Green Energy & Environment
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2020
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IF 6.395
Difan Li,Xiuge Zhao,Qingqing Zhou,Bingjie Ding,Anna Zheng,Qingpo Peng,Zhenshan Hou
Selective oxidation of glycerol provides a feasible route towards the sustainable synthesis of high value-added chemicals. Herein, the hydroxyapatite (HAP) supported palladium (Pd) species were fabricated by impregnation and subsequent calcination. The as-obtained heterogeneous Pd catalyst afforded not only excellent selectivity to glyceric acid (GLA) up to 90% with 59% conversion of glycerol but also good recyclability by using molecular oxygen as an oxidant under mild conditions. The characterization of catalysts indicated that both the surface basicity and Pd sites on the catalyst played a crucial role in promoting glycerol oxidation. Notably, it demonstrated that the presence of the vicinal hydroxyl group of glycerol molecule can assist the oxidation reaction via forming a coordination between the vicinal hydroxyl group and Ca 2+ sites on HAP-derived catalysts. In this catalytic process, the secondary hydroxyl of glycerol kept untouched and the primary hydroxyl of glycerol was converted into carboxyl group, while the Pd species acted as active centers for cooperatively promoting the subsequent oxidation to generate GLA. Additionally, this catalytic system can be extended widely for the oxidative conversion of other vicinal diols into the corresponding α-hydroxycarboxylic acids selectively. Isotope labeling experiment using H 2 18 O confirmed that H 2 O not only acted as solvent but also was involved in the catalytic cycles. On the basis of the results, a possible reaction mechanism has been proposed. The HAP-supported Pd catalytic system has been shown to serve as an effective approach for the upgrading of bio-derived vicinal diols to high value-added chemicals.
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COMPOSITES SCIENCE AND TECHNOLOGY
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2020
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IF 7.094
Junjun Huang,Chengmei Gui,Haodong Ma,Peng Li,Wangping Wu,Zhenming Chen
Electroless nickel plating provides a rapid and low-cost approach to prepare surface-metallization material, but complicated technology would increase cost and restrict its application. In this work, a new kind of Pd nanoparticle/polymer brush (Pd/ PB ) catalytic solution ( AS ) with a mixture of deionized water, ethanol, 3-aminopropyltriethoxysilane ( KH550 ), PdCl 2 solution was designed to modify and activate polyethylene terephthalate ( PET ) simultaneously. Pd nanoparticle could be adsorbed by PB with –NH 2 , Si–O–Si groups from hydrolyzed KH550. An activated layer with Pd/PB structure established on PET surface after coating AS solution. The generated Ag/PB that served as seed to catalyze the electroless nickel plating. As a result, a facile route for electroless nickel plating was achieved. The maximum effective thickness, rupture work and adhesion of Ni-plated coating were about 0.8 μm, 0.4 J/m 2 , and 5B, respectively, and it maintained considerable conductivity even after 1000 times of cyclical bending. This dependable technology has great potential application in the preparation of metal-polymer material.
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Arabian Journal of Chemistry
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2020
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IF 4.762
Zhen Huang,Chen Wang,Jiling Zhao,Shixing Wang,Yang Zhou,Libo Zhang
A new adsorbent was successfully fabricated by chemically linking pyromellitic acid onto a zirconium-based metal-organic framework composite for selective adsorption of Pd(II) from an aqueous solution. The adsorbent was characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller equation and scanning electron microscope. The adsorption capacity, selectivity and repeatability of the adsorbent were tested by batch experiments. The optimum pH was 2.0, and the maximum adsorption capacity at room temperature was 226.1 mg/g. In the kinetic experiments, the adsorption process achieved equilibrium within 5 h and generally conformed to the quasi-second kinetics and Freundlich isotherm model. The N-H and O H groups on the adsorbent interacted with Pd(II) by electrostatic and coordination action. The adsorbent maintained excellent adsorption capacity after at least 5 cycles. At the same time, the selectivity of the adsorbent in aqueous solution is excellent from interfering ions. Therefore, the new adsorbent will have an obvious application prospect on the recovery of palladium.
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Catalysis Science & Technology
·
2020
·Vol. 10
·期 12
·4099-4108
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IF 5.721
Ting Qu,Qiang Tan,Liting Liu,Shengwu Guo,Sai Li,Yongning Liu
The wide application of direct ethanol fuel cells (DEFCs) was blocked by the sluggish catalytic activity of catalysts, insufficient ionic conductivity of the polymer electrolyte membrane (PEM), and ethanol crossover issues. To overcome the problems mentioned above, a novel DEFC system with a polymer fiber membrane (PFM) and nonplatinum catalysts is proposed. In this system, the performance of the anode catalyst Pd/C is significantly promoted by homogeneous Ni-doped SnO2 nanoparticles, and the inexpensive permeable PFM is used as a substitute for the PEM. Due to the remarkable catalytic activity and the optimized resistance, the PFM-based DEFC exhibits encouraging performance, which can afford a peak power density of 47.4 mW cm−2 with a porous NiCo2O4 cathode catalyst. Moreover, it can operate continuously for 100 h with only 4.56% drop in electrical output. Therefore, this study provides a very effective strategy for optimizing DEFCs with low cost and high performance.
