One-step catalyst synthesis converts carbon dioxide into useful methane

Carbon dioxide is often described as a waste product, but researchers are developing increasingly practical ways to turn it into something useful. A team from the Institute of Science Tokyo, working with collaborators at Nagoya University and the Japan Synchrotron Radiation Research Institute, has created a faster and more scalable route for manufacturing catalysts that convert carbon dioxide and hydrogen into methane. The process could help address one of the central challenges in carbon-utilization technology: producing high-performance catalysts without relying on complicated, expensive preparation procedures.

The work focuses on carbon dioxide methanation, a chemical reaction in which carbon dioxide reacts with hydrogen to form methane and water. Methane can be used as a fuel and as a raw material for chemical manufacturing, and it can be transported through much of the existing natural-gas infrastructure. If the hydrogen is produced using renewable electricity and the carbon dioxide is captured from industrial emissions or directly from the atmosphere, methanation could become part of a strategy for storing renewable energy and recycling carbon. However, the environmental value of this approach depends heavily on the efficiency of the reaction and the sustainability of the energy used to drive it.

At the heart of the process is a catalyst made from nickel and cerium oxide, written chemically as Ni/CeO₂. Catalysts accelerate chemical reactions without being consumed, and nickel is widely studied for methanation because it is considerably less expensive than precious metals such as ruthenium. Its performance, however, depends on how the nickel is distributed across the supporting material. Small, well-dispersed nickel particles expose more active surface area, while the interaction between nickel and cerium oxide can improve the movement and activation of oxygen-containing species involved in the reaction.

The researchers produced their catalyst using flame-assisted spray pyrolysis, or FASP, a one-step manufacturing technique that combines atomized droplets with a high-temperature flame. In the process, a solution containing the chemical ingredients of the catalyst is sprayed into the flame. As the tiny droplets travel through the hot reaction zone, the solvent evaporates and the dissolved compounds undergo rapid thermal transformation, forming solid catalyst particles. Because synthesis, drying, and particle formation occur in a single continuous operation, FASP can avoid several separate steps required by conventional catalyst-preparation methods.

The team used a diffusion-flame FASP system to create Ni/CeO₂ and compared the resulting material with a catalyst prepared using impregnation, one of the most common methods in the field. Impregnation generally involves depositing a nickel-containing solution onto a support, drying the material, and then carrying out additional heat treatments to obtain the desired catalyst structure. Such procedures can offer good control, but they may also be time-consuming and difficult to transfer efficiently from laboratory-scale batches to industrial production. The flame-based approach was designed to simplify this manufacturing pathway while preserving the fine structure needed for strong catalytic activity.

To understand why the flame-synthesized material performed well, the researchers examined its physical and chemical structure using several advanced analytical techniques. Field-emission scanning electron microscopy revealed finer and more uniformly distributed nanoparticles. This type of morphology is important because a catalyst’s performance is governed not only by its chemical composition but also by the size, location, and accessibility of its active sites. Smaller particles can provide a larger reactive surface, while uniform distribution can reduce the formation of inactive nickel aggregates that limit contact with the cerium oxide support.

X-ray photoelectron spectroscopy and X-ray absorption fine-structure measurements provided additional information about the catalyst’s electronic and atomic environment. The FASP-derived material contained more oxygen vacancies in the cerium oxide structure, as well as a greater proportion of catalytically active reduced nickel species. Oxygen vacancies are missing oxygen atoms within a metal-oxide lattice, and they can influence how carbon dioxide molecules attach to and break apart on the catalyst surface. The researchers also observed more contact points between nickel and cerium oxide, creating interfaces where the two materials can cooperate during the multistep methanation reaction.

Those structural features translated into stronger performance in testing. Across the temperature range examined, the flame-produced catalyst achieved higher carbon dioxide conversion and methane selectivity than the conventionally prepared comparison material. At 300 degrees Celsius, it reached a methane production rate of 81.3 micromoles per gram of catalyst per second. The result is especially notable because the catalyst achieved this level of activity with a relatively low nickel loading, suggesting that the arrangement and chemical state of the nickel may be as important as the total amount used.

The significance of the study extends beyond a single catalyst formulation. Many promising materials for carbon dioxide conversion perform well in carefully controlled laboratory experiments but face obstacles when manufacturers attempt to produce them in large quantities. A one-step flame process could potentially offer continuous operation, rapid particle formation, and easier scale-up than multistage preparation methods. The technology does not by itself solve every challenge associated with synthetic methane, including the need for low-carbon hydrogen, efficient carbon dioxide capture, long-term catalyst stability, and overall energy efficiency. Nevertheless, by combining a relatively simple production route with high catalytic activity, the research offers a practical advance toward more deployable carbon-recycling systems. The findings, reported in the journal Fuel, point to a future in which captured carbon dioxide could be transformed into a storable energy carrier using catalysts manufactured through an industrially adaptable process.

News Publication Date: 8 July 2026

Web References: https://doi.org/10.1016/j.fuel.2026.140563

References: Fuel, Volume 428; DOI: 10.1016/j.fuel.2026.140563

Keywords

Carbon dioxide, methane, CO2 methanation, nickel–cerium oxide catalysts, flame-assisted spray pyrolysis, carbon utilization, synthetic methane, catalysis, renewable energy, sustainability