The Choi research group studies electrodes and catalysts for use in photoelectrochemical and electrochemical applications. Earlier work in the group has included the crystallization of cuprous oxide in various morphologies, in which the authors utilized electrochemistry to control the crystallization process and resultant crystal morphologies.
The Choi group has extensively studied bismuth vanadate, a photoanode for light-driven water splitting. This material suffers from facile bulk electron-hole recombination, but by combining the bismuth vanadate catalyst with oxygen-evolution catalysts such as FeOOH and NiOOH, Choi and coworkers were able to minimize this deleterious process and achieve higher catalytic efficiencies. The Choi group has also studied the stability of the bismuth vanadate catalyst, as well as the effects of surface composition on the interfacial energetics of photoelectrochemical catalysis.
In one report, Choi and coworkers developed a photoelectrochemical cell (PEC), a device that can split water into hydrogen and oxygen given inputs of light and electricity. PECs are promising devices for hydrogen production, for use in a hydrogen economy. However, the anodic reaction, the oxygen evolution reaction (OER), is slow and limits the overall process. To sidestep this problem, Choi and coworkers paired the hydrogen evolution reaction (HER) with oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). This allows them to generate FDCA, a valuable commodity chemical used in plastic production, from HMF, which can be derived from cellulose.