MATERIALS CHEMISTRY AND PHYSICS
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2022
·
IF 4.778
Xijun Li,Sifan Zhang,Lihua Zhu,Jun Liu,Huan Zhang,Ning Zhao,Bing Hui Chen
Herein, a series of the Pt-based bimetallic catalysts (PtM x /SBA-15) are gained by using ultrasonic incipient wetness impregnation method (M = Co, Cu, Ni or Zn). The experimental results show that the catalytic performance (including catalytic activity (turnover frequency-TOF), selectivity to crotyl alcohol) of PtCo x /SBA-15 for catalyzing crotonaldehyde selective hydrogenation is the best among PtM x /SBA-15. Additionally, the ratio of Pt/Co in the PtCo x /SBA-15 catalysts is changed to successfully synthesize PtCo/SBA-15, PtCo 2 /SBA-15, PtCo 5 /SBA-15. It demonstrates that the selectivity of the PtCo x /SBA-15 catalysts for crotonaldehyde selective hydrogenation to crotyl alcohol is significantly improved with the increase of the Co content. The PtCo 5 /SBA-15 catalyst provides 83.8% conversion of crotonaldehyde, 94.3% selectivity to crotyl alcohol and TOF of 910.5 h −1 under mild reaction conditions (3.0 MPa H 2 , 80 °C and 2.0 h). And PtCo 5 /SBA-15 has much better catalytic performance (higher catalytic activity and selectivity to crotyl alcohol) than PtCu 5 /SBA-15, PtNi 5 /SBA-15 and PtZn 5 /SBA-15. The reasons are as follows: (1) PtCo alloy forms, which is conducive to crotonaldehyde adsorption and activation; (2) there is an appropriate synergy effect between Pt and Co, greatly improving the capacity of the catalyst activating hydrogen under mild conditions; (3) the electron transfers from Co to Pt, resulting in the increase of Pt electron density and decrease of Co electron density, then the Co sites are advantageous to C O group adsorption and activation and Pt sites for H 2 adsorbing and activating; (4) with the increase of the Co proportion in PtCo x /SBA-15, the synergy effect between Pt and Co in PtCo alloy strengthens and thus increases the selectivity of C O group hydrogenation.
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ACS Sustainable Chemistry & Engineering
·
2023
·
IF 8.4
Hong Du,Xiuyun Ma,Miao Jiang,Siyuan Zhao,Qi Fang,Xiumei Liu,Zongchao Conrad Zhang
Xylitol is a value-added health product from the hemicellulose component in biomass. In this work, highly efficient Cu–Ni/SiO2 catalysts are developed for the production of xylitol by means of xylose hydrogenation. The bimetallic catalysts exhibit higher activity compared to the corresponding monometallic nickel or copper catalyst and the currently used industrial Raney nickel catalyst. The bimetallic catalyst with a higher ratio of nickel to copper shows a better performance. The 5Cu15Ni/SiO2 catalyst exhibits a xylose conversion of 96% accompanied by higher than 99% selectivity to xylitol under the moderate conditions of 100 °C and 3MPa H2. The bimetallic catalysts show improved performances when they are activated at a low temperature. The apparent activation energies of xylose hydrogenation over the 5Cu15Ni/SiO2 and 20Ni/SiO2 catalysts are 16.6 and 25.2 kJ/mol, respectively. The formation of the Cu–Ni alloy leads to a lower activation energy and thus superior performance for xylose hydrogenation to xylitol.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Jingjing Niu,Zhe Xue,Jiuchao Tang,Saravanan Rajendran,Xinyu Zhang,Jiaqian Qin
Developing efficient, economic, and environment-friendly electrocatalysts to meet the industrialized hydrogen evolution reaction (HER) needs is highly desired for dealing with the energy crisis. Under the known premise, how to reasonably control the doping amount of copper greatly influences the structure and is one of the key factors affecting the performance of the catalyst. Herein, a series of Ni–Cu–C electrocatalysts are successfully synthesized through a simple electrodeposition method. The unique dendritic morphology can be obtained by adjusting the different glucose concentrations . DFT simulation reveals that the proper proportion of copper can significantly modulate the H adsorption-free energy Δ G H ∗ It can boost the intrinsic activity of Ni–Cu–C catalysts. NCC-3 delivers an overpotential of 87 mV and 165 mV in alkaline media at the current density of 10 mA cm −2 and 100 mA cm −2 , respectively and presents outstanding long-term stability for 50 h. Such excellent HER activity stems from a large ECSA area and better electron-transfer ability. The study presents a feasible way to control metal alloy catalysts' composition in the electrodeposition process .
