查找使用阿拉丁产品的科研文献

Highly Ethylene-Selective Electroreduction CO2 Over Cu Phosphate Nanostructures with Tunable Morphology

Zhang Li,Men Yong,Wu Bin,Feng Yuanfen,Song Chao,Liu Shuang,Wang Jinguo,An Wei,Magkoev Tamerlan T.

Highly selective production of valuable ethylene from electrocatalytic CO 2 reduction reaction (ECO 2 RR) is particularly desirable yet challenging. Morphology engineering is an effective strategy for catalyst design, which can adjust the electronic structure of catalyst surface, change the adsorption behavior of critical reaction intermediates over catalyst surface, and thus regulate the activity of electrocatalytic CO 2 reduction reaction. In this work, we prepared copper phosphate catalysts with different morphologies and tested their catalytic activity for the ECO 2 RR in the flow cell. Compared with irregular flocculent aggregates, copper phosphate nanospheres exhibit a high and stable ethylene Faradaic efficiency of 47% with high current density of 350 mA·cm − 2 , which is higher than the 200 mA·cm − 2 required for industrial applications. The catalysts were extensively characterized by SEM, EDS, XRD, ICP-OES, XPS, BET and CO-TPD. Combining the characterization results and activity data, we found that the superior spherical morphology of copper phosphate can increase the electron density around Cu, stabilize the Cu + species on the surface through the electron transfer between P and Cu, and adjust the adsorption strength of CO intermediates (*CO) to enhance the productivity of C 2+ products. This work provides new insights into catalyst design for highly efficient C 2 H 4 production from the electrocatalytic CO 2 reduction reaction by tuning morphologies of Cu-based catalysts.

Synergistic trimetallic Ni–Cu–Sn catalysts for efficient selective hydrogenation of phenylacetylene

Wei Chen,Huawu Xu,Xiaoling Ma,Lin Qi,Zhiming Zhou

Selective hydrogenation of phenylacetylene is the most effective way to remove a small amount of phenylacetylene from styrene, but it is still a challenge to develop catalysts with high activity and selectivity. Herein, a series of non-precious bimetallic Ni 3 M/SiO 2 (M = Zn, Sn, Cd, Fe, Co, Cu, or Mo) and trimetallic Ni 3 Cu–Sn/SiO 2 catalysts were prepared and applied to selective hydrogenation of phenylacetylene. A trade-off between activity and selectivity was observed on Ni 3 M/SiO 2 , where Ni 3 Cu/SiO 2 showed the best hydrogenation activity because of the hydrogen spillover effect of the Ni–Cu alloy, while Ni 3 Sn/SiO 2 exhibited the highest selectivity to styrene due to the active-site isolation effect of the Ni–Sn alloy. Impressively, trimetallic Ni 3 Cu–Sn/SiO 2 offered superior catalytic performance (94 % styrene selectivity at >99 % phenylacetylene conversion) as compared to bimetallic catalysts, owing to the synergistic effect among Ni, Cu, and Sn. In the case of Cu and Sn co-doping, the hydrogen spillover on the Ni–Cu alloy was deeply suppressed by Sn, which enabled an effective modification of the geometric and electronic structures of Ni to favor styrene desorption. The hydrogenation activity of Ni 3 CuSn 0.3 /SiO 2 can be readily enhanced by increasing the metal loading and further improved by elevating the reaction temperature and pressure, but meanwhile the high selectivity is little affected. This work demonstrates a multi-metal synergistic strategy to break the activity–selectivity trade-off of Ni-based bimetallic catalysts in the selective hydrogenation of alkynes.

