Abstract
An essential problem in managing CO2 and transforming it into methane as a useful fuel is the quest for adequately efficient and cheap catalysts. Another condition is imposed by the new designs of structured reactors, which require catalysts in the form of the thinnest possible films. The aim of this work was to produce Ni-based thin-film catalysts by the cold plasma deposition method (PECVD) from a volatile metal complex (Ni(CO)4) and to study their structure and catalytic properties in the CO2 methanation process. We tested three basic types of films: as-deposited, calcined in Ar, and calcined in air. The nanostructure and molecular structure of the films were investigated by electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The catalytic activity was evaluated in the methanation process (CO2 + H2), which was performed in a tubular reactor operating in the temperature range of 300–400 °C. The films calcined in air showed the highest activity in this process but behaved unstably. However, their regeneration by recalcination in air restored the initial catalytic activity. An important conclusion emerged from the obtained results, namely that the active phase in the tested films is Ni3+ (most likely in the form of Ni2O3), contrary to the common opinion that this phase is metallic Ni0. In our case, Ni0 quenches the catalytic activity.
Highlights
The main advantage of this type of catalytic materials is their thin-film nature and the possibility of deposition on supports of virtually any shape without changing their original geometry, which is extremely useful in the construction of structured packings for chemical reactors [4]
The catalytic films were deposited by the PECVD method from Ni(CO)4 on a support made of kanthal steel covered with a layer of Al2 O3 by high-temperature calcination
The Ni-based films were produced by cold plasma deposition (PECVD) in a parallelplate frequency
Summary
The technology for the production of thin films using the cold plasma deposition method (PECVD) has opened the possibility of obtaining a completely new generation of catalytic materials with wide prospects for their application in various chemical and photoelectrochemical processes [1,2,3]. The main advantage of this type of catalytic materials is their thin-film nature (thickness from several tens of nm to several μm) and the possibility of deposition on supports of virtually any shape without changing their original geometry, which is extremely useful in the construction of structured packings for chemical reactors [4]. Not without significance is the relatively easy and precise control of the molecular structure and nanostructure of such films, which is realized in a wide range by selecting the appropriate plasma precursors and the conditions of the production process [5,6]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
