Ultimate Goal: Minimize overall energy to produce chemicals and fuels without side products using heterogeneous catalysts

Structure Control of Heterogeneous Atomic Catalysts;

We aim to control the surface structure of heterogeneous atomic catalysts and elucidate the structure-performance relation.

Applications;

[1] Fuel cells

Fuel cell is environmentally friendly engine to convert chemicals to electricity. Chemicals such as H₂, CH₄, NH₃ can produce electricity using a proper form of fuel cells. Platinum is one of the most widely used catalysts for fuel cell for hydrogen oxidation or oxygen reduction reactions, and we are trying to minimize Pt use by developing highly active catalysts. Various nano-structures of Pt-based catalysts have been developed in our lab, such as shape/composition-controlled Pt-based nanoparticles, carbon-encapsulated Pt clusters, and Pt single-atom catalysts. The actual fuel cells should operate under various transient conditions such as H₂ starvation or oxygen cross-over across the polymer membrane, so highly durable catalysts such as reversal-tolerant anode and selective anode have been developed.

[2] Water electrolyzer

Water electrolyzer is the key technology of ‘green hydrogen’, which produces H₂ from water using electricity. Supposing that we have enough electricity from solar cells or wind power, its long-term storage or transportation over long distance can’t be achieved by battery. Particularly, because Korea does not have enough sustainable natural resources such as sunlight or wind, the technology related to carbon-neutral energy production/storage/transportation is crucial. Proton exchange membrane water electrolyzer (PEMWE) and anion exchange membrane water electrolyzer (AEMWE) are the most widely tested recently. We are developing the catalysts for PEMWE and AEMWE; the catalysts shouldn’t be tested in half-cell setup only, but be tested in membrane-assembly-electrode (MEA) level. We are minimizing Ir use for PEMWE and developing Ni-based catalyst for AEMWE.

[3] CO₂ electrolyzer

We are trying to convert gaseous CO₂ to CO, formates, C₂H₄, and bioplastics. This technique is in infant stage, but it has huge potential to produce chemicals and fuels directly from CO₂ such as photosynthesis. Whereas the natural photosynthesis suffers from low productivity and long reaction time, we are developing inorganic catalysts enabling this chemical conversion. We are developing various novel concepts of reactors such as GDE (gas-diffusion-electrode) electrolyzer, photo-assisted electrolyzer, and biohybrid system consisting of electrolyzer and fermenter.

[4] Air purification

Heterogeneous catalysts have been extensively used to purify air from various pollutants such as micro-dusts, NO_x, SO_x, etc. Methane oxidation at low temperature has also received much attention recently due to climate change issue. We are developing various heterogeneous atomic catalysts for the gas-phase reactions. Particularly, we are studying how to control atomic structure of precious metals on oxide-derived support; single-atomic catalyst, ensemble catalyst, and nanoparticle catalyst. By precisely controlling the surface atomic structure, we can elucidate the relationship between the surface structure and activity/durability.