Phase Segregated Pt-SnO2 /C Nanohybrids for Highly Efficient Oxygen Reduction Electrocatalysis.

Strengthening the interfacial interaction in heterogeneous catalysts can lead to a dramatic improvement in their performance and allow the use of smaller amounts of active noble metal, thus decreasing the cost without compromising their activity. In this work, a facile phase-segregation method is demonstrated for synthesizing platinum-tin oxide hybrids supported on carbon black (PtSnO2 /C) in situ by air annealing PtSn alloy nanoparticles on carbon black. Compared with a control sample formed by preloading SnO2 on carbon support followed by deposition of Pt nanoparticles, the phase-segregation-derived PtSnO2 /C exhibits a more strongly coupled PtSnO2 interface with lattice overlap of Pt (111) and SnO2 (200), along with enhanced electron transfer from SnO2 to Pt. Furthermore, the PtSnO2 active sites show a strong ability to degrade reactive oxygen species. As a result, the PtSnO2 /C nanohybrids exhibit both excellent activity and stability as a catalyst for the oxygen reduction reaction, with an overall performance which is superior to both the control sample and commercial Pt/C catalyst. This phase-segregation method can be expected to be applicable in the preparation of other strongly coupled nanohybrids and offers a new route to high-performance heterogeneous catalysts for low-cost energy conversion devices.