Hokkaido University researchers have created an improved catalyst for the conversion of methane gas into syngas, a precursor for liquid fuels and fundamental chemicals.
Syngas, also known as synthesis gas, is a mixture made primarily of carbon monoxide and hydrogen and is used to manufacture polymers, pharmaceuticals, and synthetic petroleum. It is made by exposing methane to water vapor at 900 °C or higher, making the process costly.
The proposed mechanism in which the hydrogen atoms spill over onto zeolite support, which then turns the cobalt oxide back into cobalt, keeping the catalyst active.
Credit: Yuhui Hou et al., Communications Chemistry, August 1, 2018
Usage Restrictions: This image is copyrighted and can be used for reporting this press release if properly credited.
The partial oxidation of methane for syngas synthesis is more economical than using steam but there have been issues with the catalysts used for this process. Noble metal catalysts, such as rhodium and platinum, are better and work at lower temperatures than base metal catalysts, such as cobalt and nickel, but they are also more expensive.
The cheaper base metal catalysts require temperatures above 800 °C, exceeding the temperature range for industrial stainless-steel reactors. They are also deactivated during the reaction by re-oxidation and the accumulation of coke, a by-product of the process, making them costly in the long-term.
Assistant Professor Hirokazu Kobayashi, Professor Atsushi Fukuoka, and postdoctoral fellow Yuhui Hou, working in Hokkaido University's Institute for Catalysis, succeeded in preparing a catalyst that combines the properties of both noble and base metals. Their catalyst overcomes challenges faced by previous studies in adding a small enough amount of noble metal to the base metal catalyst that it can still work at lower temperatures.
In the study published in Communications Chemistry, the team successfully generated tiny particles of the base metal cobalt by dispersing them onto a mineral deposit called zeolite. They then added a minute amount of noble metal rhodium atoms onto the cobalt particles.
The new, combined catalyst successfully converted 86% of methane to syngas at 650 °C while maintaining its activity for at least 50 hours. The reaction oxidizes cobalt to cobalt oxide, which is nearly inactive. But because the rhodium is contained, the noble metal generates hydrogen atoms from methane or hydrogen molecules.
The hydrogen atoms spill over onto the supporting material, and the spillover hydrogen turns the cobalt oxide back into cobalt. The cobalt can then continue to act as a catalyst. The high dispersion of cobalt on zeolite also prevented the formation of coke during the reaction.
Methane has drawn attention as a source of clean energy as it produces only a half amount of CO2 compared to petroleum when burned. Moreover, increased shale gas mining has made methane a more accessible resource.
"Our catalyst can efficiently convert methane to syngas at 650 °C, a much lower temperature than in conventional methods. This could lead to more efficient use of methane and contribute to the development of a low-carbon society," says Hirokazu Kobayashi.
Naoki Namba | EurekAlert!
To improve auto coatings, new tests do more than scratch the surface
21.09.2018 | National Institute of Standards and Technology (NIST)
World's first passive anti-frosting surface fights ice with ice
18.09.2018 | Virginia Tech
The building blocks of matter in our universe were formed in the first 10 microseconds of its existence, according to the currently accepted scientific picture. After the Big Bang about 13.7 billion years ago, matter consisted mainly of quarks and gluons, two types of elementary particles whose interactions are governed by quantum chromodynamics (QCD), the theory of strong interaction. In the early universe, these particles moved (nearly) freely in a quark-gluon plasma.
This is a joint press release of University Muenster and Heidelberg as well as the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt.
Then, in a phase transition, they combined and formed hadrons, among them the building blocks of atomic nuclei, protons and neutrons. In the current issue of...
Thin-film solar cells made of crystalline silicon are inexpensive and achieve efficiencies of a good 14 percent. However, they could do even better if their shiny surfaces reflected less light. A team led by Prof. Christiane Becker from the Helmholtz-Zentrum Berlin (HZB) has now patented a sophisticated new solution to this problem.
"It is not enough simply to bring more light into the cell," says Christiane Becker. Such surface structures can even ultimately reduce the efficiency by...
A study in the journal Bulletin of Marine Science describes a new, blood-red species of octocoral found in Panama. The species in the genus Thesea was discovered in the threatened low-light reef environment on Hannibal Bank, 60 kilometers off mainland Pacific Panama, by researchers at the Smithsonian Tropical Research Institute in Panama (STRI) and the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR) at the University of Costa Rica.
Scientists established the new species, Thesea dalioi, by comparing its physical traits, such as branch thickness and the bright red colony color, with the...
Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets.
An international team of researchers has mapped Nemo's genome, providing the research community with an invaluable resource to decode the response of fish to...
03.09.2018 | Event News
27.08.2018 | Event News
17.08.2018 | Event News
21.09.2018 | Trade Fair News
21.09.2018 | Earth Sciences
21.09.2018 | Health and Medicine