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FUEL
·
2023
·
IF 7.4
Juan Li,Xiaolei Jiang,Mingyuan Zhu,Bin Dai
Oxidative desulfurization (ODS) is a promising technique for obtaining clean fuel. Designing and researching zirconium-based metal–organic frameworks (Zr-MOFs) with bimetallic catalytic sites are encouraging for its further development. In this study, Cu(Ⅰ)-MOF-808 was successfully synthesized through anchoring Cu + in MOF-808. Pyridine infrared spectrum (Py-IR) and NH 3 temperature programmed desorption (NH 3 -TPD) confirmed that Lewis (L) acid sites existed in the synthesized material. Cu(Ⅰ)-MOF-808 was applied into the ODS reaction, during the reaction process, L acid sites adsorbed sulfide, Cu + sustainably provided electron to H 2 O 2 to formed into •OH, with the synergistic effect of L acid sites and Cu + , 99.9 % of the dibenzothiophene was oxidated to dibenzothiophene sulfone in 120 min. In addition, the cyclic experiment indicated that the ODS performance of Cu(Ⅰ)-MOF-808 was maintained at 99.2 % after 12 times recycling. Powder X-ray diffraction (PXRD) spectra indicated the framework structure of the reused catalyst was stable, inductively coupled plasma optical emission spectrometer (ICP-OES) result displayed no metal ions (Zr, Cu) leaching after the ODS reaction, which also proved the catalytic stability of the Cu(Ⅰ)-MOF-808.
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Small
·
2022
·Vol. 18
·期 23
·2201200
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IF 15.153
Peng Jing,Peixin Liu,Minghao Hu,Xuan Xu,Baocang Liu,Jun Zhang
Electrochemical nitrogen reduction powered by renewable electricity is a promising strategy to produce ammonia. However, the lack of efficient yet cheap electrocatalysts remains the biggest challenge. Herein, hybrid Cu 2 O-CeO 2 -C nanorods are prepared on copper mesh through a metal-organic framework template route. The Cu-loaded Ce-MOF is thermally converted to Cu 2 O-CeO 2 heterojunctions with interfacial Cu-[O X ]-Ce structures embedded in carbon. Theoretical calculations reveal the lower formation energy of oxygen vacancies in Cu-[O X ]-Ce structures than in the Cu 2 O or CeO 2 phase. The Cu-[O X ]-Ce structures with oxygen vacancies enable the formation of interfacial electron-rich Cu(I) species which show significantly enhanced performance toward electrocatalytic nitrogen reduction with an NH 3 yield of 6.37 × 10 −3 µg s −1 cm −2 and a Faradaic efficiency of 18.21% in 0.10 m KOH at −0.3 V versus reversible hydrogen electrode. This work highlights the importance of modulation of charge distribution of Cu-based electrocatalysts to boost the activity toward nitrogen reduction.
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Nanomaterials
·
2022
·Vol. 12
·期 5
·811
·
IF 5.719
Kang-Ping Cui,Yu-Ying He,Kai-Jie Xu,Yu Zhang,Chang-Bin Chen,Zheng-Jiang Xu,Xing Chen
In this work, the combination of high surface area diatomite with Fe and Cu bimetallic MOF material catalysts (Fe0.25Cu0.75(BDC)@DE) were synthesized by traditional solvothermal method, and exhibited efficient degradation performance to tetracycline hydrochloride (TC). The degradation results showed: Within 120 min, about 93% of TC was degraded under the optimal conditions. From the physical–chemical characterization, it can be seen that Fe and Cu play crucial roles in the reduction of Fe3+because of their synergistic effect. The synergistic effect can not only increase the generation of hydroxyl radicals (•OH), but also improve the degradation efficiency of TC. The Lewis acid property of Cu achieved the pH range of reaction system has been expanded, and it made the material degrade well under both neutral and acidic conditions. Loading into diatomite can reduce agglomeration and metal ion leaching, thus the novel catalysts exhibited low metal ion leaching. This catalyst has good structural stability, and less loss of performance after five reaction cycles, and the degradation efficiency of the material still reached 81.8%. High performance liquid chromatography–mass spectrometry was used to analyze the degradation intermediates of TC, it provided a deep insight of the mechanism and degradation pathway of TC by bimetallic MOFs. This allows us to gain a deeper understanding of the catalytic mechanism and degradation pathway of TC degradation by bimetallic MOFS catalysts. This work has not only achieved important progress in developing high-performance catalysts for TC degradation, but has also provided useful information for the development of MOF-based catalysts for rapid environmental remediation.Keywords:Fenton-like catalyst;bimetallic MOF;diatomite;synergistic effect;antibiotics
