ACTA PHYSICO-CHIMICA SINICA
·
2024
·
IF 10.8
Zhuoyan Lv,Yangming Ding,Leilei Kang,Lin Li,Xiao Yan Liu,Aiqin Wang,Tao Zhang
Direct epoxidation of propylene (DEP) by molecular oxygen is an ideal way to synthesize propylene oxide (PO), yet it remains quite challenging. We demonstrated here that the PO formation rate and selectivity could be enhanced simultaneously through photo-thermo-catalysis over the CuO x /TiO 2 catalyst. At 180 °C, by introducing light, the PO formation rate increased more than 20-fold (from 8.2 to 180.6 μmol g −1 h −1 ) and the corresponding selectivity improved more than 3-fold (from 8 % to 27 %), breaking the traditional perception that the semiconductors exhibit very low reactivity for this reaction. Kinetic study results showed that the apparent activation energy for PO formation could sharply decrease under light irradiation (from 95 to 40 kJ mol −1 ). In situ electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were applied to characterize the dynamics of the valence state of the copper oxide species and the activation intermediates of molecular oxygen. Evidence for the activation of oxygen, which could direct to the PO formation pathway, was captured. The light-driven electrons could promote the formation of active Cu + , which could form the side-on μ-peroxo Cu(II) 2 structure, weaken the O–O bond, and improve the PO formation rate and selectivity. This work paves a new way for designing semiconductor-supported photocatalysts for DEP reactions with molecular oxygen.
研究领域:
化学工程
·
催化科学
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DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Shunfeng Li,Tingting Song,Wenting Zhou,Zenglin Wang,Yi Ma
Cocatalyst act as the active site usually plays an important role in both photocatalytic hydrogen evolution reaction (HER) and carbon dioxide reduction reaction (CO 2 RR). As the size, distribution, location, contact behavior with semiconductor etc. show significant effects for the activity. In this work, the active site environment (aggregation state of the active site of the cocatalyst) was modulated by locating the different amounts of CuO x nanoparticles (NPs) into the porous TiO 2 (CuO x @TiO 2 ), which was achieved by calcination of Cu@MIL-125 as the precursor. The composition, morphology, and chemical state of the catalyst were analyzed by a series of characterization methods. The results showed that the embedded CuO x NPs exhibited obviously better dispersion than the externally supported ones, especially at the high loading amount. Cu NPs totally transformed to CuO at the lower loading amount, while it transformed to CuO x with partial Cu (I) species existence at the higher loading amount. Photocatalytic reactions showed that the activity of CuO x @TiO 2 was ∼ twice that of the traditional outside loading catalyst CuO x /TiO 2 in both HER and CO 2 RR. The high HER activity was obtained at relatively lower loading capacity (0.200 wt%∼0.500 wt%), while CO 2 RR was the advantageous reaction at higher loading capacity (5.000∼15.000 wt%). Apparently, CuO x @TiO 2 offered a quite different active site environment for the two type of reactions. The embedded structure can provide highly dispersed single active sites for HER at lower loading capacity, while it facilitates the formation of multi-electron environment under irradiation for CO 2 RR at higher loading capacity. The construction of an appropriate active center environment determines the occurrence of high-efficiency photocatalytic reactions.
研究领域:
材料科学
·
能源化学
·
环境科学
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产品关联
DOI
高影响因子
Nanomaterials
·
2024
·Vol. 14
·期 23
·1930
·
IF 4.4
Sha Ni,Wenjing Wu,Zichao Yang,Min Zhang,Jianjun Yang
The Cu cocatalyst supported on the surface of TiO2photocatalysts has demonstrated unique activity and selectivity in photocatalytic CO2reduction. The valence state of copper significantly influences the catalytic process; however, due to the inherent instability of copper’s valence states, the precise role of different valence states in CO2reduction remains inadequately understood. In this study, CuOx/TiO2catalysts were synthesized using an in situ growth reduction method, and we investigated the impact of various valence copper species on CO2photocatalytic reduction. Our results indicate that Cu+and Cu0serve as primary active sites, with the selectivity for CH4and CO products during CO2photoreduction being closely related to their respective ratios on the catalyst surface. The adsorption and activation mechanisms of CO on both Cu+and Cu0surfaces are identified as critical factors determining product selectivity in photocatalytic processes. Furthermore, it is confirmed that Cu+primarily facilitates CH4production while Cu0is responsible for generating CO. This study provides valuable insights into developing highly selective photocatalysts.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 40
·31708-31715
·
IF 3.84
Dongsheng Zhou,Zhiyuan Ren,Bo Li,Zhaoxia Ma,Xiaobin Zhang,Hangsheng Yang
Hexagonal boron nitride (hBN) was used as a CuOX/TiO2 catalyst carrier and its effect on NO reduction with NH3 was studied. After hBN was treated with concentrated HNO3, CuOX/TiO2 nanoparticles were dispersed well onto hBN, and the addition of hBN was found to promote NO oxidation, while at the same time suppress NH3 oxidation to NO, and thus promoted the selective catalytic reduction of NO at reaction temperatures between 150 to 350 °C, and a high de-NOX efficiency of 90.6% was achieved at 275 °C. Our study indicates that hBN is a promising catalyst promoter and carrier with excellent stability compared to carbonaceous materials.
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2026
·Vol. 18
·期 31
·42970-42981
·
IF 7.8
Ma Chaofan,Su Huiyu,Liu Zhongneng,Zhu Chaoqi,Yang Yazhou,Zeng Dawen
It is crucial to detect hydrogen (H 2 ) release from battery packs to provide early warning of battery thermal runaway. In this article, the hollow octahedral CuO x /TiO 2 were prepared using an efficient MOF template strategy, and nitrogen (N) -doped carbon (C) nanofibers embedded with CuO x /TiO 2 were designed by electrospinning, which were CuO x /TiO 2 @NCFs. The hollow heterojunctions (CuO x /TiO 2 ) formed based on MOF templates can reduce the recombination rate of carriers in TiO 2 , and DFT calculations reveal charge transfer occurring at the heterojunction, with a substantial migration of electrons from TiO 2 to CuO, significantly enhancing the ability of TiO 2 surface to adsorb H 2 . Simultaneously, the nanofibers composed of CuO x /TiO 2 and PAN contain substantial amounts of nitrogen and carbon. The introduced N atoms can activate the adjacent C atoms, the 3D framework constructed from N-doped C nanofibers exhibits extremely strong electron transport capability. At the optimal TiO 2 :PAN ratio of 4.0:1, the sensor achieves the response of 48% toward 10 ppm H 2 , and can detect as low as 20 ppb H 2 at room temperature, which is a potential competitive candidate for monitoring LIBs thermal runaway.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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