2025년 2학기 건국대-세종대 화학과 세미나

Synergistic Role of Interstitial B and Alloying Elements in Tailoring Pd-Based Nanocatalysts

연사: 한국에너지공과대학교 홍종욱 교수 (분석화학)

일시: 10월30일 (목) 오후 5시

장소: 건국대학교 과학관 201호

Recent advancements in interstitial alloy nanostructures have highlighted the promising role of nonmetal incorporation in tuning the electronic structures and catalytic properties of Pd-based nanocrystals (NCs). In this study, we present two complementary strategies that synergistically enhance catalytic performance in distinct electrochemical reactions by engineering the composition, crystal phase, and interstitial atom incorporation.

First, we introduce a novel ternary Pd4Bi–B interstitial alloy NC system synthesized via a sequential chemical route, where Bi promotes C–C bond cleavage and B modulates the electronic structure by shifting the d-band center downward. This dual function significantly boosts the ethanol oxidation reaction (EOR) via the C1-pathway, as evidenced by a 4.0-fold increase in mass activity compared to commercial Pd/C. Furthermore, the Pd4Bi–B NCs exhibit remarkable resistance to poisoning intermediates, enhanced OH adsorption, and outstanding electrochemical durability, demonstrating their potential as efficient anode catalysts for direct ethanol fuel cells.

In parallel, we report the crystal-phase- and B-content-dependent behavior of Pd–B interstitial alloy NCs toward the oxygen reduction reaction (ORR). Controlled synthesis enabled the transformation of fcc to hcp crystal phases with increasing B incorporation. Among these, the hcp PdB0.5 NCs exhibited superior catalytic activity with a mass activity of 2.58 A mg-1—over 10 times higher than Pd/C—attributed to the optimized d-band center and robust Pd–B bonding. The hcp phase also conferred outstanding durability under accelerated conditions.

Together, these findings elucidate the pivotal role of interstitial nonmetal doping and phase engineering in enhancing catalytic performance. This work paves the way for the rational design of multifunctional alloy nanocatalysts tailored for diverse electrochemical energy conversion applications.