Photo-Tuned Cu/Cu2O/CdS/PPy Heterojunctions for Hg2+ Sensing in Seawater

Minggang Zhao,Zhensen Liang,Ming Li,Hongzhi Cui,Ye Ma

Combustion process of a promising catalyst [Cu(Salen)] for HMX-CMDB propellants

Wenzhe Ma,Yanjing Yang,Yuxin Jia,Dongxiao Fu,Fengqi Zhao,Kangzhen Xu

Metal organic complexes are regarded as a series of promising combustion catalysts for solid rocket propellants. Their effects on the combustion performance of propellants are closely related to the reaction mechanism. Here, the metal–organic complex Cu(Salen) was investigated as a candidate material for the combustion catalyst of the HMX-added composite modified double-base propellant (HMX-CMDB). The combustion performance of the propellant was found to be evidently enhanced in the presence of Cu(Salen) compared with the propellant samples containing Benzoic-Cu or without catalyst. The addition of Cu(Salen) can improve the burning rate and combustion efficiency of the propellant – and greatly reduce the burning rate pressure index. Analysis shows that the addition of Cu(Salen) can increase the combustion area, flame brightness and combustion surface uniformity of the propellant to a higher degree. The sample can spray more beams of bright filaments on the flat combustion section, and the amount of gas generated by decomposition also greatly increases. In addition, Cu(Salen) shows amazing advantages in improving the surface of the propellant and the temperature gradient of the combustion flame.

CO2 Cycloaddition under Ambient Conditions over Cu–Fe Bimetallic Metal–Organic Frameworks

Hua-Qing Yin,Ming-Yang Cui,Hao Wang,Yuan-Zhao Peng,Jia Chen,Tong-Bu Lu,Zhi-Ming Zhang

Carbon dioxide cycloaddition into fine chemicals is prospective technology to solve energy crisis and environmental issues. However, high temperature and pressure are usually required in the conventional cycloaddition reactions of CO2 with epoxides. Moreover, metal active sites play a vital role in the CO2 cycloaddition, but it is still unclear. Herein, we select the isostructural MOF-919-Cu-Fe and MOF-919-Cu-Al as models to promote the performance and clarify the effects of metal type on the CO2 cycloaddition. The MOF-919-Cu-Fe with exposed Fe and Cu Lewis acid sites reaches the CO2 cycloaddition with over 99.9% conversion and over 99.9% selectivity at room temperature and a 1 bar CO2 atmosphere, 3.0- and 52.6-fold higher than those of the MOF-919-Cu-Al with Al and Cu sites (33.8%) and the 1H-pyrazole-4-carboxylic acid, Fe, and Cu mixed system (1.9%), respectively. The proposed mechanism demonstrated that the exposed Fe3+ sites facilitate the ring opening of epoxide and CO2 activation to boost the CO2 cycloaddition reaction. This work provides a new insight to tune the catalytic sites of MOFs to achieve high performance for CO2 fixation.

Defect-rich Cu@CuTCNQ composites for enhanced electrocatalytic nitrate reduction to ammonia

Na Zhou,Jiazhi Wang,Ning Zhang,Zhi Wang,Hengguo Wang,Gang Huang,Di Bao,Haixia Zhong,Xinbo Zhang

Electrochemical conversion of nitrate (NO 3 − ) pollutants into chemical feedstock and fuel ammonia (NH 3 ) can contribute to sustainable mitigation of the current severe energy and environmental crises. However, the electrocatalytic NO 3 − reduction to NH 3 (NRA) involves a sluggish multielectron and proton transfer process that competes with the hydrogen evolution reaction (HER) in aqueous media, imposing great challenges in developing highly selective catalysts for NRA. In this study, we developed a copper and copper-tetracyanoquinodimethane composite catalyst (Cu@CuTCNQ), which possesses a high density of copper vacancy defects. This catalyst has been proven to be efficient for NRA through an in situ electrochemical reconstruction method. The structural evolution of CuTCNQ during NRA was investigated by in situ Raman spectroscopy, which indicated an accelerated charge transfer from the CuTCNQ substrate to the derived Cu, which facilitated the adsorption activation of NO 3 − . The obtained Cu@CuTCNQ exhibited an excellent catalytic performance for NRA, with a Faradaic efficiency of 96.4% and productivity of 144.8 μmol h −1 cm −2 at −0.6 V vs . a reversible hydrogen electrode, superior to Cu nanoparticle counterparts and most Cu-based catalysts. Cu vacancy defects and sufficient interfacial charge transfer synergistically optimize the charge distribution of Cu active sites, reduce the energy barrier for NO 3 − adsorption, and promote deoxidation and hydrogenation processes, thus enhancing NRA and selectivity.

