ACS Applied Nano Materials
·
2022
·
IF 6.14
Sainan Cao,Bingjie Zou,Jingxia Yang,Jinjie Wang,Huangdi Feng
A heterogeneous catalyst CuO–CeO2 with a hollow structure was successfully synthesized by assembling CuO on the outer surface of CeO2 hollow spheres through a layer-by-layer deposition strategy. Further reduction under a H2 atmosphere was carried out to modify its surface state, resulting in sample r-CuO–CeO2. The catalysts were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform-infrared spectroscopy (FT-IR). SEM and TEM showed that the synthesized catalysts had a hollow sphere structure, which can expose more active sites and promote mass transfer. The results of XPS revealed that the content of Cu0&Cu+ increased from 13.6 to 19.0% after H2 reduction, which was conducive to the activation of terminal alkyne to promote the annulation/A3-coupling reaction. The conversion of this cascade reaction with the r-CuO–CeO2 catalyst can reach more than 95%, while the value was only 55% by using CuO–CeO2 as a catalyst. Moreover, the r-CuO–CeO2 catalyst showed a good recycle property and group compatibility in the general applicability of the cascade annulation/A3-coupling reaction, providing a series of propargylamine derivatives in good chemoselectivity.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 32
·e202402012
·
IF 1.9
KangDi Chen,Siqi Chai,Guoqiang Li,Zeyu Li,Youqian Wang,Heting Li,Liwei Ma,Mai Wei,Guojie Zhang,Ying Wang
Graphical H 2 reduction reduces part of Cu 2+ to Cu + and Ce 4+ to Ce 3+ on the catalyst surface, and Cu and Ce can be stably anchored on the surface of the Cu−Ce/AC catalyst, which effectively improves the dispersion of the Cu component, and then slows down the loss of metal Cu. In this study, we utilized the carbon precursor derived from walnut shells to synthesize a series of Ce-modified Cu-based carbon catalysts (Cu−Ce/AC) via the impregnation method. We investigated the performance and stability of Cu−Ce/AC catalysts for CWAO phenol after H 2 reduction at various temperatures. The Cu−Ce/AC-250 catalyst exhibited its highest performance at 250 °C, achieving complete phenol conversion. Characterization results from techniques including XRD, BET, FTIR, ICP-OES, SEM-EDS, XPS, and H 2 -TPR indicated that the active components of the H 2 -reduced catalysts were more evenly distributed across the catalyst surface, thereby enhancing the availability of reactive sites for phenol oxidation. Simultaneously, under the appropriate temperature, the H 2 atmosphere can reduce a portion of the Cu 2+ on the catalyst surface to Cu + , thereby mitigating the loss of Cu components.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Xing Liu,Jing Wang,Yuting Zhang,Gang Guo,Jiakuan Yang,Shushan Yuan,Bart Van der Bruggen
Catalytic ceramic membranes (CCM) have attracted increasing attention in membrane material research due to their catalytic and separation functions. However, it is difficult to obtain stable CCM with excellent catalytic performance via common methods. Herein, SiC ceramic membrane loaded with Co, Cu bimetal were prepared by vacuum filtration method and heat treated at H 2 atmosphere (CoCu@SiC-H CCM). Results confirmed that heat-treated at H 2 atmosphere can enhance the catalytic performance of membrane. The first-order rate constant of the CoCu@SiC-H CCM/ peroxymonosulfate(PMS) system reached 0.01473 ms −1 , which is 10 3 -10 5 times greater than previously researches (0.0409–0.7588 min −1 ). Optimal CoCu@SiC-H CCM/PMS system achieved 98.02 % degradation of sulfamethoxazole in 1 min. The CoCu@SiC-H CCM presents outstanding catalytic performance due to the generation of Co 0 and the increase of oxygen vacancy concentration. OH and SO 4 − play important roles in the CoCu@SiC-H CCM/PMS degradation system. This work provides a new design method for preparing catalytic ceramic membranes with excellent catalytic performance, which can efficiently treat refractory wastewater in harsh environments.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 22
·8145-8152
·
IF 5.7
Dongkai Hu,Mavlanjan Rahman,Shuifu Liu,Lina Shen,Pengpeng Dai,Dawei Wen,Mingmei Wu
While numerous approaches have been devised to optimize the luminescence properties of Eu2+-activated phosphors, the quest for a simple design strategy to achieve color-tunable Eu2+ emission remains a significant challenge. Here, we present a straightforward, doping-free method to tailor the site occupation of Eu2+ and modify its luminescence properties. In the pristine sample, the NaBaB9O15 (NBB) host featuring two cation sites (Na+ and Ba2+), Eu2+ exclusively occupies the Ba2+ site, resulting in blue emission when the NBB:Eu2+ phosphor is synthesized in a H2 reducing atmosphere. When we use CO instead of a H2 reducing atmosphere, impressively, the formation energy required for heterovalent substitution of Na+ by Eu2+ is lowered, leading to the emergence of a distinct green emission band. Significantly, the resultant phosphor NBB:Eu2+@CO exhibits not only a high internal quantum yield of 85.1% and zero-thermal-quenching behavior within the temperature range of 25–200 °C but also wavelength-tunable emission. Benefitting from the multi-color luminescence of the NBB:Eu2+@CO phosphor, its optical applications will no longer be confined to general lighting but extend to anti-counterfeiting and encryption. This study provides a novel design methodology for optimizing the optical properties of Eu2+-activated phosphors.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）