APPLICATIONS OF TECHNOLOGY:
- Integration into (photo)-electrochemical devices for improved efficiency
- Storage of solar energy as fuel and valuable chemicals
- Remote energy and fuel production
- Production of carbon-neutral plastics when connected to an ethylene polymerization reactor
- Improved product conversion efficiencies compared to conventional tandem architectures
- Enhanced reaction control
- Greater catalytic area utilization
(Photo)-electrochemical reduction is a promising technology for reducing atmospheric CO2 levels while simultaneously producing valuable fuels and chemicals. However, reduction of CO2 into molecules containing more than one carbon atom is currently difficult to achieve at high selectivities on a single cathodic electrode. In contrast, dual cathode systems allow for more precise control over tandem reactions, enhancing the selectivity of the process.
Scientists at Berkeley Lab have developed a stacked dual cathode for integration into photo-electrochemical devices for CO2 reduction. The primary layer facilitates the conversion of CO2 to an intermediate product, like carbon monoxide. The intermediate product is then converted, for example, to ethylene, on a secondary layer in the cathode. The secondary layer is separated from the primary layer by a conductive membrane that enables both electronic and ionic conduction but impedes undesired gas crossover between the primary and secondary electrodes. The conductive membrane can be tuned to achieve desirable properties for ionic and electronic conduction. Furthermore, the thickness of the conductive membrane may be adjusted to achieve the desired voltage drop across the membrane.
Through the controlled flow of reactants, this technology is designed to achieve high single-pass conversion efficiencies. The stacked design allows for the full use of the device footprint for each cathode catalyst. This is in contrast to traditional tandem devices with coplanar cathodic surfaces, where the allowed area for each catalyst is substantially less than the total device area. This efficiency in catalyst usage can lead to improved product conversion efficiencies. Furthermore, the technology is designed in a membrane electrode assembly type cell format, which reduces ionic path lengths. This configuration generally leads to higher performance due to the efficient transport of ions within the cell.
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