SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Xiaohua Cao,Tianhao Ai,Zhizhi Xu,Jichang Lu,Dingkai Chen,Dedong He,Jiangping Liu,Rui Tian,Yutong Zhao,Yongming Luo
High sulfur resistance and high stability of catalysts are crucial for the catalytic decomposition of sulfur-containing volatile organic compounds. In this work, compared to 5Ce-MCM-41, the 5Cr-MCM-41 catalyst exhibited ultra-stability (no activity loss at 600 h) and higher sulfur resistance. The physical structure and chemical characteristics of the catalysts were analyzed by XRD , H 2 -TPR, NH 3 -TPD, CO 2 -TPD, XPS , and TEM. Combining the characterization results, we found that the 5Cr-MCM-41 catalyst presented outstanding catalytic performance due to superior reducibility and appropriate acidity, which results in the conversion of most of the C and S elements in the CH 3 SH to the gas-phase coke- and sulfur-containing products rather than accumulating on the catalyst surface. Meanwhile, the catalytic performance, reaction path, and deactivation mechanism of rare earth metal (Ce) and transition metal (Cr) modified MCM-41 catalysts were systematically investigated by in situ DRIFTS and DFT calculations. Additionally, a new active phase (sulfide state Cr 2 S 3 ) was proposed and proved via accurately designed experiments, which plays a significant role in the collaborative removal of CH 3 SH with hexavalent chromium (Cr(VI)). These findings are beneficial for designing high sulfur resistance catalysts for the removal of CH 3 SH and other sulfur-containing products.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2023
·Vol. 40
·期 12
·3059-3067
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IF 2.7
Yin Zihang,He Ruibo,Nie Fei,Wei Zhen,Jia Bo,Feng Qing,Fu Xiaolong,Zhang Wenyan
The oxygen evolution kinetics of industrial copper electrodeposition is slow, resulting in low electrocatalytic activity and high energy consumption. In this work, a quaternary composite of carbon coated active particles containing Mn, Co and Ce were prepared (Mn-Co 3 O 4 /CeO 2 @C), and Ti/Sb-SnO 2 /PbO 2 electrode doped with these active particles was prepared by co-electrodeposition. The microstructure and chemical composition of the electrode was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). Linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and Tafel polarization curve (Tafel) were used to study the electrochemical properties of anode materials. The results showed that the doping of Mn-Co 3 O 4 /CeO 2 @C active particles promoted the crystal transition of PbO 2 , decreased the average grain size, and the doping of Ce increases the average valence state of Co. The modified titanium electrode showed excellent catalytic activity of the oxygen evolution reaction (OER) characteristics. The overpotential of the doped Ti/Sb-SnO 2 /PbO 2 anode was only 453 mV when the current density was 20 mA cm −2 in 0.5 M H 2 SO 4 solution, which is 508 mV lower than that of the undoped Ti/Sb-SnO 2 /PbO 2 anode. In simulated copper electro-deposition experiments, the cell voltage was reduced by about 400 mV, compared to the undoped Ti/Sb-SnO 2 /PbO 2 electrode.
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ACS Nano
·
2023
·
IF 17.1
Yanfei Sun,Jiangzhou Xie,Zhenzhen Fu,Huiying Zhang,Yebo Yao,Yixiang Zhou,Xiaoxuan Wang,Shiyu Wang,Xueying Gao,Zheng Tang,Shuyuan Li,Xiaojun Wang,Kaiqi Nie,Zhiyu Yang,Yi-Ming Yan
Efficient conversion of carbon dioxide (CO2) into value-added materials and feedstocks, powered by renewable electricity, presents a promising strategy to reduce greenhouse gas emissions and close the anthropogenic carbon loop. Recently, there has been intense interest in Cu2O-based catalysts for the CO2 reduction reaction (CO2RR), owing to their capabilities in enhancing C–C coupling. However, the electrochemical instability of Cu+ in Cu2O leads to its inevitable reduction to Cu0, resulting in poor selectivity for C2+ products. Herein, we propose an unconventional and feasible strategy for stabilizing Cu+ through the construction of a Ce4+ 4f–O 2p–Cu+ 3d network structure in Ce-Cu2O. Experimental results and theoretical calculations confirm that the unconventional orbital hybridization near Ef based on the high-order Ce4+ 4f and 2p can more effectively inhibit the leaching of lattice oxygen, thereby stabilizing Cu+ in Ce-Cu2O, compared with traditional d–p hybridization. Compared to pure Cu2O, the Ce-Cu2O catalyst increased the ratio of C2H4/CO by 1.69-fold during the CO2RR at −1.3 V. Furthermore, in situ and ex situ spectroscopic techniques were utilized to track the oxidation valency of copper under CO2RR conditions with time resolution, identifying the well-maintained Cu+ species in the Ce-Cu2O catalyst. This work not only presents an avenue to CO2RR catalyst design involving the high-order 4f and 2p orbital hybridization but also provides deep insights into the metal-oxidation-state-dependent selectivity of catalysts.
