Researchers from Harvard University developed black carbon-based catalysts that reduce CO2 into industrial fuels
A team of researchers from Rowland Institute at Harvard University developed an improved system to use renewable electricity for reducing carbon dioxide (CO2) into carbon monoxide (CO). The system is an upgrade of a system first described in a 2017 paper published in the journal Chem. The old system relied on two electrolyte-filled chambers, with an electrode placed in each chamber. According to the team, the new system is cheaper and relies on high concentrations of CO2 gas and water vapor and can produce around four liters of CO per hour with help of one 10-by-10-centimeter cell. Moreover, the new system overcomes the two main challenges of cost and scalability that were evident in previous approach. The research was published in the journal Joule on November 8, 2018.
In the previous research, the team found that single nickel-atom catalysts are very selective for reducing CO2 to CO. However, the materials were expensive to synthesize and the support used to anchor single nickel atoms was based on graphene, which increases challenges in scaling up for mass production. In the current research, the team used black carbon, which is cheaper than graphene. A process similar to electrostatic attraction enabled to absorb single nickel atoms that are positively charged into defects that are negatively charged in carbon black nanoparticles. The team found that the resulting material was both low-cost and highly selective for CO2 reduction.
The initial system developed in 2017 worked only in a liquid solution as it used an electrode in one chamber to split water molecules into oxygen and protons. The team choose to avoid splitting of water and isolated the catalyst from the solution. Liquid water was replaced with water vapor and high-concentration CO2 gas was introduced. The team used 97% CO2 gas and 3% water vapor and ion exchange membranes were used to help ions move around without liquid water. According to the team, the system delivered 100 milliamps of power as compared to ten milliamps-per-centimeter squared in previous system. According to the researchers, these devices can be connected with coal-fired power plants or other industry that produces CO2.