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RSC Advances
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2020
·Vol. 10
·期 26
·15091-15097
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IF 3.119
Lei Ge,Meng Zhang,Ran Wang,Na Li,Lexin Zhang,Shufeng Liu,Tifeng Jiao
In this study, natural polymer material chitosan (CS) and graphene oxide (GO) with large specific surface area were used to prepare a new CS/RGO-based composite hydrogel by using glutaraldehyde (GA) as cross-linking agent. In addition, a CS/GA/RGO/Pd composite hydrogel was prepared by loading palladium nanoparticles (Pd NPs). The morphologies and microstructures of the prepared hydrogels were characterized by SEM, TEM, XRD, TG, and BET. The catalytic performance of the CS/GA/RGO/Pd composite hydrogel was analyzed, and the experimental results showed that the CS/GA/RGO/Pd composite hydrogel had good catalytic performance for degradation of p-nitrophenol (4-NP) and o-nitroaniline (2-NA). Therefore, this study has potential application prospect in wastewater treatment and provides new information for composite hydrogel design.
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PubMed
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SOLID STATE SCIENCES
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2020
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IF 2.434
Jian Lv,Qingran Wang,Peng Chen,Heng Liu,Zhongmin Su,Jianxun Zhao,Wanqiang Liu,Jianhua Hou,Shang Gao
The Co 2 B alloy is synthesized by high temperature solid phase process. 5 wt% Pd is added to the Co 2 B alloy by ball milling at different milling time in order to enhance discharge performance of the raw alloy. The phase structure and surface morphology of these alloys is characterized by XRD and SEM. The discharge capacities of the alloy milled for 10 min and 30 min are higher than that of the raw alloy. However, the discharge capacity of the alloy milled for 1 h is lower than that of the raw alloy. The result of linear polarization and EIS shows that proper milling time and uniform distribution of palladium on the alloy surface can make the alloy electrode have excellent discharge capacity. Ball milling at appropriate time can make the palladium on the alloy surface uniformly distributed and the alloy particles do not aggregate, which increases the charge-transfer reaction rate and discharge capacity. The experimental results prove that the addition of palladium and proper ball milling can effectively improve the electrochemical hydrogen storage capacity of the Co 2 B alloy.
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ACS Applied Materials & Interfaces
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2020
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IF 8.758
Yanyan Wang,Jiaping Liao,Zunyuan Xie,Kan Zhang,Ya Wu,Ping Zuo,Weiqiang Zhang,Jiyang Li,Ziwei Gao
Supported palladium catalysts have attracted significant attention for use in cross-coupling reactions due to their recyclability. However, the inevitable progressive loss of Pd that occurs in the catalytic process deactivates the catalysts, which hinders their sustainable application. Herein, we report a zeolite-enhanced sustainable Pd catalyst for C–C cross-coupling reactions. Zeolite does a good job of acting as a sink for Pd2+ ions. This catalyst exhibits an excellent homogeneous catalytic performance by releasing Pd species from zeolite. In addition, the Pd2+ ions were successfully recaptured in a controlled catalytic system by combining the uniform microporous structure and good adsorption features of zeolite. The release/capture mechanism of the Pd species guaranteed the high loading and high dispersion of Pd on the recycled catalyst. The 0.84%Pd@USY catalysts were reused at least 10 times in water without an appreciable reduction in activity. This study presents a new perspective toward the design of a highly efficient and sustainable supported metal catalyst.
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Nano Research
·
2021
·Vol. 15
·期 2
·1288-1294
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IF 8.897
Guo Xiaoyun,Hu Zheng,Lv Jianxin,Li Hui,Zhang Qinghua,Gu Lin,Zhou Wei,Zhang Jiangwei,Hu Shi
Metal catalysts play an important role in the catalytic electrochemical processes and optimization of their performance is usually achieved through alloying with other metal atoms. Doping with interstitial hydrogen atoms is a special but effective way to regulate the electronic structure of host catalysts. Herein we demonstrate the intermixing of Pd and Rh atoms during the hydrogen-doping process of Pd@Rh core-shell nanocubes, forming an alloyed surface in Pd@Rh-H. The catalysts show enhanced performance in electrocatalytic methanol oxidation, as compared to commercial Pt/C and are even better than PdH@Rh core-shell nanocubes. The small structural differences between the two hydride catalysts are revealed by X-ray electron spectroscopy and pair distribution function analysis of electron diffraction. The theoretical calculation results show that Rh in Pd@Rh-H contains more negative charges than Rh in PdH@Rh, indicating more effective charge transfer in Pd@Rh-H. The d-band center ( ε d ) of the Rh site in Pd@Rh-H shifts up, and the synergy between Rh and Pd optimizes the binding energy of CO and OH, inducing preferential catalytic activity. Our work provides guidance for the synthesis of high-performance catalysts by doping with interstitial atoms, which may provide a new strategy to fine-tune the electronic structure of other bimetallic nanoparticles.
