New Nickel-Copper Catalyst Converts Ethanol to Synthesis Gas with High Efficiency
Scientists have developed a stable nickel-based catalyst with a copper admixture capable of converting ethanol into synthesis gas with 95% efficiency. This process, which utilizes ethanol produced from carbon dioxide, offers a potential solution for reducing greenhouse gases while producing synthesis gas used in chemical production and power generation. The study, supported by the Russian Science Foundation, was published in The Journal of Physical Chemistry C.
Reducing greenhouse gases like carbon dioxide and methane in the atmosphere has led scientists to explore technologies for converting them into valuable chemicals. One such approach involves transforming carbon dioxide into ethanol, which can then be converted into synthesis gas—a mixture of hydrogen and carbon monoxide widely used in electricity generation and industrial processes. However, the nickel-based catalysts typically used for this conversion often suffer efficiency losses due to sintering (when particles stick together) and carbon buildup during the reaction.
Researchers from the Patrice Lumumba Peoples' Friendship University of Russia have now addressed these issues by developing a sintering-resistant catalyst. They achieved this by adding a small amount of copper (1%, 10%, or 50%) to the nickel catalyst, creating a bimetallic system. This bimetallic catalyst was then applied to a substrate composed of aluminum, zirconium, and cerium oxides, which prevented carbon deposition on the catalyst's surface.
The researchers compared the performance of their new catalyst with that of traditional single-metal catalysts by heating a mixture of ethanol and carbon dioxide to 650°C for seven hours. Throughout this process, sensors recorded the reaction products. The results showed that adjusting the copper content and modifying the substrate composition allowed for precise control of the ratio of hydrogen to carbon monoxide in the produced synthesis gas.
For example, adding just 1% copper to the nickel catalyst resulted in synthesis gas enriched with hydrogen, achieving a conversion efficiency of 95%. The hydrogen share in the mixture varied from 55% to 68%, depending on the substrate composition, whereas traditional nickel catalysts typically produced a 50-50 mix of hydrogen and carbon monoxide.
The stability of the new catalyst was also impressive, with only a slight decrease in activity (5-10%) observed during the reaction period. This demonstrates the high durability of the nickel-copper catalyst under high temperatures, a crucial factor for practical applications.
"Our studies have shown that adding a small amount of copper to a nickel catalyst allows it to retain its activity at high temperatures by preventing the nanoparticles from sticking together," said Anna Zhukova, PhD, Associate Professor and Lead Researcher at the Patrice Lumumba Russian Academy of Sciences. "The bimetallic system and metal oxide substrate also prevent carbon buildup, making this catalyst ideal for reducing greenhouse gases and generating valuable chemical products. In the future, we plan to test our catalysts in multiple operational cycles and explore their application in processing other compounds, such as glycerol and methane."