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PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 30
·期 5
·11994-12004
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IF 5.19
Ye Chen,Fang Tingwei,Long Xinyi,Wang Hui,Chen Shao,Zhou Jie
Compared with that of the transition metal mixed oxide pellet catalyst, the catalytic activity of the supported mixed oxide catalyst was significantly reduced, which was limited in practical industrial applications. In this work, supported Cu-Mn-Ce mixed oxide catalysts were prepared by non-thermal plasma. Catalyst characterization result demonstrated that plasma treatment could promote the proportion of oxygen vacancy and enhance the adsorptive strength of VOCs on the surface of catalyst. Meanwhile, plasma treatment process exerted a slight influence on the pore structure and morphological property of the catalyst. Consequently, CMC/SiO 2 –P exhibited much higher catalytic activity than CMC/SiO 2 prepared by the incipient wetness impregnation method for the catalytic oxidation of toluene and n-hexane. Among the catalysts prepared, the 15%CMC/SiO 2 –P catalyst even exhibited a high catalytic activity comparable to that of the supported noble metal catalyst for the oxidation of the inert hexane. The T 98 of toluene and n-hexane over 15%CMC/SiO 2 –P was 260 and 280°C under the conditions of VOC concentration at 1000 ppm and WHSV at 20,000 mL·g −1 ·h −1 , respectively. This work provided a novel method for the preparation of the supported transition metal mixed oxide catalyst.
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高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Guangchun Song,Junjie Zhang,Huixian Huang,Xin Wang,Xiaoyun He,Yunbo Luo,Jin-cheng Li,Kunlun Huang,Nan Cheng
Rapid detection of pesticide residues based on enzyme mimics has recently attracted much interest. However, most nanozymes have low activity. Herein, a “single-atom Ce-N-C nanozyme” (SACe-N-C nanozyme) was rationally devised and verified to mimic peroxidase (POD-like) with superior activity. Based on its high POD-like activities and cascaded catalytic reactions with acetylcholinesterase (AChE), we constructed a bioactive paper for the detection of pesticide residues, which offered a portable approach to monitor fruits and vegetables within 30 min. More importantly, a 3D printed platform was integrated on the basis of SACe-N-C bioactive paper to achieve on-site portable testing of omethoate, methamidophos, carbofuran, and carbosulfan, showing limits of detection (LODs) of 55.83, 71.51, 81.81, and 74.98 ng/mL, respectively. The recovery rates were 84.09–104.68%. This study provided new insight into the design of novel single-atom nanozymes for cascaded catalytic detection and other rapid detection applications with high efficiency and low cost.
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高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2022
·
IF 7.926
Shuangli He,Jinghang Ren,Peng Cao
Low-temperature selective catalytic reduction (SCR) is effective and promising for converting NO x in flue gas into N 2 , with wide application prospects. However, low-temperature denitration (DeNO x ) catalysts are susceptible to SO 2 and H 2 O poisoning. Here, we prepared a monolithic Mn-Fe-Ce/Al 2 O 3 catalyst that exhibited excellent DeNO x performances at low temperatures. At 110 °C, the NO conversion rate of the catalyst was> 90%, exhibiting excellent resistances to H 2 O and SO 2 ·H 2 O and SO 2 are introduced at the same time, the efficiency is as high as 73%. Furthermore, The catalyst has a porous structure with abundant chemisorbed oxygen spices and exposed active, the reaction pathway on the catalyst proved to be the L-H mechanism based on in situ DRIFTS. This study also explored the mechanisms of low-temperature SCR catalyst poisoning by SO 2 and H 2 O, providing insights into the effects of SO 2 and H 2 O and theoretical support for the development of poisoning-resistant low-temperature SCR catalysts.
