Journal of Materials Chemistry A
·
2023
·Vol. 11
·期 20
·10927-10937
·
IF 11.9
Jianyu Han,Zhixin Zhang,Zhuoran Xu,Lunhua He,Feiran Shen,Yehong Wang,Xuebin Liu,Meiling Guo,Zaihong Guan,Feng Wang
The interfaces in heterogeneous catalysts play an important role in their performances by either directly providing active sites through the synergistic effects from different catalyst compositions or indirectly modulating the state of active sites. However, constructing abundant interfaces in heterogeneous catalysts is a key scientific challenge since it requires the high dispersion of all catalyst compositions involved in substrate activation. A surface reduction strategy is proposed as the solution for this challenge, which creates a pyramid-type catalyst, (Pt/4nmCeO2)/SiO2, with maximized interfacial Pt–CeO2 sites as an example. Pt is chemically bound in surface reductive centers of 4 nm CeO2 nano-islands, generating stable Pt2+ sites with moderate hydrogenation capacity compared to Pt0 sites on bulk CeO2 and SiO2. This work facilitates the development of heterogeneous catalysts by presenting a high level of controlling the local chemical environment within nanomaterials.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 7
·期 2
·247-255
·
IF 5.976
Chunyan Jiang,Mikhail G. Brik,Alok M. Srivastava,Lihua Li,Mingying Peng
Mn4+ doped fluoride phosphors have attracted tremendous attention in the solid-state lighting field due to the outstanding feature of efficient narrow band red emission. However, poor resistance against moisture-induced luminescence quenching is a recognized obstacle for realizing their wider commercial use. Herein, we design and fabricate a highly stable red phosphor based on previously unnoticed Rb2SnF6:Mn4+, which, estimated by the single crystal X-ray diffraction data, crystallizes in the trigonal space group Pm1 with the lattice parameters a = b = 6.0323(12) Å, c = 4.7880(8) Å, and V = 150.89(7) Å3. The Rb2SnF6:Mn4+ as expected exhibits highly efficient red emission upon excitation by UV and blue light. Significantly, the poor water resistance is conquered by constructing a protective deactivated layer with surface reduction of Mn4+. A treatment solution with appropriate reducing ability is emphasized to obtain Rb2SnF6:Mn4+ with simultaneous high brightness and water resistance. The results show that the low concentration of H2C2O4 solution treated Rb2SnF6:Mn4+ preserves a bright red-emitting color analogous to its initial color and >95% of its initial emission intensity when immersing in water at room temperature (RT) and in boiling water for 3 h. Lastly, by employing H2C2O4 treated Rb2SnF6:Mn4+ as a red phosphor, a high quality WLED with a CRI of 90, CCT of 3936 K and luminous efficacy of 106.24 lm W−1 is fabricated. This work not only experimentally fabricates a new efficient and stable Rb2SnF6:Mn4+ phosphor that can be used for high performance warm WLEDs but also provides a deep insight into how to well address moisture-induced Mn4+ luminescence quenching through appropriate reduction of Mn4+, opening up new opportunities for future solid-state lighting purposes.
研究领域:
材料科学
·
固态照明
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2023
·
IF 2.8
Wang Yanghui,Jin Luyao,Xu Xintao,Li Jiaying,Fan Kaihao,Hu Bo,Shen Yi,Liu Xuesong
In this paper, MnO x /TiO 2 catalysts with different manganese contents were prepared by using vacuum over-impregnation method to support manganese on TiO 2 support. However, the activity temperature window was narrow and the denitrification efficiency was only 265–365 °C in the temperature zone above 80%. Therefore, doping W was used to improve the high temperature activity and broaden the activity temperature window. The experimental results show that the active temperature window of the catalyst is expanded to 260–550 °C when doping 20%WO 3 . The effects of tungsten doping on the structure and surface properties of the catalysts were investigated by XRD, TEM, Raman, XPS, H 2 -TPR and NH 3 -TPD. It is found that the increase of manganese content would increase the ratio of Mn 4+ and O α , and then improve the NH 3 -SCR activity at low temperature. Tungsten doping can provide more strong acid sites and improve the high temperature activity of the catalyst by inhibiting the oxidation of ammonia. Graphical Abstract
研究领域:
催化化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2019
·
IF 12.221
Yan-Rong Liu,Xue Li,Wen-Min Liao,Ai-Ping Jia,Yue-Juan Wang,Meng-Fei Luo,Ji-Qing Lu
The Pt catalysts supported on hexagonal BN (Pt/BN) are highly active and stable for propane combustion, with the highest specific reaction rate of 92.3 μmol gPt–1 s–1 and turnover frequency of 0.037 s–1 obtained on a 0.2Pt/BN catalyst at 220 °C. The Pt oxide in the catalyst could be partially reduced to the metallic state by propane during the reaction, which is beneficial for the improvement of activity, indicating that metallic Pt might be the active sites. The highly dispersed Pt particles stabilized at the grain boundary of BN could be more easily reduced in the reaction than those on the surface and thus are more active. Moreover, kinetic investigation reveals that the apparent activation energy of the Pt species at the grain boundary (111.6 ± 8.0 kJ mol–1) is much lower than that on the surface (172.4 ± 16.5 kJ mol–1), suggesting different reaction pathways on these catalysts and the possible participation of the grain boundary of the BN support in the reaction.
