Simultaneously adsorption, activation and in-situ reduction of carbon dioxide over Au loading BiOCl with rich oxygen vacancies

Nanoscale ◽  
2021 ◽  
Author(s):  
Yi-lei Li ◽  
Ying Liu ◽  
Hui-Ying Mu ◽  
Rui-hong Liu ◽  
ying-juan hao ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Electron Transfer ◽  
Active Sites ◽  
Oxygen Vacancies ◽  
Main Process ◽  
In Situ Reduction ◽  
Co2 Photoreduction ◽  
Carbon Dioxide Co2

The main process of carbon dioxide (CO2) photoreduction is that the excited electrons are transported to the surfaced active sites to reduce the adsorbed CO2 molecules. Obviously, electron transfer to...

scholarly journals On the Mechanism of Carbon Dioxide Reduction on Sn-Based Electrodes: Insights into the Role of Oxide Surfaces

Catalysts ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 636 ◽  
Author(s):  
Giane B. Damas ◽  
Caetano R. Miranda ◽  
Ricardo Sgarbi ◽  
James M. Portela ◽  
Mariana R. Camilo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Electron Transfer ◽  
Formic Acid ◽  
Oxide Layer ◽  
Co2 Reduction ◽  
Carbon Dioxide Reduction ◽  
Oxide Surfaces ◽  
In Situ Conditions

The electrochemical reduction of carbon dioxide into carbon monoxide, hydrocarbons and formic acid has offered an interesting alternative for a sustainable energy scenario. In this context, Sn-based electrodes have attracted a great deal of attention because they present low price and toxicity, as well as high faradaic efficiency (FE) for formic acid (or formate) production at relatively low overpotentials. In this work, we investigate the role of tin oxide surfaces on Sn-based electrodes for carbon dioxide reduction into formate by means of experimental and theoretical methods. Cyclic voltammetry measurements of Sn-based electrodes, with different initial degree of oxidation, result in similar onset potentials for the CO2 reduction to formate, ca. −0.8 to −0.9 V vs. reversible hydrogen electrode (RHE), with faradaic efficiencies of about 90–92% at −1.25 V (vs. RHE). These results indicate that under in-situ conditions, the electrode surfaces might converge to very similar structures, with partially reduced or metastable Sn oxides, which serve as active sites for the CO2 reduction. The high faradaic efficiencies of the Sn electrodes brought by the etching/air exposition procedure is ascribed to the formation of a Sn oxide layer with optimized thickness, which is persistent under in situ conditions. Such oxide layer enables the CO2 “activation”, also favoring the electron transfer during the CO2 reduction reaction due to its better electric conductivity. In order to elucidate the reaction mechanism, we have performed density functional theory calculations on different slab models starting from the bulk SnO and Sn6O4(OH)4 compounds with focus on the formation of -OH groups at the water-oxide interface. We have found that the insertion of CO2 into the Sn-OH bond is thermodynamically favorable, leading to the stabilization of the tin-carbonate species, which is subsequently reduced to produce formic acid through a proton-coupled electron transfer process. The calculated potential for CO2 reduction (E = −1.09 V vs. RHE) displays good agreement with the experimental findings and, therefore, support the CO2 insertion onto Sn-oxide as a plausible mechanism for the CO2 reduction in the potential domain where metastable oxides are still present on the Sn surface. These results not only rationalize a number of literature divergent reports but also provide a guideline for the design of efficient CO2 reduction electrocatalysts.

scholarly journals A Fiber-Integrated CRDS Sensor for In-Situ Measurement of Dissolved Carbon Dioxide in Seawater

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6436
Author(s):  
Mai Hu ◽  
Bing Chen ◽  
Lu Yao ◽  
Chenguang Yang ◽  
Xiang Chen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Equilibrium Condition ◽  
Co2 Concentration ◽  
Scientific Data ◽  
In Situ Measurement ◽  
Integrated Sensor ◽  
Dissolved Carbon ◽  
Low Efficiency ◽  
Carbon Dioxide Co2

Research on carbon dioxide (CO2) geological and biogeochemical cycles in the ocean is important to support the geoscience study. Continuous in-situ measurement of dissolved CO2 is critically needed. However, the time and spatial resolution are being restricted due to the challenges of very high submarine pressure and quite low efficiency in water-gas separation, which, therefore, are emerging the main barriers to deep sea investigation. We develop a fiber-integrated sensor based on cavity ring-down spectroscopy for in-situ CO2 measurement. Furthermore, a fast concentration retrieval model using exponential fit is proposed at non-equilibrium condition. The in-situ dissolved CO2 measurement achieves 10 times faster than conventional methods, where an equilibrium condition is needed. As a proof of principle, near-coast in-situ CO2 measurement was implemented in Sanya City, Haina, China, obtaining an effective dissolved CO2 concentration of ~950 ppm. The experimental results prove the feasibly for fast dissolved gas measurement, which would benefit the ocean investigation with more detailed scientific data.

