Ex-Solution Hybrids Functionalized on Oxide Nanofibers for Highly Active and Durable Catalytic Materials

Abstract

Ex-solution catalysts containing spontaneously formed metal nanoparticles socketed on the surface of reservoir oxides have recently been employed in various research fields including catalysis and sensing, due to the process efficiency and outstanding chemical/thermal stability. However, since the exsolution process accompanies harsh reduction heat treatment, during which many oxides undergo phase decomposition, it restricts material selection and further advancement. Herein, we propose an elaborate design principle to uniformly functionalize exsolution catalysts at porous oxide frameworks via an electrospinning process. As a case study, we selected the ex-solved La0.6Ca0.4Fe0.95Co0.05‑xNixO3−δ (x = 0, 0.025 and 0.05) and SnO2 nanofibers as ex-solution hybrids and main frameworks, respectively. We confirmed superior dimethyl sulfide (C2H6S) gas sensing characteristics with excellent long-cycling stability. In particular, the high catalytic activities of ex-solved CoNiFe ternary nanoparticles, strongly socketed on reservoir oxide, accelerate the spillover process of O2 to dramatically enhance the response toward sulfuric analytes with exceptional tolerance. Altogether, our contribution represents an important steppingstone to a rational design of ex-solved particle-reservoir oxide hybrids functionalized on porous oxide scaffolds for a variety of applications.