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DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 8
·3159-3169
·
IF 4.569
Qinghong Meng,Guoying Zhao,Qi Zhu,Xudong Sun,Ji-Guang Li
Doping Gd2LuAl5O12:Ce with a Ca2+/Si4+ pair produced a series of Gd1.97−xLuCaxAl5−xSixO12:0.03Ce (x = 0.0–1.2) garnet new phosphors, and remarkable regulation of the crystal structure and Ce3+ luminescence was achieved. Rietveld refinement and spectral analysis revealed that greater incorporation of Ca2+/Si4+ led to a higher lattice rigidity by cell contraction, a narrower bandgap, a longer average bond length/less distortion of the [CeO8] dodecahedron and decreased centroid shift/crystal field splitting of the Ce3+ 5d energy level. A blue-shifted 4f–5d1 transition, a narrower emission band, improved thermal stability of luminescence and a shorter fluorescence lifetime were observed with increasing Ca2+/Si4+ content. Applying the yellowish-green-emitting Gd0.77LuCa1.2Al3.8Si1.2O12:0.03Ce optimal phosphor (x = 1.2), together with a commercial CaAlSiN3:Eu red phosphor, in 450 nm-excited LED lighting produced a low CCT of ∼3625 K and a high CRI/R9 of ∼95.2/94.8, indicating that the phosphor has application potential in high-performance w-WLED.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Yu Zhang,Jiming Wang,Guojie Zhang,Jun Liu,Lizhen Dou,Ying Xu,Guoqiang Li
An appropriate preparation method is the essential to improve the catalyst performance. In this study, Co–Ce/AC-N catalysts were fabricated on N-doped activated carbon supports by impregnation, sol-gel, precipitation and mix methods, respectively. It was used to catalyze the combined steam and dry reforming of methane (CSDRM). The effects of different preparation methods on the catalyst performance were investigated by means of N 2 adsorption-desorption, XRD , H 2 -TPR, TEM, CO 2 -TPD, FTIR and XPS. Compare with the catalysts prepared by other methods, the catalyst prepared by impregnation exhibits a large surface area, high active metal dispersion, and strong metal-support interaction. Meanwhile, it also has strong basic sites and abundant oxygen vacancies . These greatly improve the activity and stability of the catalyst. The conversions of CH 4 and CO 2 at 650 °C were achieved 71.6% and 64.4%, and H 2 /CO was retained at 1.5.
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ACS Omega
·
2021
·
IF 3.512
Xiutao Li,Feng Zhang,Mengjie Zhang,Xiaomeng Zhou,Haijun Zhang
In this work, a series of rare earth-based metal–organic frameworks (RE-MOFs) with the same organic ligand were synthesized and studied as flame retardants on epoxy. Through thermogravimetric analysis, limiting oxide index, UL-94, and cone calorimeter tests, a Y-based MOF (Y-MOF) showed the best flame retardancy compared with a La-based MOF (La-MOF) and Ce-based MOF (Ce-MOF). Further research with Raman, X-ray photoelectron spectroscopy, and theoretical calculation revealed that the reasons for the different flame retardance performances of RE-MOFs resulted from the catalytic carbonizing abilities and the radical-trapping abilities of La, Ce, and Y.
