Byungchan Han
Yonsei University, Korea
Title: Design of active and durable catalysts with non-precious materials for oxygen reduction and evolution reactions: First principles prediction and experimental validation
Biography
Biography: Byungchan Han
Abstract
Using first-principles density functional theory (DFT) calculations and experimental materialization, we design highly active and durable catalysts toward oxygen reduction reaction (ORR) with nonprecious Cu@N-C materials. DFT calculations indicate that encapsulated Cu metal by N-doped carbon shells is a promising electrocatalyst for ORR. To validate the prediction we synthesize three different types of catalysts with various applied processes: (i) hydrothermally treated “Cu@N-C(hydro)”, (ii) “Cu@N-C(heat)” heat-treated at T = 1000 °C for 2 h, and (iii) “Cu@N-C(CO2)” oxidized by CO2 for 15 min at T = 1000 °C. It is shown that applying the CO2 treatment can be a key process controlling electronic structures and shell thickness of the materials leading the high ORR catalytic performance. To alleviate the substantial overpotential problem in water splitting process storing the energy in fuels of O2 and H2 we develop hexagonal perovskite oxide with a transition metal of mixed oxidation states. Both computational prediction and experimental measurements consistently show that its performance is better than IrO2.