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HYDROMETALLURGY
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2021
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IF 4.156
Wei Shi,Ying Hu,Quan Li,Tianqi Lan,Xueyan Zhang,Jing Cao
Unlike sulfur-containing extractants, extraction efficiency of extractants containing N atoms is often affected by the concentration of H + , but strong affinity of sulfur to Pd(II) may cause stripping process not smoothly. Since sulfur atom conjugated with C C decreases electron cloud density on S atom, a novel polymer extractant containing vinyl sulfide motifs (Poly-EDDYPF) was designed and prepared in this paper, the investigation of this acid resistant extractant shows that the polymer has high extraction efficiency of Pd(II) over 99% with nicely acid resistant. The loading experiment shows that the capacity of Pd(II) of Poly-EDDYPF is up to 268 mg/g. Nearly 95.6% Pd(II) in loaded organic phase could be easily stripped using acid thiourea solution (1 mol/L HCl + 0.1 mol/L thiourea) and the organic phrase could be reused at least 5 cycles without significant decrease of the extraction efficiency. The optimized conditions for the extraction process are given: [HCl] =1 mol/L, contact time = 20 min, amount of extractant =0.7 g/L, O/A ratio = 1/1. H + concentration and Cl – concentration exhibit practically no effect on extraction efficiency.
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Biomass Conversion and Biorefinery
·
2021
·Vol. 13
·期 12
·10701-10710
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IF 4.987
Zeng Qin,Du Zhenyu,Luo Ligang
In this study, different bimetallic (Ru, Pd, and Pt) catalysts over a variety of supports (activity carbon, γ-Al 2 O 3 , TiO 2 , HZSM-5) were employed to improve the kraft lignin depolymerization process using isopropanol as in situ hydrogen source. The effect of catalysts was firstly investigated, which suggested that 1wt%Ru-1wt% Pd/HZSM-5 promoted the hydrogenolysis and hydrodeoxygenation effect on conversion of kraft lignin (95.86 wt%) and the selectivity of aliphatic alcohol (26.92 wt%) and hydrocarbon monomers (35.73 wt%), respectively. The effect of temperature and reaction time were also discussed, which indicated that the high temperature (250 to 310 °C) promoted the hydrogenolysis process; while the temperature is higher than 310 °C, the repolymerization process was appeared, leading to the decreasing yield of total monomers. For the influence of reaction time, it was noted that the optimal reaction time to acquired high yield and selectivity of aliphatic alcohol and hydrocarbon monomer was 120 min. It was also conducted FTIR and 2D HSQC NMR analysis to understand the effective depolymerization of the major linkages with attacked by the Ru-Pd/HZSM-5 catalyst, which was corresponding with the results with GC–MS. Graphical abstract
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JOURNAL OF ORGANIC CHEMISTRY
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2021
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IF 4.354
Junhua Kong,Zhi-Jiang Jiang,Jiayuan Xu,Yan Li,Hong Cao,Yanan Ding,Bencan Tang,Jia Chen,Zhanghua Gao
A practical and scalable ortho-selective deuteration of aromatic aldehydes was accomplished by Pd-catalyzed hydrogen isotope exchange with deuterium oxide as an inexpensive deuterium source. The use of tert-leucine as a transient directing group facilitates the exchange, affording a wide range of ortho-deuterated aromatic aldehydes with deuterium incorporation up to 97%. The control experiments suggest that the addition of silver trifluoroacetate resists the unexpected reduction of Pd(II), while the theoretical study indicates a rapid reversible concerted metalation–deprotonation process.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zichen Zhang,Hengjun Gai,Qun Li,Bingxiao Feng,Meng Xiao,Tingting Huang,Hongbing Song
In this work, N-rich ionic liquid based on 1,3,5-triimidazole triazine was used to construct poly(ionic liquid) (PIL) through free radical polymerization, and support palladium nanoparticles (Pd NPs), which were used in the catalytic hydrogenation of nitrobenzene. The resulting N-rich PIL had a good dispersion effect and ultrafine Pd NPs as shown by SEM and TEM, thereby significantly enhancing the stability of the loaded metal NPs. The XPS results indicated that the metal-support interaction improved the catalytic performance of the catalyst. In particular, the effects of different anions (Tf 2 N - , PF 6 - , and Cl - ) on the PILs were investigated, and the results showed that the Tf 2 N anion exhibited the best catalytic effect on the hydrogenation of nitrobenzene. Furthermore, density functional theory calculation confirmed that anions played a key role in activating the substrate in the hydrogenation of nitrobenzene. The corresponding results were consistent with the experimental results, which provided reference and research for the application of PILs in the future.
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