Xingming Xie, Jianguang Feng, Xuejing Cui, Jing Liu*, Luhua Jiang*, Lifeng Dong

College of Materials Science & Engineering, Qingdao University of Science & Technology, Qingdao, 266042, P.R. China.

Department of Physics, Hamline University, St. Paul 55104, Unites States

KEYWORDS: photoelectrocatalysis, methanol oxidation, plasmon effect, coupling effect, mechanism

ABSTRACT:

Methanol electro-oxidation reaction (MOR), as the anode reaction of direct methanol fuel cells (DMFC), fundamentally determines the device efficiency. Coupling electrocatalysis with photocatalysis provides a promising yet challenging strategy to accelerate the MOR kinetics. Herein, we demonstrate that the localized surface plasmon resonance (LSPR) from Ag strengthens the photo-/electrocatalysis coupling process, leading to a dramatical decrease in apparent activation energy and thus doubling MOR currents over Pt/Ag_0.333V₂O₅ under illumination versus in dark. Mechanism investigations reveal that the MOR enhancement can be mainly attributed to the accelerated dehydrogenation of methanol on a negatively charged Pt surface facilitated by the photogenerated OH_ad on Ag_0.333V₂O₅, leading to a CO_ad-free dominant pathway, and the LSPR of Ag promotes the charge transfer in the coupling process. This study sheds light on the mechanism of plasmonic metals involved photo-/electrocatalysis coupling process and provides an avenue for designing highly efficient MOR photo/electrocatalysts.

https://doi.org/10.1021/acscatal.1c03756