scholarly journals Enhancing CO2 Conversion to CO over Plasma-Deposited Composites Based on Mixed Co and Fe Oxides

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 883
Author(s):  
Hanna Kierzkowska-Pawlak ◽  
Małgorzata Ryba ◽  
Maciej Fronczak ◽  
Ryszard Kapica ◽  
Jan Sielski ◽  
...  

The hydrogenation of CO2 to produce CO and H2O, known as reverse-water-gas shift reaction (RWGS) is considered to be an important CO2 valorization pathway. This work is aimed at proposing the thin-film catalysts based on iron and cobalt oxides for this purpose. A series of Fe–Co nanocomposites were prepared by the plasma-enhanced chemical vapor deposition (PECVD) from organic cobalt and iron precursors on a wire-mesh support. The catalysts were characterized by SEM/EDX, XPS, XRD, and Raman spectroscopy and studied for hydrogenation of CO2 in a tubular reactor operating in the temperature range of 250–400 °C and atmospheric pressure. The Co-based catalyst, containing crystalline CoO phase, exhibited high activity toward CH4, while the Fe-based catalyst, containing crystalline Fe2O3/Fe3O4 phases, was less active and converted CO2 mainly into CO. Regarding the Fe–Co nanocomposites (incl. Fe2O3/Fe3O4 and CoO), even a small fraction of iron dramatically inhibited the production of methane. With increasing the atomic fraction of iron in the Fe–Co systems, the efficiency of the RWGS reaction at 400 °C increased up to 95% selectivity to CO and 30% conversion of CO2, which significantly exceeded the conversion for pure iron–based films (approx. 9%). The superior performance of the Fe–Co nanocomposites compared to “pure” Co and Fe–based films was proposed to be explained by assuming changes in the electronic structure of the catalyst resulting from the formation of p–n junctions between nanoparticles of cobalt and iron oxides.

Author(s):  
Daiya Kobayashi ◽  
Hirokazu Kobayashi ◽  
Kohei Kusada ◽  
Tomokazu Yamamoto ◽  
Takaaki Toriyama ◽  
...  

We report PtW solid-solution alloy nanoparticles (NPs) as a reverse water-gas shift (RWGS) reaction catalyst for the first time. Atomic-level alloying of Pt and W significantly enhanced the RWGS reaction activity of Pt NPs.


Author(s):  
Miriam González-Castaño ◽  
Bogdan Dorneanu ◽  
Harvey Arellano-García

RWGS reaction thermodynamics, mechanisms and kinetics. Process design and process intensification – from lab scale to industrial applications and CO2 value chains. Pathways for further improvement of catalytic systems, reactor and process design.


1995 ◽  
Vol 10 (2) ◽  
pp. 425-430 ◽  
Author(s):  
W. Zhu ◽  
F.R. Sivazlian ◽  
B.R. Stoner ◽  
J.T. Glass

This paper describes a process for uniformly enhancing the nucleation density of diamond films on silicon (Si) substrates via dc-biased hot filament chemical vapor deposition (HFCVD). The Si substrate was negatively biased and the tungsten (W) filaments were positively biased relative to the grounded stainless steel reactor wall. It was found that by directly applying such a negative bias to the Si substrate in a typical HFCVD process, the enhanced diamond nucleation occurred only along the edges of the Si wafer. This resulted in an extremely nonuniform nucleation pattern. Several modifications were introduced to the design of the substrate holder, including a metal wire-mesh inserted between the filaments and the substrate, in the aim of making the impinging ion flux more uniformly distributed across the substrate surface. With such improved growth system designs, uniform enhancement of diamond nucleation across the substrate surface was realized. In addition, the use of certain metallic wire mesh sizes during biasing also enabled patterned or selective diamond deposition.


Nanoscale ◽  
2019 ◽  
Vol 11 (35) ◽  
pp. 16677-16688 ◽  
Author(s):  
Yulian He ◽  
Ke R. Yang ◽  
Ziwei Yu ◽  
Zachary S. Fishman ◽  
Laura A. Achola ◽  
...  

