Assist more Pt-O bonds of Pt/MoO3-CNT as a highly efficient and stable electrocatalyst for methanol oxidation and oxygen reduction reaction

Abstract

Pt-based catalysts are widely used in polymer electrolyte fuel cells. However, it still exists tremendous challenge on improving the activity and durability of electrocatalysts. Herein, Pt nanoparticles (NPs) are supported on the dispersed MoO3-modified carbon nanotubes (CNTs) via an atomic layer deposition (ALD) technology. In the resulting Pt-MoO3/CNT-ALD, Pt NPs are selectively anchored on the interface of MoO3 and CNTs to increase the Pt-O bonds and strengthen the metal-metal oxide interaction (MMOI). The regulated electronic structure of Pt can remarkably enhance the intrinsic catalytic activity. For methanol oxidation reaction, Pt-MoO3/CNT-ALD exhibits high activity with a mass activity of 1221.1 mA·mgPt−1 at 0.9 V which represents a 4.2-fold improvement over the corresponding activities of commercial Pt/C. And for oxygen reduction reaction, it shows the onset potential and half potential of 1.04 V and 0.87 V, respectively. Most importantly, Pt-MoO3/CNT-ALD exhibits excellent long-term stability without distinct degradation (98.9% retention of electrochemical surface area and 92.4% retention of mass activity) after 10,000 cycles. In single cell test, the maximum power density and durability of the Pt-MoO3/CNT-ALD is achieved to be 589 mW·cm−2 and 94.8% retention after 3000 cycles. The Pt-MoO3/CNT-ALD with high activity and durability is attributed to the increased Pt-O bonds, optimized electronic structure and strengthened MMOI. A strategy in this work is approved to facilitate the development of high-performance Pt-based electrocatalysts.