introduction of alloys are effective methods to enhance the catalytic activity of noble metals. However, the fabrication of noble metal oxides always involves harsh experimental conditions and the oxidation degree could not be controlled. Herein, a simple, fast, and controlled Pd oxidation method by mixing Hg2+ and Pd nanosheets (PdNSs) under mild conditions to form PdxHgy(PdO)z (PHOs) was reported, which consists of the Pd–Hg alloy and PdO. The density functional theory (DFT) calculation and experiment results proved that the Hg atom incorporation promotes the nearby Pd–Pd bond breaking, initiating a cascade of PdO generation. More precisely, 1 Hg atom incorporation induced ∼8 Pd atom oxidation, ensuring that the oxidation degree of Pd could be easily controlled by adjusting the ratio of Hg2+ and PdNS. As a peroxidase-mimicking nanozyme, the PHO affinity for its substrate could be 21.7- and 123.6-fold greater than that of the PdNS and the natural peroxidase (HRP), respectively. For the colorimetric immunoassay of carcinoembryonic antigen (CEA) detection, PHO has an ultralow detection limit of 1.33 pg mL–1, which is ∼8.6 and ∼282 times lower than that of the PdNS and the natural HRP, respectively.
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