查找使用阿拉丁产品的科研文献

Adsorption of Cr (VI) onto Attapulgite/UiO-66-NH2 Composites from Aqueous Solution

Peiyi Bao,Haiying Du,Xiangning Xu,Junya Li,Yao Wu,Shaojiang Zhou,Lingyun Li,Ningfei Lei

Effective toluene adsorption over defective UiO-66-NH2: An experimental and computational exploration

Xiaoyu Shi,Xiaodong Zhang,Fukun Bi,Zenghui Zheng,Lijun Sheng,Jingcheng Xu,Zhong Wang,Yiqiong Yang

In this thesis, defective UiO-66-NH 2 using cetyltrimethylammonium bromide (CTAB) as a template was successfully synthesized. The toluene adsorption-desorption properties were studied using breakthrough experiments and temperature programmed desorption (TPD). Modified UiO-66-NH 2 showed a high toluene increase due to the increased specific surface area and total pore volume and extra accessible adsorption sites generated by defects. Additionally, adsorption mechanisms were discussed at micro and molecule levels in light of density functional theory (DFT) calculations. By calculation, the amino hydrogen bonding gave rise to a higher toluene adsorption over UiO-66-NH 2 . In terms of the modified UiO-66-NH 2 with the most deficiencies, synergistic effects among π-π, -NH 2 , OH-CH 3 and OH-π hydrogen bonding strength also significantly intensified toluene adsorption. Furthermore, it could be noted that the OH-π interaction was stronger than the two bonded μ 3 -OH mechanisms. Notably, TPD and binding energies (BEs) depicted that defective UiO-66-NH 2 had a weaker toluene affinity than did UiO-66-NH 2 . Thus, gas toluene was easy to desorb with defective UiO-66-NH 2 at 298 K under atmospheric pressure. Finally, the repetitive regeneration experiment showed that the reproducibility of the materials was excellent.

TiO2-UiO-66-NH2 nanocomposites as efficient photocatalysts for the oxidation of VOCs

Jinhui Zhang,Yun Hu,Junxian Qin,Zhenxiang Yang,Mingli Fu

TiO 2 -UiO-66-NH 2 nanocomposites with different mass ratios were successfully prepared by a simple solvent evaporation method for photocatalytic oxidation of toluene and acetaldehyde under UV light condition. The experimental results revealed that the nanocomposites exhibited superior removal efficiency for toluene and acetaldehyde than the pure TiO 2 , UiO-66-NH 2 and other TiO 2 -based porous materials during a 720 min of long-term evaluation under flowing conditions. The as-prepared 75TiO 2 -25UN nanocompoites exhibited the highest photocatalytic activity and CO 2 selectivity. The conversion of 75TiO 2 -25UN for toluene and acetaldehyde were 72.7% and 70.74% respectively, which was about 9.7 and 10.5 times higher than that of UiO-66-NH 2 , respectively. In addition, the CO 2 production of 75TiO 2 -25UN for toluene and acetaldehyde were 21.1 and 14.3 times higher than that of pure UiO-66-NH 2 , respectively. N 2 adsorption-desorption and SEM results revealed that high surface area could enhance the dispersion of TiO 2 and efficient contact to the VOCs. Photoelectrochemical properties indicated that photoinduced carriers can be efficiently separated and transferred via the interface of two components. The outstanding deactivation resistance was achieved over 75TiO 2 -25UN sample due to the efficient charge transfer and oxygen-rich condition. The possible mechanism of VOCs oxidation was proposed based on radical scavenger experiments, which proved that O 2 − and h + are the main active species. This work clearly demonstrated that MOF-based composite can be used as efficient photocatalysts for the application of VOCs oxidation.