Adsorptive desulfurization using Cu+ modified UiO-66(Zr) via ethanol vapor reduction

Yan Yin,Yueyang Xu,Konglu Guo,Peng Zhang,Yongping Zeng

Adsorptive desulfurization is one of the alternative technologies for the effective removal of sulfides from fuels. Functionalization of metal-organic frameworks (MOFs) with Cu + is extremely desirable for adsorption separation via π-complexation interaction with adsorbed molecules. Here we report that Cu + cation is significant and highly effective for adsorption desulfurization in a new type of Cu + - modified UiO-66(Zr). First, Cu 2+ was introduced via ion-exchange with H + of UiO-66-SO 3 H. Then, Cu + cation was obtained from the reduction of Cu 2+ by using vapor-induced reduction, in which vapors of reducing agents diffuse into the pores of MOFs at a lower temperature. The resulted UiO-66-SO 3 Cu(I)− 0.15 has a better adsorption capacity for thiophene compared to pure UiO-66. In the presence of toluene, the UiO-66-SO 3 Cu(I)− 0.15 also exhibits high adsorption capacity for thiophene. After recycling four times, UiO-66-SO 3 Cu(I)− 0.15 still remains a high adsorption capacity.

On the Role of Hydroxyl Groups on Cu/Al2O3 in CO2 Hydrogenation

Xiwen Song,Chengsheng Yang,Xianghong Li,Zhongyan Wang,Chunlei Pei,Zhi-Jian Zhao,Jinlong Gong

Understanding the nature of adsorbates and intermediates on catalytic surfaces is critical for the development of highly efficient systems for CO2 conversion. However, the role of structural hydroxyl groups in CO2 hydrogenation is still under debate. This paper describes an experimental study on the nature of surface-bound hydroxyl groups over Al2O3-supported Cu catalysts for CO2 reduction. A model 5 wt % Cu/Al2O3 catalyst with stable hydroxyl groups was prepared. The structural hydroxyl groups were modulated by the hydration of unsaturated Al3+ sites, which were introduced by the evaporation-induced self-assembly method. Terminal hydroxyl groups (T-OH*) were found to significantly facilitate the conversion of CO2, while the AlVI-T-OH and AlIV-T-OH species promoted the formation of Al-b-HCOO and Al-m-HCOO species, respectively, accompanied with the increase in methanol and dimethyl ether yields. The reaction behavior of hydroxyl species was further investigated by in situ IR experiments with HD isotope exchange on Cu/Al2O3. T-OH* were identified as active sites participating in the formation of key intermediates, while more hydroxyl sites were occupied by formate species with the H coadsorbed on the Cu surfaces.

Cu/Al2O3 aerogels for high-efficiency and rapid iodide elimination from water

Xinyu Zhou,Pin Mao,Huiran Jin,Wanxia Huang,Aotian Gu,Kaiwei Chen,Shan Yun,Jing Chen,Yi Yang

Cu-based functional materials are excellent candidates for the elimination of iodine anions. However, the low utilization rate of Cu and its unsatisfactory adsorption performance limit its large-scale practical applications. This paper proposes a co-gelation method to obtain Cu/Al 2 O 3 aerogels with a high specific area (537 m 2 /g). Cu/Al 2 O 3 aerogels have a hierarchical porous structure and contain a high proportion of Cu (20.5 wt%). The high dispersibility of Cu, which is based on an in-situ gel process, provides conditions for the high-efficiency elimination of iodide anions. We conducted adsorption experiments that demonstrated that the fabricated Cu/Al 2 O 3 aerogel had an ultrahigh adsorption capacity (407.6 mg/g) and a fast adsorption equilibrium time (0.5 h) for iodide anions. Additionally, the Cu/Al 2 O 3 aerogel could selectively capture iodine anions even in the presence of high concentrations of competing ions (NO 3 - , SO 4 2- , and Cl - at 60 mmol/L). Importantly, the aerogel can operate in a wide pH range of 3–11 without causing secondary pollution. This work demonstrates that low-cost Cu/Al 2 O 3 aerogels exhibit great potential for eliminating radioactive iodine anions.