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CHINESE JOURNAL OF CATALYSIS
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2022
·
IF 12.92
Shi-Qun Cheng,Xue-Fei Weng,Qing-Nan Wang,Bai-Chuan Zhou,Wen-Cui Li,Ming-Run Li,Lei He,Dong-Qi Wang,An-Hui Lu
Copper-based heterogeneous catalysts commonly exhibit uncontrolled growth of copper species under reaction conditions because of the low Hüttig temperature (surface mobility of atoms) and Tamman temperature (bulk mobility) for copper at just 134 and 405 °C, respectively. Herein, we report the use of defect-enriched hexagonal boron nitride nanosheets (BNSs) as a support to anchor the Cu species, which resulted in superior dispersion of the Cu species. The obtained Cu/BNS catalyst was highly stable for ethanol dehydrogenation , with a high selectivity of 98% for producing acetaldehyde and an exceptionally high acetaldehyde productivity of 7.33 g AcH g cat –1 h –1 under a weight hourly space velocity of 9.6 g EtOH g cat –1 h –1 . The overall performance of our designed catalyst far exceeded that of most reported heterogeneous catalysts in terms of the stability of the Cu species and the yield of acetaldehyde in this reaction. The hydroxyl groups at the defect edges of BNS were responsible for the stabilization of the copper species, and the metal-support interaction was reinforced through charge transfer, as evidenced by coupling atomic resolution images with probe molecule infrared spectroscopy and X-ray photoelectron spectroscopy. A designed in situ diffuse reflectance infrared Fourier transform spectroscopy study of ethanol/acetaldehyde adsorption further revealed that Cu/BNS favored ethanol adsorption while suppressing acetaldehyde adsorption and further side reactions. This study demonstrates a new method for designing highly dispersed Cu-based catalysts with high durability.
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Materials Today Sustainability
·
2022
·
IF 7.244
X. Tai,B. Wu,J. Bao,W. Qu,L. Zhao,Z. Wang
Rational synthesis of bimetallic electrocatalysts with the special geometric structure for direct formic acid fuel cells remains yet challenging. Herein, a facile synthetic strategy is presented to prepare the bimetallic Pd–Cu alloy nanospheres (Pd–Cu ANSs) catalysts based on the galvanic replacement and high-temperature reconstruction. The formation mechanism of Pd–Cu ANSs is studied thoroughly from comprehensive characterizations and control experiments. The optimized Pd–Cu ANSs with unique nanosphere structure as well as regulated electronic structure provide excellent electrocatalytic performance for formic acid oxidation reaction (FAOR) with a specific activity of 6.11 mA cm - 2 Pd and mass activity of 1569.48 mA mg -1 Pd , which are 2.7 times and 3.5 times as high as these of the Pd/C catalyst. This synthetic method outlined here could provide a new pathway for noble metal-based alloy nanomaterials for diverse applications.
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Results in Chemistry
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2022
·
IF 0
Han Sun,Haiping Huang,Chao Hu,Yu Yan,Yongmei Hu,Shengda Guo,Jing-Lin Chen
Cu-Ni oxide nanocomposite was synthesized via solvothermal method with nickel (II) nitrate and copper nitrate as Ni and Cu resource respectively. AuNPs/oxide nanocomposite was obtained by dispersing the oxide into the pre-synthesized Au colloid. Transmission electron microscope (TEM) shows that the synthesized oxides are nanoplate morphology. Interplanar distance from the high resolution TEM (HRTEM) image shows that the Ni and Cu in the oxide are multivalent state. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterization further proves that the Ni and Cu are multivalent state, and the Au is Au 0 form in the nanocomposte. EDS-mapping images confirm large numbers of AuNPs are uniformly absorbed onto the ultra-thin multivalent Cu-Ni oxide nanoplate. The electrochemical properties of multivalent oxide (m-v oxide) with or without AuNPs decoration are investigated in 0.1 M potassium chloride electrolyte with 2.0 mM Ferri/Ferro-Cyanide. When employed for the electrochemical catalysis in methanol oxidation reaction (MOR), the AuNPs/m-v oxide exhibits better electrochemistry performance than m-v oxide. The current density of AuNPs/m-v oxide (21.1 mA/cm 2 ) is 3.4 times bigger than that of m-v oxide/GCE (6.2 mA/cm 2 ). What’s more, it shows good electrochemical stability and lower slope of the Tafel plot (41.87 mV/dec).
