Scientists at Rice University have discovered a surprisingly simple way to make carbon dioxide–to–fuel technology last much longer and work more reliably—by bubbling the gas through a mild acid.
This technology, called electrochemical CO2 reduction, or CO2RR, uses electricity (ideally from renewable sources like wind or solar) to turn climate-warming carbon dioxide into useful chemicals such as carbon monoxide, ethylene, or alcohol.
These chemicals can then be used to create fuel or in industrial processes, potentially turning a dangerous pollutant into a valuable resource.
However, one big challenge has held this technology back: the systems that carry out the conversion often clog up and break down quickly due to salt buildup.
That’s where the Rice team’s breakthrough comes in. Normally, CO2 is humidified with water before it enters the system.
But that method leads to potassium salts forming and getting stuck in the gas channels inside the device.
These salts block the flow of gas, flood key parts of the system, and cause it to fail in less than 100 hours.
The Rice researchers, led by Professor Haotian Wang, found that using a very small amount of acid vapor instead of water vapor could solve the problem.
By bubbling the carbon dioxide gas through a mild acid—like hydrochloric, formic, or acetic acid—before it enters the device, they created just enough acidic moisture to prevent salt from forming hard crystals. These acid-based salts dissolve more easily and don’t clog the system.
This small change made a huge difference. In lab tests using a silver catalyst, a common material for turning CO2 into carbon monoxide, the system ran smoothly for over 2,000 hours. In a larger, 100-square-centimeter version of the device, it kept working for more than 4,500 hours—over 50 times longer than traditional setups.
Even better, the acid vapor method worked with a variety of catalyst materials, including zinc oxide, copper oxide, and bismuth oxide, which are used to make different types of chemical products. It also worked in larger systems, showing that the technique is scalable. Tests showed that common membranes and materials in the system weren’t damaged by the acid, thanks to the very low concentrations used.
The researchers were even able to watch the difference in real time. In transparent test reactors, they saw salt crystals forming within 48 hours with water-humidified gas, while the acid-treated systems stayed clear for hundreds of hours.
This elegant solution—just switching out water for acid—doesn’t require major redesigns or expensive equipment. It could help make carbon capture and fuel-making technology more reliable, affordable, and ready for real-world use.
