(3fp) Thermochemical CO2 Conversion by Heterogeneous Catalysts with Confined Structures

My research interest lies in the field of heterogeneous catalysis for variable applications such as oxidation, hydrogenation, or reforming reactions. The research agenda focuses on not only synthesizing unique catalysts and evaluating those in the reactions, but also fundamental understanding of the reaction mechanisms through investigating from theory to dynamic changes in experiments. I have worked on the thermochemical CO₂ conversion by heterogenous catalysts with confined structures. Specifically, I developed a yolk–shell structured nickel-based catalyst for methane reforming reactions, and an indium-based catalyst combined with a SAPO-34 zeolite tandem catalyst for CO₂ hydrogenation reaction.

Confined morphology can provide unique catalytic properties with high activity, selectivity, and stability due to the confinement effect. The developed NiCe@SiO₂ multi–yolk–shell nanotube catalysts present high performance in tri-reforming of methane (TRM), and the yolk size and Ni–Ce interaction should be tuned for obtaining stable TRM performance. In addition, single-atom Pt is promoted on the NiCe@SiO₂ catalysts and tested in dry reforming of methane (DRM) at low temperature. The yolk–shell structured single-atom Pt₁NiCe@SiO₂ nanotube catalyst shows high resistance to carbon deposition due to the low adsorption strength of CO* and singly distributed Pt species on the yolks, which strengthen the Pt–Ni–Ce interaction. Lastly, the In₂O₃/YSZ combined with SAPO-34 tandem catalyst is conducted for CO₂ hydrogenation to light olefins through methanol formation. YSZ can adopt a stable cubic fluorite structure that is prone to high levels of oxygen-ion conductivity, which leads to high diffusivity of oxygen vacancies within the In₂O₃. The lattice oxygen vacancies serve as active sites for the chemisorption of CO₂, leading to produce high light olefins selectivity without deactivation during CO₂ hydrogenation reaction.

I would like to keep pursuing CO₂ conversion reactions. Many reactions that utilize CO₂ as a feedstock have been explored such as CO₂ hydrogenation, reverse water-gas shift reaction, and dry reforming of methane to reduce the amount of CO₂ in atmosphere. Among them, CO₂ hydrogenation to methanol has been particularly interesting because methanol is a valuable starting material for the synthesis of a multitude of other organic chemicals. Therefore, innovative catalysts exhibiting high activity, methanol selectivity, and stability with suppressing undesired CO production is of interest. In addition, I am interested in studying single atoms catalysts (SACs) with unique electronic and geometric structure which has been a great surge of interest in the past several years. Synthesizing SACs without thermal deactivation or sintering is very important for applying at elevated reaction temperatures. Also, bimetals with distinct chemical and electronic properties from the parent metals can be employed in chemical reactions from the cooperative interactions between the metals. The electronic and geometric effects between two bimetals can enhanced the activity and selectivity of the catalytic reactions. The singly dispersed bimetallic sites (SBMS) can facilitate the dissociation of a reactant to form intermediate or product in different process, which can enhance the catalytic activity and selectivity. The SBMS catalysts has been researched in several reactions such as NO reduction, ethanol dehydrogenation, and oxygen evolution/reduction reaction. I would like to investigate the SBMS, which utilize unique properties of both SACs and bimetal, thus fundamental study with extensive experimental data can allow us to overcome the challenge of using catalysts in both industry and academic perspectives.