Photo-induced Pt/BiVO₄/Bi₂O₃ hetero-structures for methanol oxidation

and new insights on photo/electro-catalysis coupling mechanism

Gong Wang^#, Xingming Xie^#, Xuejing Cui, Jing Liu, Luhua Jiang*

Nanomaterials and Electrocatalysis Laboratory, College of Materials Science & Engineering, Qingdao University of Science and Technology, 53 Zhengzhou Road, Qingdao 266042, Shandong, China

ABSTRACT: Methanol electro-oxidation (MOR), as the anodic reaction of direct methanol fuel cells (DMFCs), is sluggish in kinetics, which limits the fuel cell performance seriously. Coupling electrocatalysis with photocatalysis is possibly to promote the MOR kinetics, yet is challengeable due to lack of well-designed photoelectrocatalysts and poor understanding in photo-electro-catalysis coupling mechanism. Herein, a photo-induced strategy is reported to generate a Pt/BiVO₄/Bi₂O₃ hetero-structured catalyst, which displays superior photo-electro-catalytic activity for the MOR under irradiation. The in-situ generated Pt/BiVO₄/Bi₂O₃ hetero-structured catalyst is efficient for photogenerated charge separation and transfer, taking advantage of both tailored band structures and compatible interfaces. Mechanism study discovers that the kinetics of methanol dehydrogenation on Pt are promoted by the photogenerated OH_ad on BiVO₄/Bi₂O₃ heterojunctions, leading to a CO_ad poison free pathway. This work provides a new photo-induced strategy to synthesize hetero-structured catalysts, and most importantly, the identification of the MOR pathway sheds lights on the underlying photo-electro-catalysis coupling mechanism, paving an avenue for construction of high-performance DMFCs.

KEYWORDS: Photo-induced strategy; Pt/BiVO₄/Bi₂O₃ hetero-structures; methanol oxidation; photo-electro-catalysis; coupling mechanism.