KIST develops a mixed silver-silica catalyst capable of controlling local pH
Published: 2024-10-23 21:52 Updated: 2024-10-23 21:52
Schematic diagram showing the basic problem of gapless CO₂ electrolysis machines
The Korea Institute of Science and Technology (KIST, President Sang-rok Oh) announced that the team of Dr. Hyeong-seok Oh and Woong-hee Lee from the Clean Energy Research Center developed a mixed silver emitter- controllable silica. Local pH through a reversible silica-hydroxide cycle, inspired by the ‘Cycle of the Earth’.
The result of this research was inspired by the process of balancing carbon dioxide (CO₂) through the carbonate-silicate cycle, known as the Earth’s inorganic carbon cycle. CO₂ is extracted from the atmosphere when weathered minerals are filled and returned to the atmosphere through volcanic activity.
SiO₂ (dissolved silica) is generated as silicate rocks turn out to be carbonate rocks, and the Earth’s temperature is regulated by the levels of CO₂ created in the process of recycling back into rocks silicate through volcanic activity. Silica, the main material in this cycle, was applied in the electrochemical CO₂ conversion reaction.
Among the catalysts applied in CCU technology (capture, use and storage of carbon dioxide), the catalyst has the best performance in converting CO₂ to carbon monoxide (CO), a substance crude for petrochemical products. However, silver catalysts have not yet reached the level of commercialization, since the selectivity for CO is greatly reduced due to the aggregation or aggregation of particles on the surface of the catalyst at high current density.
The research team developed a silver-silica composite catalyst mixed with silica to maintain the silver catalyst’s performance. This catalyst changes pH by allowing hydroxide ions (OH-) formed during the reaction to combine with silica, dissolve as silicate, and precipitate again under neutral conditions. Through this, the problem of performance degradation caused by increasing current density was solved using a chemical approach without changing the physical structure of the catalyst.
The mixed silver-silica catalyst developed by the research team showed selectivity close to 100% even at higher current concentrations, unlike commercial silver catalysts whose carbon monoxide selectivity was down to 60% at a concentration high current.
In addition, the CO₂ CO conversion activity was increased by about 47%, achieving high CO₂ conversion reaction efficiency even at high current density.
The silver-silica mixed catalyst is expected to successfully improve CO₂ reduction performance and stability even at high current densities, greatly increasing the commercial potential of CCU electrochemical CO₂ conversion technology.
Even at high current concentrations, long-term performance can be maintained due to high CO selectivity and reversibility, thus increasing productivity and economic efficiency.
To this end, we plan to optimize a process for the mass production of high-efficiency catalysts and conduct a long-term sustainability verification study for deployment to industrial facilities such as power plants and petrochemical plants.
Director of the Center Oh Hyeong-seok said, “It makes sense because it suggests guidelines for the recycling of catalysts and environmental control strategies for electrochemical systems,” and added, “It will be able to contribute to validation and commercialization electrochemical. systems of the future.”
This research was carried out as a major project of KIST, the Carbon to The results of this research were published as a front cover paper in the international academic journal ‘Energy & Environmental Science’.
Reporter Kim Young-jun [email protected]