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ChemSusChem
·
2022
·Vol. 15
·期 7
·e202200226
·
IF 9.14
Huaxin Li,Xian Yue,Jing Che,Zhou Xiao,Xianbo Yu,Fenglei Sun,Chao Xue,Junhui Xiang
Graphical Networking at its best : The 3D self-supporting nanonetwork structure of Cu−Bi aerogels provides abundant reactive sites and electron transport channels for efficient electrocatalytic reduction of CO 2 to formate. The electrocatalytic reduction of CO 2 (CO 2 RR) to CO, formate, methane, and other high-value compounds is a promising technique. However, current electrocatalysts suffer from drawbacks such as few active catalytic sites, poor selectivity and low stability, etc, which restrict the practical application. Although monatomic metal catalysts have been widely reported in recent years, high performance non-noble metal aerogels were rarely investigated for electrocatalytic CO 2 RR. Herein, Cu−Bi aerogels with boosted CO 2 RR activity were well constructed by a simple one-step self-assembly method. The resultant Cu 1 Bi 2 exhibits excellent CO 2 RR activity with high faradaic efficiency (FE) of 96.57 % towards HCOOH at a potential of −0.9 V vs. RHE, and the FE HCOOH remains over 80.18 % in a wide potential window (−0.8 V to −1.2 V vs. RHE). It demonstrated that the enhanced CO 2 RR activity of Cu−Bi aerogels could be attributed to the 3D self-supporting structure of the catalysis, synergistic effect, and low interfacial charge transfer resistance.
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Journal of Materials Research and Technology-JMR&T
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2022
·
IF 6.267
Lihua Li,Shuang Liu,Meng Zhou,Yi Zhang,Shengli Liang,Jinliang Huang,Baohong Tian,Yongfeng Geng,Yijie Ban,Yong Liu,Yanlin Jia,Xu Li,Alex A. Volinsky
The effect of graphene on the thermal deformation of Cu/CeO 2 /Cr and GO-Cu/CeO 2 /Cr composites was studied. The isothermal compression test was carried out with Gleeble-1500D thermomechanical simulation device in the range of 600–900 °C and strain rate of 0.001–1 s −1 . The microstructure after deformation was characterized and analyzed by optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). The interaction of work hardening, dynamic recovery and dynamic recrystallization was described. The constitutive equation was successfully established. The results show that Cr particles are extruded into strips, and nano CeO 2 particles nail dislocations, which inhibit dynamic recovery and dynamic recrystallization. Dispersion strengthening, twin strengthening and grain refinement strengthening occur the thermal deformation of GO-Cu/CeO 2 /Cr composites, increase the flow stress and activation energy of the composites, and inhibit the dynamic recrystallization of the composites. When the hot deformation temperature increases, the texture orientation is strengthened. GO-Cu/CeO 2 /Cr composites have typical dynamic recovery characteristics and high temperature properties.
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ACS Catalysis
·
2022
·
IF 13.7
Min Huang,Shuyi Zhang,Bo Wu,Yao Wei,Xing Yu,Yongping Gan,Tiejun Lin,Fei Yu,Fanfei Sun,Zheng Jiang,Liangshu Zhong
Direct selective methane photooxidation to liquid oxygenates with high productivity and selectivity under mild reaction conditions is highly urgent but remains challenging. Herein, a Cu and W codoped TiO2 (Cu–W–TiO2) photocatalyst was fabricated to enable aerobic oxidation of methane into oxygenates with limited formation of CO2 under ambient temperature. A high oxygenate productivity of 34.5 mmol g–1 with a remarkable selectivity of 97.1% was achieved over the Cu–W–TiO2 photocatalyst. Based on structural characterizations and mechanism studies, it was suggested that the Cu species acted as hole traps, while oxygen vacancies and the W6+-dopant state worked as electron traps. The inhibited recombination of photogenerated carriers contributed to enhanced photocatalytic efficiency. The modulated electronic and band structure promoted the activation of methane and hindered the overoxidation of oxygenates.
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