Catalytic consequences of Ga promotion on Cu for CO2 hydrogenation to methanol

2017 ◽  
Vol 7 (15) ◽  
pp. 3375-3387 ◽  
Author(s):  
Juan C. Medina ◽  
Manuel Figueroa ◽  
Raydel Manrique ◽  
Jhonatan Rodríguez Pereira ◽  
Priya D. Srinivasan ◽  
...  
Keyword(s):  
Active Sites ◽  
Co2 Hydrogenation

The addition of Ga to Cu/SiO2 generates new active sites increasing selectivity to methanol. The mechanistic implications are studied by in situ DRIFTS and kinetic experiments.

scholarly journals Electrokinetic and in situ spectroscopic investigations of CO electrochemical reduction on copper

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jing Li ◽  
Xiaoxia Chang ◽  
Haochen Zhang ◽  
Arnav S. Malkani ◽  
Mu-jeng Cheng ◽  
...  
Keyword(s):  
Mass Transport ◽  
Active Sites ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Adsorbed Hydrogen ◽  
Diffusion Type ◽  
Proton Coupled Electron Transfer ◽  
Alkaline Electrolytes ◽  
Reaction Orders

AbstractRigorous electrokinetic results are key to understanding the reaction mechanisms in the electrochemical CO reduction reaction (CORR), however, most reported results are compromised by the CO mass transport limitation. In this work, we determined mass transport-free CORR kinetics by employing a gas-diffusion type electrode and identified dependence of catalyst surface speciation on the electrolyte pH using in-situ surface enhanced vibrational spectroscopies. Based on the measured Tafel slopes and reaction orders, we demonstrate that the formation rates of C2+ products are most likely limited by the dimerization of CO adsorbate. CH4 production is limited by the CO hydrogenation step via a proton coupled electron transfer and a chemical hydrogenation step of CO by adsorbed hydrogen atom in weakly (7 < pH < 11) and strongly (pH > 11) alkaline electrolytes, respectively. Further, CH4 and C2+ products are likely formed on distinct types of active sites.

scholarly journals Synergistic Effect of Alkali Na and K Promoter on Fe-Co-Cu-Al Catalysts for CO2 Hydrogenation to Light Hydrocarbons

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 735
Author(s):  
Yuhao Zheng ◽  
Chenghua Xu ◽  
Xia Zhang ◽  
Qiong Wu ◽  
Jie Liu
Keyword(s):  
Synergistic Effect ◽  
Active Sites ◽  
Intermediate Formation ◽  
Active Phase ◽  
Dissociative Adsorption ◽  
Co2 Hydrogenation ◽  
Chain Growth ◽  
Co2 Conversion ◽  
Light Hydrocarbons ◽  
Active Centers

Alkali metal K- and/or Na-promoted FeCoCuAl catalysts were synthesized by precipitation and impregnation, and their physicochemical and catalytic performance for CO2 hydrogenation to light hydrocarbons was also investigated in the present work. The results indicate that Na and/or K introduction leads to the formation of active phase metallic Fe and Fe-Co crystals in the order Na < K < K-Na. The simultaneous introduction of Na and K causes a synergistic effect on increasing the basicity and electron-rich property, promoting the formation of active sites Fe@Cu and Fe-Co@Cu with Cu0 as a crystal core. These effects are advantageous to H2 dissociative adsorption and CO2 activation, giving a high CO2 conversion with hydrogenation. Moreover, electron-rich Fe@Cu (110) and Fe-Co@Cu (200) provide active centers for further H2 dissociative adsorption and O-C-Fe intermediate formation after adsorption of CO produced by RWGS. It is beneficial for carbon chain growth in C2+ hydrocarbons, including olefins and alkanes. FeCoCuAl simultaneously modified by K-Na exhibits the highest CO2 conversion and C2+ selectivity of 52.87 mol% and 89.70 mol%, respectively.

Diffuse Reflectance FT-IR Characterization of Active Sites under Reaction Conditions: The Production of Oxygenates in the CO/H2 Reaction

1994 ◽  
Vol 48 (10) ◽  
pp. 1208-1212 ◽  
Author(s):  
J. J. Benítez ◽  
I. Carrizosa ◽  
J. A. Odriozola
Keyword(s):  
Infrared Spectra ◽  
Active Sites ◽  
Diffuse Reflectance ◽  
Reaction Conditions ◽  
In Situ Drifts ◽  
Ft Ir

The reactivity of a Lu2O3-promoted Rh/Al2O3 catalyst in the CO/H2 reaction is reported. Methane, heavier hydrocarbons, methanol, and ethanol are obtained. In situ DRIFTS has been employed to record the infrared spectra under the actual reaction conditions. The structure of the observed COads DRIFTS bands has been resolved into its components. The production of oxygenates (methanol and ethanol) has been correlated with the results of the deconvolution calculation. Specific sites for the production of methanol and ethanol in the CO/H2 reaction over a Rh,Lu2O3/Al2O3 catalyst are proposed.

Construction of Hierarchical ZnIn2S4/C3N4 Heterojunction for Enhanced Photocatalytic Degradation of Tetracycline

2022 ◽  
Author(s):  
Feng Min ◽  
Zhengqing Wei ◽  
Zhen Yu ◽  
Yu-Ting Xiao ◽  
Shien Guo ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Organic Contaminants ◽  
Charge Separation ◽  
Active Sites ◽  
In Situ Growth ◽  
Efficient Charge

Both efficient charge separation and sufficiently exposed active sites are critical limiting for solar-driven organic contaminants degradation. Herein, we describe a hierarchical heterojunction photocatalyst fabricated by in situ growth of...

Electrochemically controlled in-situ conversion of CO2 to defective carbon nanotubes for enhanced H2O2 production

Nanoscale ◽  
2021 ◽  
Author(s):  
Ao Yu ◽  
Guoming Ma ◽  
Longtao Zhu ◽  
Yajing Hu ◽  
Ruiling Zhang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Active Sites ◽  
Catalytic Reactions ◽  
H2o2 Production

Defects on carbon nanotubes (CNTs) can be used as active sites to promote the occurrence of catalytic reactions and improve the ability of catalysts. Although some progress has been made...

scholarly journals Visualization of Active Sites of Nanoporous Metal Catalyst by in-situ TEM Observation

Materia Japan ◽  
2016 ◽  
Vol 55 (12) ◽  
pp. 589-589
Author(s):  
Takeshi Fujita ◽  
Mingwei Chen ◽  
Tomoharu Tokunaga ◽  
Yuta Yamamoto ◽  
Shigeo Arai ◽  
...  
Keyword(s):  
Active Sites ◽  
Metal Catalyst ◽  
Nanoporous Metal

Photocatalytic reforming of glycerol for H2 evolution on Pt/TiO2: fundamental understanding the effect of co-catalyst Pt and the Pt deposition route

2015 ◽  
Vol 3 (5) ◽  
pp. 2271-2282 ◽  
Author(s):  
Xiaoliang Jiang ◽  
Xianliang Fu ◽  
Li Zhang ◽  
Sugang Meng ◽  
Shifu Chen
Keyword(s):  
Active Sites ◽  
H2 Evolution ◽  
Co Catalyst ◽  
Fundamental Understanding

The effects of deposited Pt and its deposition route on the photocatalytic reforming of glycerol for H2 evolution over Pt/TiO2 were investigated. Intimately loaded Pt(0) particles are the key active sites for the reaction, the formation of which was favored by an in situ photo-deposition route.

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