Visualizing and Quantifying Generation, Propagation, and Sweep of Nanocellulose-Strengthened Carbon Dioxide Foam in a Complex 2D Heterogeneous Fracture Network Model

SPE Journal ◽  
2021 ◽  
pp. 1-14
Author(s):  
Bing Wei ◽  
Qingtao Tian ◽  
Shengen Chen ◽  
Xingguang Xu ◽  
Dianlin Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Network Model ◽  
Gravitational Effect ◽  
Fracture Network ◽  
Sweep Efficiency ◽  
Co2 Foam ◽  
Reservoir Conditions ◽  
Foam Film ◽  
Carbon Dioxide Co2

Summary There exist two main issues hampering the wide application and development of carbon dioxide (CO2) foam in conformance improvement and CO2 mobility reduction in fractured systems: (1) instability of foam film under reservoir conditions and (2) uncertainties of foam flow in complex fractures. To address these two issues, we previously developed a series of nanocellulose-strengthened CO2 foam (referred to as NCF-st-CO2 foam), while the primary goal of this work is to thoroughly elucidate generation, propagation, and sweep of NCF-st-CO2 foam in a visual 2D heterogeneous fracture network model. NCF-st-CO2 foam outperformed CO2 foam in reducing gas mobility during either coinjection (COI) or surfactant-alternating-gas (SAG) injection, and the threshold foam quality was approximately 0.67. Foam creation was increased with the total superficial velocity for CO2 foam and almost stayed constant for NCF-st-CO2 foam in fractures during COI. For SAG, large surfactant slug could prevent CO2 from early breakthrough and facilitate foaming in situ. The improved sweep efficiency induced by NCF-st-CO2 foam occurred near the producer for both COI and SAG. Film division and behind mainly led to foam generation in the fracture model. Gravity segregation and override was insignificant during COI but became noticeable during SAG, which caused the sweep efficiency decrease by 3 to 9%. Owing to the enhanced film, NCF-st-CO2 foam enabled mitigation of the gravitational effect, especially around the producer.

Investigation on Foam Self-Generation Using In Situ Carbon Dioxide (CO2 ) for Enhancing Oil Recovery

2018 ◽  
Vol 21 (3) ◽  
pp. 399-408 ◽  
Author(s):  
Fayang Jin ◽  
Peng Wei ◽  
Wanfen Pu ◽  
Lan Zhang ◽  
Zhen Qian ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oil Recovery ◽  
Carbon Dioxide Co2

scholarly journals Evolution of anatase surface active sites probed by in situ sum-frequency phonon spectroscopy

2016 ◽  
Vol 2 (9) ◽  
pp. e1601162 ◽  
Author(s):  
Yue Cao ◽  
Shiyou Chen ◽  
Yadong Li ◽  
Yi Gao ◽  
Deheng Yang ◽  
...  
Keyword(s):  
Active Sites ◽  
Oxygen Vacancies ◽  
Surface Reactivity ◽  
Ambient Conditions ◽  
Sum Frequency ◽  
Surface Active ◽  
Surface Phonon Mode ◽  
Titanium Dioxides ◽  
Associated Species

Surface active sites of crystals often govern their relevant surface chemistry, yet to monitor them in situ in real atmosphere remains a challenge. Using surface-specific sum-frequency spectroscopy, we identified the surface phonon mode associated with the active sites of undercoordinated titanium ions and conjoint oxygen vacancies, and used it to monitor them on anatase (TiO2) (101) under ambient conditions. In conjunction with theory, we determined related surface structure around the active sites and tracked the evolution of oxygen vacancies under ultraviolet irradiation. We further found that unlike in vacuum, the surface oxygen vacancies, which dominate the surface reactivity, are strongly regulated by ambient gas molecules, including methanol and water, as well as weakly associated species, such as nitrogen and hydrogen. The result revealed a rich interplay between prevailing ambient species and surface reactivity, which can be omnipresent in environmental and catalytic applications of titanium dioxides.

SET-LRP of NIPAM in water via in situ reduction of Cu(ii) to Cu(0) with NaBH4

2016 ◽  
Vol 7 (4) ◽  
pp. 933-939 ◽  
Author(s):  
Mikhail Gavrilov ◽  
Timothy J. Zerk ◽  
Paul V. Bernhardt ◽  
Virgil Percec ◽  
Michael J. Monteiro
Keyword(s):  
Electron Transfer ◽  
Radical Polymerization ◽  
Living Radical Polymerization ◽  
Water Soluble ◽  
New Method ◽  
Single Electron Transfer ◽  
In Situ Reduction ◽  
Water Soluble Polymers ◽  
Soluble Polymers

The direct and quantitative reduction of the air-stable Cu(ii)Br2/Me6TREN to Cu(0) by NaBH4 represents a new method for the aqueous single electron transfer-living radical polymerization (SET-LRP) of water soluble polymers.

scholarly journals In Situ Studies of the Active Sites for the Water Gas Shift Reaction over Cu−CeO2Catalysts:  Complex Interaction between Metallic Copper and Oxygen Vacancies of Ceria

2006 ◽  
Vol 110 (1) ◽  
pp. 428-434 ◽  
Author(s):  
Xianqin Wang ◽  
José A. Rodriguez ◽  
Jonathan C. Hanson ◽  
Daniel Gamarra ◽  
Arturo Martínez-Arias ◽  
...  
Keyword(s):  
Active Sites ◽  
Oxygen Vacancies ◽  
Metallic Copper ◽  
Complex Interaction ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
In Situ Studies ◽  
Shift Reaction ◽  
Water Gas
Sign in / Sign up

Export Citation Format

Share Document