Temperature modulation of defects in NH2-UiO-66(Zr) for photocatalytic CO2 reduction

Yanghe Fu,Jieyu Wu,Rongfei Du,Ke Guo,Rui Ma,Fumin Zhang,Weidong Zhu,Maohong Fan

Defect engineering can be a promising approach to improve the photocatalytic performance of metal–organic frameworks (MOFs). Herein, a series of defective NH2-UiO-66(Zr) materials were synthesized via simply controlling the synthesis temperature, with concentrated HCl as the modulator and then these as-prepared samples were used to systematically investigate the effects of their structural defects on photocatalytic CO2 reduction. Remarkably, these MOFs with defects exhibit significantly enhanced activities in photocatalytic CO2 reduction, compared with the material without defects. The defect engineering creates active binding sites and more open frameworks in the MOF, and thus facilitates the photo-induced charge transfer and restrains the recombination of photo-generated charges efficiently. The current work provides an instructive approach to improve the photocatalytic efficiency by taking advantage of the structural defects in MOFs, and could also inspire more work on the design of advanced defective MOFs.

Biomimetic photocatalyst Ce/TCPP-UiO-66-NH2 for NADH regeneration and CO2 activation

Hao Guo,Likun Luan,Jinde Cai,Xiuling Ji,Haijun Yu,Yuhong Huang

CO 2 activation and conversion by enzymes to produce value-added multi-carbon compounds under mild conditions show significant impact on carbon neutrality. However, the enzyme co-factor NADH is expensive and the regeneration is still challenging for the enzyme reaction process. Inspired by natural photosynthesis, this study successfully developed a biomimetic photocatalyst Ce/TCPP-UiO-66-NH 2 (TCPP: meso-tetrakis (4-carboxyphenyl) porphine) for NADH regeneration and CO 2 activation. Structure analysis and spectra showed that the co-doping of Ce and TCPP reduced the band gap width of UiO-66-NH 2 , improved the separation efficiency of photo-generated carriers, and endowed it with excellent photocatalytic performance. The synthesized biomimetic photocatalyst Ce/TCPP-UiO-66-NH 2 was then applied for NADH regeneration. The regeneration efficiency of NADH can reach up to 95 % after 3 h of light reaction, which was about 1.6 times higher than that of the control group. Ultra-fast femtosecond time-resolved transient absorption (fs-TA) showed that Ce/TCPP-UiO-66-NH 2 possessed the shortest average decay time ( τ ¯ $\overline{\tau }$  = 1.12 ps), indicating shorter average life-time of carriers after Ce doping, thus suppressing hole-electron recombination. Finally, the key enzyme formate dehydrogenase (FDHPa) for CO 2 activation was immobilized on the membrane, combining with light regeneration of NADH for CO 2 production to formate. The formate yield (3.1 mM) was 16 times higher than that of the control group (0.19 mM). This work provided an effective strategy and efficient photocatalyst for the biomimetic photocatalytic activation of CO 2 to formate, which is an indispensable bridge for the further high-valuable C n compounds production by biocatalysis.

Flexible UiO-67(Zr)@cyclodextrin-based nanofiber membrane for efficient removal of ibuprofen

Shushu Jia,Ping Lin,Yue Li,Yakun Teng,Jing Wang,Tianyi Yang,Lijuan Li,Ce Wang,Xiang Li

The efficient removal of pharmaceutical pollutants in groundwater has become an urgent issue in sewage treatment. β-cyclodextrin (β-CD), a polysaccharide and rich in raw materials, has broad applications in adsorption and separation due to its host–guest interaction with many molecules. In this paper, a flexible and water-insoluble UiO-67(Zr)-modified cyclodextrin-based nanofiber membrane (UiO-67@β-CD-NP) was synthesized via a combination of electrospinning and solvothermal methods. By virtue of the synergetic adsorption effect of cyclodextrin and MOFs, the UiO-67@β-CD-NP shows excellent performance for ibuprofen (IBP) removal. The adsorption of IBP onto UiO-67@β-CD-NP was well-fitted with the pseudo-second-order kinetic model and Freundlich isothermal model, yielding an adsorption capacity of 226.24 mg/g. Furthermore, the UiO-67@β-CD-NP nanofibers demonstrate a high removal rate of 100 % and exhibit good regenerability in dynamic adsorption experiments. After the filtration of UiO-67@β-CD-NP, the chemical oxygen demand (COD) concentration of IBP has evidently reduced below the discharge standard of pharmaceutical sewage. This study provides a simple and novel strategy for preparing low-cost and high-performance composite nanofiber membrane incorporating cyclodextrin and MOFs. This membrane holds great potential as a candidate for adsorption applications in practical pharmaceutical sewage treatment.