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高影响因子
DALTON TRANSACTIONS
·
2021
·Vol. 51
·期 2
·645-654
·
IF 4.39
Qinghong Meng,Guoying Zhao,Qi Zhu,Xiaodong Li,Xudong Sun,Ji-Guang Li
Synergistic doping of the metastable Gd3Al5O12:Ce garnet with a Ca2+/Hf4+ pair and Sc3+ to form Gd2.97−xCaxHfxScyAl3O12:0.03Ce (x = 0.5–2.0, y = 0.0–1.5, x + y = 2.0) solid solution was conducted for the structural stabilization and photoluminescence manipulation. The site selection of Ca2+/Hf4+/Sc3+ dopants and the effects of doping on the crystal structure, local coordination, band structure and Ce3+ luminescence were revealed in detail with the results of XRD, Rietveld refinement, TEM, and UV-Vis/photoluminescence spectroscopy. A decrease in Ca2+/Hf4+ and an increase in the Sc3+ content were observed to shrink the lattice, widen the bandgap of the garnet host, red-shift the excitation/emission wavelength, broaden the emission band and shorten the fluorescence lifetime of Ce3+. The spectral changes were rationalized by considering the local coordination and crystal field splitting of the Ce3+ 5d energy level. Application of typical Gd0.97Ca2Hf2Al3O12:0.03Ce (x = 2.0, y = 0) cyan and Gd2.47Ca0.5Hf0.5Sc1.5Al3O12:0.03Ce (x = 0.5, y = 1.5) greenish-yellow phosphors in w-WLED lighting produced low correlated color temperatures of ∼3842 and 3514 K, high color rendering indices of ∼88 and 93 and favorable luminous efficacies of ∼32.9 and 14.7 lm/W under the excitation of 395 nm n-UV and 450 nm blue LED chips, respectively.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Chenxi Wang,Gang Lv,Yunqiang Li,Ye Liu,Chonglin Song
The selective catalytic reduction of nitrogen oxides by methane (CH 4 /NO X -SCR) is a potential technique for the abatement of the NO X emissions from lean-burn GDI engines, due to the excellent thermal stability of CH 4 . This work focuses on the promotion of In/SSZ-13 catalysts by Ce modification for the CH 4 /NO X -SCR performance at high temperatures. A series of In/SSZ-13 and Ce-In/SSZ-13 catalysts were prepared using the wetness impregnation method. The effects of Ce modification on the catalytic performance were analysed in detail using the scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectrum and temperature-programmed desorption/reduction techniques. The results show that the Ce modification significantly enhances the high-temperature activity of the In/SSZ-13 catalysts for the NO X -SCR reaction, especially for the 5 wt% Ce-15 wt% In/SSZ-13 sample which has more than 75% NO X conversion at 390–700 °C. In addition, the Ce modification enhances the water vapor tolerance of the catalyst sample. The Ce modification increases not only the concentration of surface chemisorption oxygen species, but also the relative amount of InO + species which serve as the main active sites for CH 4 activation. Furthermore, the incorporation of Ce into In/SSZ-13 greatly promotes NO X adsorption on the catalyst surface. Most importantly, the Ce modification makes In species well-dispersed on the catalyst surface and thus suppresses the formation of bulk In 2 O 3 species which are more active for the CH 4 non-selective oxidation. The combination of all these effects results in the Ce-In/SSZ-13 samples with the superior catalytic activity .
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JOURNAL OF LUMINESCENCE
·
2020
·
IF 3.28
Xing Cao,Shichang Sun,Bing Lu,Yan Liu,Rui Ma,Huiqun Cao,Hongzhi Ma,Hexun Huang
In order to overcome the shortcomings of insufficient red light component and poor thermal stability of commercial white light emitting diode (WLED), YAG:Ce, R (R: Gd 3+ , Pr 3+ , Gd 3+ and Pr 3+ ) fluorescent thin films were prepared by pulse laser deposition (PLD). The composition and microstructure, photoluminescence properties, and red-enhanced mechanism of co-doped YAG fluorescent thin films, as well as the electroluminescence behavior of the corresponding WLEDs were investigated. Results showed that the doping of Pr 3+ caused the emission spectrum energy of Ce 3+ to migrate, and an emission peak appeared at 606 nm in the red region. The doping of Gd 3+ caused the emission spectrum of Ce 3+ to shift to the red region, and the main peak position of the Ce 3+ emission spectrum is red-shifted from 523 nm to 548 nm. The YAG:Ce,Pr,Gd fluorescent film not only realized the improvement of red light components and red-shift, but also increased the energy transmission efficiency from 33.3% to 51.9%. Moreover, results of the color coordinate analysis also showed that the co-doping of Gd 3+ and Pr 3+ made the luminescence closer to the red region, reducing the color temperatures and hues changed to warm. Thus, tri-doped transparent fluorescent thin film were prospective for WLED application.
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