研究领域:
催化化学
·
环境化学
·
材料科学
·
表面科学
·
能源化学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Tao Wang,Benlong Yu,Long Mu,Zhilin Chen,Chao Xiao,Shuming Peng
The palladium oxide phase (PdOx) plays a critical role in catalytic methane oxidation and CO oxidation reactions. Precise characterization of supported PdOx by CO-FTIR spectroscopy is often accompanied by the reduction of PdOx by CO. Lowering the CO partial pressure to 0.05% CO/N2 (0.5 mbar) and the adsorption temperature to −130 °C is a proper condition to inhibit the reduction completely. Then CO-FTIR spectroscopy was conducted on a series of supported PdOx catalysts. We find that CO adsorbed on coordinatively unsaturated Pd atoms (Pdcus) on the PdOx surface gives three adsorption bands at ∼2145 cm–1. Three types of surface Pdcus atoms with different degrees of coordination unsaturation (types I, II, and III) exist in supported PdOx catalysts; their νCO are located at 2133, 2145, and 2160 cm–1, respectively. The order of coordination unsaturation of surface Pdcus should be type III < type II < type I. Since νCO of surface Pdcus is between νCO of Pd2+(CO) and Pd+(CO), the effective charge of surface Pdcus is 1 < n < 2. For small PdOx clusters in zeolite-supported PdOx catalysts, surface Pdcus atoms with more coordination unsaturation (i.e., step, edge, and corner sites) are more abundant, leading to greater IR intensity of adsorbed CO.
研究领域:
催化化学
·
表面化学
·
光谱学
·
材料科学
·
环境化学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Huiqi Zhang,Quansheng Cheng,Josh Haipeng Lei,Tianwei Hao,Chu-Xia Deng,Zikang Tang,Songnan Qu
Biocompatible metal-free carbon dots (CDs) with good photo-induced strong oxidation capacity in aqueous solutions are scarce for high-performance photocatalytic antibacterial and tumor therapy. In this work, we achieved effective visible light-induced cell death and antibacterial performance based on biocompatible metal-free CDs. The visible-light-induced reducing ability of the surface electron-withdrawing structure of the CDs allowed for the remaining photo-induced holes with high oxidation capacity to oxidize water molecules and generate hydroxyl radicals. Antibiotic-resistant bacteria were effectively inhibited by the CDs under xenon lamp irradiation with 450 nm long pass filter. Moreover, CD-based tumor photocatalytic therapy in mice was achieved using a xenon lamp with 450 nm long pass filter (0.3 W cm −2 ).
研究领域:
纳米技术
·
光催化
·
生物医学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Tong Chen,Rong Wang,Chen Sun,Debao Kong,Shengyong Lu,Xiaodong Li
In this study, a series of metal-organic frameworks (MOFs) derived binary porous MnCeO x catalysts were synthesized via solvothermal method for chlorobenzene (CB) oxidation . Compared with the catalysts from co-precipitation and sol-gel method, Mn1Ce1-MOF catalyst presented the best performance with T 90% at 242 °C and highest CO x yield of 94.6% at 400 °C, owing to its micropore-enriched structure, higher lattice oxygen ratio and better surface reducibility. The HCl selectivity of Mn1Ce1-MOF reached 91.3% at 400 °C. The gaseous byproducts over Mn1Ce1-MOF catalyst were identified and the degradation pathway of CB was proposed. The catalytic activity of Mn1Ce1-MOF catalyst at 300 °C could stabilize over 75% for 40 h. The oxidation of Mn 3+ and chlorine species adsorption were considered to be the main reasons for the catalyst inactivation. This work provides a highly-efficient MOFs templated porous metal oxide for tail gas purification.
研究领域:
催化
·
环境化学
·
材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2020
·
IF 2.627
Xiang Li,Bo Yang,Yaqin Wu,Saisai Lin,Lin Zhang
Homogeneous NaBH 4 -reduced Co 3 O 4 thin film electrodes with enhanced oxygen evolution electrocatalysis were obtained via a controlled-synthesis route. Firstly CoO x colloids were synthesized via ethylene glycol solvothermal method and cast on conductive glass substrates. The oxygen evolution reaction (OER) electrocatalysis of these as-prepared Co 3 O 4 thin films were then significantly enhanced via a simple surface reduction by NaBH 4 solution. The OER catalytic performance of the NaBH 4 -reduced thin films was strongly dependent on the NaBH 4 concentration. The use of NaBH 4 -reduced thin film electrodes for OER in alkaline solution supported higher current density and consequently negative shifts of the onset potential compared to that of the pristine. The optimal B 12.5, 20 -Co 3 O 4 thin films exhibited excellent OER catalytic performances: At the current density of 10 mA·cm −2 , a low overpotential of 365 mV and a small Tafel slope of 59.0 mV·dec −1 were observed. In addition, these B 12.5, 20 -Co 3 O 4 thin film electrodes possessed good stability that can well recover its OER performance in a 24-h chronoamperometric stability test.
研究领域:
电化学
·
材料科学
·
催化
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）