FUEL PROCESSING TECHNOLOGY
·
2023
·
IF 7.5
Yu Tang,Yi Cui,Gaosheng Ren,Ke Ma,Xiaoxun Ma,Chengyi Dai,Chunshan Song
In this study, the copper-mordenite zeolite (Cu-MOR) and non-thermal plasma were used to produce methanol and hydrogen from methane and water at low temperature (120 °C) without CO 2 formation. Energy efficiency for methanol and hydrogen were 68.8 mmol·kJ −1 and 562.3 mmol·kJ −1 , respectively, and the selectivity of methanol in liquid products reached 86%. The reaction mechanism likely involves methane being excited to methyl (·CH 3 ) and hydrogen radicals (·H) under DBD plasma conditions, which can then adsorb on the catalyst surface at the Cu 2 -(μ-O) 2+ active sites, accompanied by water co-adsorption to facilitate formation and desorption of methanol. XPS analysis showed that with the prolongation of reaction time, Cu 2 -(μ-O) 2+ was reduced to Cu + and Cu(II) hydroxide, and the catalyst had carbon deposition , resulting in the decrease of catalytic activity . It is also worth noting that in an oxygen atmosphere, Cu 2 -(μ-O) 2+ regenerates rapidly and eliminates catalyst carbon deposits . Trace oxygen was introduced into the reactor, and the reaction was carried out for 30 h, and the catalytic activity did not decrease.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Linkai Wang,Yu Han,Jian Wei,Qingjie Ge,Shijian Lu,Yanpeng Mao,Jian Sun
Hydrogenation of CO 2 into light olefins is an important route to carbon neutrality . Most of traditional researches focus on the catalyst component, structure, and promoter to enhance the selectivity of light olefins while ignoring the diffusion of products. Here, we report a NaFeZr-MOR composite catalyst for light olefin synthesis in CO 2 hydrogenation via pore confinement. The selectivity in hydrocarbons and STY (Space-time yields) of C 2–4 = is gradually increasing maximum up to 51.3% and 12.2 (mmol·g cat −1 . h −1 ), which lie in a high level among reported Fe-based catalysts. Further characterization revealed that the essence of selectivity change period is the accumulation and evolution of carbonaceous species, which causes the change of product diffusion behavior. It suppresses the escape of heavy hydrocarbons from MOR pores, leading to an increased light olefin, especially ethylene, which is called “dynamic confinement”. These findings provide a new insight for controlling low-carbon product selectivity in CO 2 hydrogenation.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2018
·
IF 0
Peipei Tao,Xinhuan Lu,Haifu Zhang,Run Jing,Fengfeng Huang,Sha Wu,Dan Zhou,Qinghua Xia
CoO x species is firstly introduced onto MOR (Mordenite) by impregnation with microwave heating to catalyze the epoxidation of α-pinene with air. The obtained samples have been characterized by X-ray diffraction, FTIR, SEM, TEM, BET surface area, porosity by N 2 adsorption. 7%CoO x /MOR catalyst exhibits remarkably higher activity and selectivity in the epoxidation of α-pinene than that prepared by traditional heating impregnation. The epoxidation conversion of α-pinene over 7%CoO x /MOR prepared by microwave heating reaches 92.7 mol% in 4 h at 90 °C, which is nearly 1.5 times that of the catalyst by traditional impregnation. This is due to the fact that CoO x nanoparticles are produced by microwave heating and uniformly dispersed on MOR.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
CATALYSIS TODAY
·
2022
·
IF 6.562
Yumeng Xia,Zehua Li,Ying Li,Kai Cai,Yunduo Liu,Jing Lv,Shouying Huang,Xinbin Ma
Dimethyl ether (DME) carbonylation is an important reaction for methyl acetate (MA) and ethanol production from syngas. Mordenite (MOR) has been used as an industrial catalyst due to the competitive catalytic properties, especially with extremely high selectivity of MA (>99%). Given the Brønsted acid sites (BAS) in 8-MR are proved the active centers, the properties of BAS are crucial factors that influence the reaction. Until now, most of the researches focus on increasing the number of BAS rather than tuning the acid strength. Here we modified H-MOR by Ga introduction using incipient wetness impregnation. Catalyst evaluation results suggest that Ga species can enhance DME conversion with a maintained MA selectivity. Combining with characterizations and DFT calculation, the textural and acidic properties along with the existing form of Ga species are determined. Further in-situ IR, theoretical and kinetics investigations demonstrated that the enhanced acid strength accelerates the reaction on Ga-modified MOR catalysts. This work inspires us that improving the acid strength is an efficient strategy for Brønsted acid-catalyzed reaction, such as DME carbonylation .
研究领域:
催化化学
·
理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 11
·e5925
·
IF 3.14
Jie Yao,Yan Wang,Suleiman Sabo Bello,Guangwen Xu,Lei Shi
As it is well known, Brønsted acid sites in 8-MR of H-MOR (mordenite) are selective for dimethyl ether (DME) carbonylation to methyl acetate, whereas those in 12-MR are more prone to methanol to olefin reaction. Interestingly, we observed that the Brønsted acid sites in 12-MR of H-MOR are highly active for dimethoxymethane (DMM) carbonylation to methyl methoxyacetate (MMAc), whereas those in 8-MR led to the formation of DME. A series of modified H-MOR catalysts with accurate regulation of Brønsted acid sites in 12-MR or 8-MR were successfully synthesized by selective Na + exchange or pyridine (Py) adsorption. Fourier-transform infrared (FT-IR) spectra, NH 3 -temperature-programmed desorption, Py-FT-IR, and inductively coupled plasma analyses suggested that Na + first occupied Brønsted acid sites in 8-MR and then replaced those in 12-MR. All Na + -exchanged catalysts exhibited significant acceleration on MMAc selectivity, and the ratio of Brønsted acid amount in 12-MR/total had a positive correlation with MMAc selectivity. The MMAc selectivity (78%) of H-MOR-0.15Na was nearly 2.5 times more than that of untreated H-MOR (31%). However, H-MOR-Py showed almost no carbonylation activity (<1% MMAc) and a highest DME selectivity (98%), indicating that Brønsted acid sites in 12-MR were the only active sites for DMM carbonylation, whereas those in 8-MR tended to accelerate DMM disproportionation to DME.
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
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