Solar Fuels

I mainly develop efficient transition metal-based oxygen evolution catalysts via electrochemical synthesis for energy conversion applications. My research focus is tailoring transition metal-based electrocatalysts on photoanodes and investigating not only their electrocatalytic activity but also photoelectrochemical behavior.

Through the heterojunction with various photoelectrode materials, we improve the light absorption, charge separation, and charge injection efficiencies for solar water oxidation. Photoelectrochemical performances are further maximized by nanostructuring the photoelectrodes through the dimension control of materials based on the solution process. Based on these synergistic effects of heterostructures and nanostructures, we fabricate tandem systems with solar cells or other photoelectrodes to spontaneously produce solar hydrogen without external bias.

We synthesized various multi-component metal alloys as a new electrocatalysts candidate and optimize the catalytic properties for efficient water electrolysis. Connecting these electrocatalysts with a photovoltaic device, we produce the hydrogen without the external voltage.

Although the research on energy conversion devices has been conducted for a long time, we are still facing several problems such as low efficiency and poor stability. To overcome the encountered problems and improve the device performance, it is essential to understand the fundamentals of the device. To comprehend the basics of the devices, we studied the atomically controlled epitaxial heterostructure using various engineering techniques such as epitaxial strain, doping, and so on.

We develop highly active, stable, and low-cost photoelectrochemical (PEC) hydrogen evolution reaction (HER) catalysts based on nanostructured transition metal disulfides (TMDs) and transition metal phosphides (TMPs) such as MoS₂, WS₂, VS₂, NbS₂, MoP, and CoP.