Publications by authors named "Jinjong Kim"

Chlorine (Cl) is one of the most important commodity chemicals that has found widespread utility in chemical industry. Most Cl is currently produced via the chlorine evolution reaction (CER) at the anode of chlor-alkali electrolyzers, for which platinum group-metal (PGM)-based mixed metal oxides (MMOs) have been used for more than half a century. However, MMOs suffer from the use of expensive and scarce PGMs and face selectivity problems due to the parasitic oxygen evolution reaction.

View Article and Find Full Text PDF
Article Synopsis
  • Electrochemical production of hydrogen peroxide (HO) through a two-electron oxygen reduction reaction (2e ORR) is gaining interest for its sustainable and on-site benefits.
  • This study focuses on improving Ni-based catalysts, specifically designing atomically dispersed catalysts (Ni ADCs) to enhance HO production efficiency while addressing the low activity of traditional Ni catalysts.
  • Key findings indicate that using a coordinated precursor and controlled pyrolysis can create highly active Ni-N sites, which are crucial for achieving a record level of mass activity and selectivity in hydrogen peroxide synthesis.
View Article and Find Full Text PDF

Platinum single-atom catalysts hold promise as a new frontier in heterogeneous electrocatalysis. However, the exact chemical nature of active Pt sites is highly elusive, arousing many hypotheses to compensate for the significant discrepancies between experiments and theories. Here, we identify the stabilization of low-coordinated Pt species on carbon-based Pt single-atom catalysts, which have rarely been found as reaction intermediates of homogeneous Pt catalysts but have often been proposed as catalytic sites for Pt single-atom catalysts from theory.

View Article and Find Full Text PDF
Article Synopsis
  • Os-based catalysts exhibit great catalytic activity but face challenges due to toxic side reactions forming OsO, especially at room temperature.
  • Research shows that reducing Os nanoparticles to atomically dispersed forms significantly enhances their thermal stability and prevents undesirable oxidation.
  • The atomically dispersed Os catalyst maintains high CO oxidation activity at 400 °C over 30 hours, unlike Os nanoparticles, which lose effectiveness rapidly.
View Article and Find Full Text PDF

Rational control of the coordination environment of atomically dispersed catalysts is pivotal to achieve desirable catalytic reactivity. We report the reversible control of coordination structure in atomically dispersed electrocatalysts via ligand exchange reactions to reversibly modulate their reactivity for oxygen reduction reaction (ORR). The CO-ligated atomically dispersed Rh catalyst exhibited ca.

View Article and Find Full Text PDF

Microlens array (MLA) diffusers for light-emitting diode (LED) backlight systems have been developed. A high fill-factor photoresist mold for the MLA was fabricated using three-dimensional diffuser lithography, and the patterns were transferred to a nickel master mold for UV-curable polymer replication. The fabricated microlens had various paraboloidal profiles, and its aspect ratio was controlled from 1.

View Article and Find Full Text PDF