Au Nanoparticle-Loaded UiO-66 Metal–Organic Framework for Efficient Photocatalytic N2 Fixation

Zehui Zhao,Guangmin Ren,Xiangchao Meng,Zizhen Li

In order to achieve efficient photocatalytic N2reduction activity for ammonia synthesis, a photochemical strategy was used in this work. UiO-66 was prepared through the solvothermal method and further loaded with Au nanoparticles (Au NPs) onto the UiO-66 (Zr) framework. The experimental results verified that there were metal–support interactions between Au NPs and UiO-66; this could facilitate charge transfer among Au NPs and UiO-66, which was beneficial to enhance the photocatalytic activity. The best N2fixation effect of Au/UiO-66 with a loading of 1.5 wt% was tested, with a photocatalytic yield of ammonia of 66.28 μmol g−1h−1while maintaining good stability. The present work provides a novel approach to enhancing photocatalytic N2fixation activity by loading NPs onto UiO-66.

Enhanced adsorption of dyes by functionalized UiO-66 nanoparticles: Adsorption properties and mechanisms

Yongtong Lei,Jinglong Zhao,Haiming Song,Fanhang Yang,Luli Shen,Lijing Zhu,Zhixiang Zeng,Xiaocheng Li,Gang Wang

UiO-66-based metal-organic framework (MOF) materials are a class of porous crystalline materials consisting of Zr metal clusters compounded with organic ligands of terephthalic acid group. In this study, functionalized UiO-66-X ( X =H , NH 2 , (COOH) 2 ) nanoparticles were synthesized. The morphology of UiO-66-X nanoparticles were characterized by SEM, while the crystal structure was analyzed using XRD and TGA . Chemical composition of UiO-66-X nanoparticles were analyzed through TFIR and XPS . The adsorption capacities of UiO-66-X nanoparticles for anionic dye of Congo red (CR), and cationic dyes of methylene blue (MB) and rhodamine B (Rh B) dyes were evaluated. Furthermore, the adsorption mechanisms of UiO-66-X nanoparticles for dyes were analyzed and summarized. Results showed that the adsorption capacities of UiO-66 and UiO-66-NH 2 on CR were 93.05 mg/g and 94.20 mg/g, respectively. In particular, the adsorption capacities of UiO-66-(COOH) 2 on MB and Rh B were significantly increased with the adsorption capacities of 80.66 mg/g and 72.64 mg/g, respectively. Due to the strong π-π effect and hydrogen bonding interactions between UiO-66 and CR dyes. UiO-66-NH 2 has stronger hydrophilicity and has electrostatic interactions , Lewis acid-base interactions and hydrogen bonds with CR. The abundant -COOH groups and higher negative Zeta potential (-23.43 mV) in UiO-66-(COOH) 2 led to strong electrostatic interactions and Lewis acid-base interactions with the cationic dyes MB and Rh B. Therefore, the adsorption performance of UiO-66-(COOH) 2 on cationic dyes was improved.

Adsorption of diclofenac from aqueous solution using UiO-66-type metal-organic frameworks

Shuting Zhuang,Rong Cheng,Jianlong Wang

UiO-66 type metal organic frameworks (MOFs), including UiO-66 and UiO-66-NH 2 , were synthesized, characterized, and applied for the adsorptive removal of diclofenac (DCF) from aqueous solutions. The effect of synthetic conditions (e.g., different linkers and activation temperatures) and adsorptive conditions (e.g., contact time, initial concentration, temperature, and pH) on DCF removal was examined. UiO-66-NH 2 showed a higher adsorption capacity than UiO-66, and the increase of activation temperature can improve the adsorption capacity of UiO-66-NH 2 towards DCF. The adsorption of DCF by UiO-66-NH 2 was endothermic and almost not affected by pH in the range of 4.8–7.7. The adsorption of DCF onto UiO-66 type MOFs conformed to the pseud second-order kinetic model and the Langmuir isothermal model, with adsorption capacity of 357 mg g −1 for UiO-66 and 555 mg g −1 for UiO-66-NH 2 . Electrostatic interaction and H-bonding possibly played a vital role for DCF adsorption. The as-prepared UiO-66 type MOFs were efficient adsorbent for DCF removal from aqueous solution.