We develop efficient synthetic methods to prepare various MnO2 structures and investigate their structure–property relationships as applied to the reverse Water Gas Shift (rWGS) reaction with a combination of experimental and theoretical tools.


RSC Advances ◽  
2020 ◽  
Vol 10 (17) ◽  
pp. 10285-10296
Author(s):  
Nicky Bogolowski ◽  
Beatriz Sánchez Batalla ◽  
Baekkyoung Shin ◽  
Jean-Francois Drillet

LSCrM, Ni3Sn2 and GDC20 powders show high activity and selectivity for the RWGS reaction.


1991 ◽  
Vol 250 ◽  
Author(s):  
W. Halverson ◽  
G. D. Vakerlis ◽  
D. Garg ◽  
P. N. Dyer

AbstractPlasma-assisted chemical vapor deposition (PACVD) is used extensively to coat planar (2-dimensional) substrates. In principle, the technique can be used to deposit coatings on 3-dinensional objects. However, extending PACVD to coat 3-dimensional objects uniformly requires careful control of the plasma, substrate temperature, and reactant concentrations over a large volume. A novel low-temperature radio frequency PACVD reactor design was developed to deposit coatings uniformly and reproducibly on 3-dimensional metallic substrates. The design features a temperature-controlled reaction chamber fitted with one or more rf-driven electrodes to generate uniform, large-volume plasma. The reactor was used to develop a series of silicon carbide coatings, which were deposited at or below 500°C. The coatings contain SiC and varying amounts of free silicon and/or amorphous carbon (diamond-like carbon), depending on reagent gas composition and reactor operating parameters. The coatings significantly reduced wear on stainless steel samples in ball-on-disk and abrasive wear tests and provided oxidation protection to molybdenum and titanium alloy.


2015 ◽  
Vol 2 (8) ◽  
pp. 741-748 ◽  
Author(s):  
Baowang Lu ◽  
Yiwen Ju ◽  
Takayuki Abe ◽  
Katsuya Kawamoto

Bimetallic oxides could be well distributed on the SBA-15 surface, and exhibited high catalytic perforation for RWGS reaction.


Author(s):  
Shinya Mine ◽  
Taichi Yamaguchi ◽  
Kah Wei Ting ◽  
Zen Maeno ◽  
S. M. A. Hakim Siddiki ◽  
...  

The reverse water-gas shift (RWGS) reaction is a promising catalytic route for reducing CO2 emissions because its product, CO, is a key intermediate in various industrialized catalytic processes that produce...


MRS Advances ◽  
2018 ◽  
Vol 3 (18) ◽  
pp. 937-942
Author(s):  
Chi-Chin Wu ◽  
Timothy A. Jenkins ◽  
James K. Hirvonen ◽  
Michael Leadore

ABSTRACTAn investigation of the effect of experimental parameters on the temperature and uniformity of material deposition by atmospheric pressure dielectric barrier discharge (DBD) planar plasma reactors was conducted. The apparatus consisted of a pulsed AC high voltage power source with various electrode materials (aluminum, copper wire mesh, and aluminum/copper wire mesh) operating under a range of load resistances. Possible effects of non-ideal interfacial conditions for the contact surface between the electrode and the substrate were also studied with various modified surface thermal conditions. It was found that a hybrid electrode design with a fine copper (Cu) wire mesh attached to an aluminum plate of approximately 3 mm thickness produced the most visually uniform deposit, presumably as a result of both the superior conductivity provided by the Al metal plate and the stable plasma resulting from the relatively low breakdown voltage by using helium (He) as the dilution gas. Although the experimental conditions of plasma-enhanced chemical vapor deposition (PECVD) are often specific to particular systems and applications, this work provides insights on technical details which can be applied to various plasma DBD reactors.


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