Systematic Approach to Designing a Highly Efficient Core-Shell Electrocatalyst for N2O Reduction

Abstract

Nitrous oxide (N2O) is a notorious greenhouse gas because of its higher global warming potential and longer lifetime than those of CO2 and CH4. Here, we present a rational design of a highly stable and active electrocatalyst that surpasses the activity of conventional Pd catalysts for N2O reduction. Theoretical calculations predicted that the catalytic activity of surface Pd atoms in an Au@Pd core-shell structure can be increased by optimizing the thickness of the Pd shell. This prediction was confirmed by the catalytic activity of an Au substrate on which Pd overlayers of different thicknesses were precisely deposited using the atomic layer deposition method. By applying these findings, we synthesized Au@Pd nanoparticles with an optimal shell thickness that exhibited excellent catalytic activity for electrochemical reduction of N2O. The catalytic activity of Au@Pd with a Tafel slope of 0.105 V/dec was much higher than that of Pd/C (0.126 V/dec). Moreover, even after 1000 cycles, the activity decreased by only 16%, whereas it decreased by 44% on the Pd/C catalyst.