Synthesis and Luminescence Properties of CsPbX3@Uio-67 Composites toward Stable Photoluminescence Convertors

Diwei Zhang,Jing Zhao,Quanlin Liu,Zhiguo Xia

All-inorganic halide perovskite (CsPbX3, X = Cl, Br, or I) nanocrystals (NCs) have been widely studied due to their outstanding optoelectronic properties. However, some inevitable factors like light, heat, and moisture affected the stability of CsPbX3 NCs and further limited their practical application. In this work, the stability of all-inorganic halide perovskite NCs can be improved by integrating them in the stable Zr-based metal–organic frameworks (Uio-67). Compared to pristine perovskite NCs, typical CsPbBr3@Uio-67 composites display a stable photoluminescence property that can be maintained for 30 days under ambient atmospheric conditions. Due to the proposed confinement effects of CsPbX3 NCs coordinated with the pore structures of Uio-67, the related structural model of CsPbX3@Uio-67 composites was elucidated. White LED device was further fabricated by combining CsPbBr3@Uio-67 composites and commercial K2SiF6:Mn4+ red phosphors with a blue-emitting chip, which demonstrated a wide color gamut (138% of National Television Standards Committee color space). The strategy on encapsulation of CsPbX3 NCs into Uio-67 will open up a stable platform for optoelectronic applications.

UiO-66-NO2 as an Oxygen “Pump” for Enhancing Oxygen Reduction Reaction Performance

Shanshan Zeng,Fucong Lyu,Ligang Sun,Yawen Zhan,Fei-Xiang Ma,Jian Lu,Yang Yang Li

In this work, UiO-66-based metal–organic frameworks are investigated as an oxygen reduction reaction (ORR) catalyst for the first time. UiO-66-NO2 is solvothermally grown on the surface of cobalt phthalocyanine-anchored carbon nanotube (CoCNT) surface, serving as an oxygen “pump” to accelerate the oxygen reduction reaction (ORR). The UiO-66-NO2-attached CoCNT (UiO-66-NO2@CoCNT) exhibits superior electrochemical catalytic properties, exceeding the state-of-the-art commercial 20% Pt/C catalyst with more positive half-wave potential (15 mV difference, at 1600 rpm), better stability (no significant degradation for UiO-66-NO2@CoCNT vs 19% degradation for 20% Pt/C after 25 000 s), and higher methanol tolerance. When assembled in a flexible zinc–air battery, the UiO-66-NO2@CoCNT remains a competitive alternative to commercial 20% Pt/C catalyst with comparable power density and excellent flexibility, suggesting its potential in wearable electronic devices. The outstanding performance of UiO-66-NO2@CoCNT composite is closely related to the synergetic effect among the three components: CNT as a conductive backbone, cobalt phthalocyanines as the oxygen reduction catalytic active site, and UiO-66-NO2 as an ideal oxygen adsorption pump (the oxygen diffusion rate is 4.8 times that of 20% Pt/C and 17.7 times that of CoCNT). The synergy between the three components facilitates oxygen adsorption, transfer of adsorbed oxygen molecules, oxygen reduction, and electron conduction.

Lightweight UiO-66/cellulose aerogels constructed through self-crosslinking strategy for adsorption applications

Zhongguo Wang,Lian Song,Yaquan Wang,Xiong-Fei Zhang,Dandan Hao,Yi Feng,Jianfeng Yao

Composite UiO-66/nanocellulose aerogels with hierarchical pores and low density were prepared through a self-crosslinking method. The nanocellulose acted as the structural skeleton supporting and dispersing the UiO-66 particles. The micropore and accessibility of UiO-66 were well-preserved, making the composite aerogels ideal sorbents for water purification. The composite aerogels demonstrated high adsorption ability towards both anionic methyl orange (71.7 mg g −1 ) and cationic methylene blue (51.8 mg g −1 ). This work holds a promise to rational design and fabrication of MOF monoliths through group linkage.