A CuZn-BTC derived stable Cu/ZnO@SiO2 catalyst for ethanol dehydrogenation

Haolan Liu,Zhili Chang,Jie Fu,Zhaoyin Hou

Cu-based catalysts play pivotal role in many industrial processes, however, its application under high temperature is restricted due to the low Tammann temperature of Cu. Improving the stability and activity of Cu-based catalysts at high temperature is a challenge. In this work, a stable Cu/ZnO@SiO 2 catalyst was prepared, in which silicon was introduced into CuZn-BTC precursor via a steam-assisted hydrolysis method before calcination and reduction. Characterizations found that Cu/ZnO@SiO 2 catalyst prepared via above strategy possesses increased surface area, more exposed active sites and excellent stability for ethanol dehydrogenation than Cu/ZnO (prepared from CuZn-BTC without SiO 2 ). It was confirmed that the space-time yield of acetaldehyde reached 9.0 g-acetaldehyde/g-cat/h, and Cu/ZnO@SiO 2 could maintain its activity within 200 h at 350 °C due to the ZnO decorated Cu particles (Cu/ZnO) were encapsulated in the octahedral shaped SiO 2 hollow.

Bioinspired Pd-Cu Alloy Nanoparticles as Accept Agent for Dye Degradation Performances

Shiyue Chen,Yujun Yang,Mingjun Zhang,Xiaohong Ma,Xiaoxiao He,Teng Wang,Xi Hu,Xiang Mao

Dye degradation is a key reaction in organic decomposition production through electron donor transferring. Palladium (Pd) is the best-known element for synthesis Pd-based catalyst, the surface status determines the scope of relative applications. Here we first prepare Pd-Cu alloy nanoparticles (NPs) by co-reduction of Cu(acac)2(acac = acetylacetonate) and Pd(C5HF6O2)2in the presence of sodium borohydride (NaBH4) and glutathione (GSH). The obtained Pd-Cu is about ~10 nm with super-hydrophilicity in aqueous mediums. The structural analysis clearly demonstrated the uniform distribution of Pd and Cu element. The colloidal solution keeps stability even during 30 days. Bimetallic Pd-Cu NPs shows biocompatibility in form of cell lines (IMEF, HACAT, and 239 T) exposed to colloidal solution (50 µg mL−1) for 2 days. It shows the catalytic multi-performance for dye degradation such as methyl orange (MO), rhodamine B (RhB), and methylene blue (MB), respectively. The as-synthesized nanoparticles showed one of the best multiple catalytic activities in the industrially important (electro)-catalytic reduction of 4-nitrophenol (4-NP) to corresponding amines with noticeable reduced reaction time and increased rate constant without the use of any large area support. In addition, it exhibits peroxidase-like activity in the 3, 3′, 5, 5′-Tetramethylbenzidine (TMB) color test and exhibit obvious difference with previous individual metal materials. By treated with high intensity focused ultrasound filed (HIFU), Pd-Cu NPs might be recrystallized and decreased the diameters than before. The enhancement in catalytic performance is observed obviously. This work expedites rational design and synthesis of the high-hierarchy alloy catalyst for biological and environment-friendly agents.Keywords:Pd-Cu NPs;hydrophilic;biocompatibility;catalytic agent;dye degradation

Synthesis and H2S-Sensing Properties of MOF-Derived Cu-Doped ZnO Nanocages

Beiying Qi,Xinchang Wang,Xinyue Wang,Jipeng Cheng,Yuanyuan Shang

Metal–organic framework (MOF)-derived pure ZnO and Cu-doped ZnO nanocages were fabricated by calcining a zeolitic imidazole framework (ZIF-8) and Cu-doped ZIF-8. The morphology and crystal structure of the samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). It was found that Cu doping did not change the crystal structures and morphologies of MOF-derived ZnO nanocages. The H2S-sensing properties of the sensors based on ZnO and Cu-doped ZnO nanocages were investigated. The results indicated that the H2S-sensing properties of MOF-derived ZnO nanocages were effectively improved by Cu doping, and the optimal doping content was 3 at%. Moreover, 3 at% Cu-doped ZnO nanocages showed the highest response of 4733 for 5 ppm H2S at 200 °C, and the detection limit could be as low as 20 ppb. The gas-sensing mechanism was also discussed.Keywords:MOF-derived ZnO;nanocages;Cu doping;H2S sensing