Ultrasound assisted deposition of highly stable self-assembled Bi2MoO6 nanoplates with selective crystal facet engineering as photoanode

• Published in: Ultrasonics sonochemistry 2020-10, Vol.67, p.105145-105145, Article 105145
• Main Authors: Zargazi, Mahboobeh, Entezari, Mohammad H.
• Format: Article
• Language: English
• Subjects: Bismuth molybdate; Coral-like; Crystal facet engineering; Self-assembled nanoplates; Sonoelectrodeposition; Water splitting
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2020.105145

This figure presents the preparation of two different morphologies of BMO film by ED and SED methods. The stability of films represents by current-time curve which suggested BMO (SED) has higher applicable potential for PEC water splitting than BMO (ED). [Display omitted] •Crystal facet engineering occurred by sonoelectrodeposition method.•New morphologies form by electrodeposition and sonoelectrodeposition.•High photocurrent almost 1 mAcm−2 achieved by self-assembled nanoplates.•PEC water splitting with ABPE 0.31% obtained at 0.0 V vs Ag/AgCl. The use of crystal facets of photocatalysts is well known as a promising strategy for the design of new photocatalysts with interesting physicochemical features for energy production applications. In this work, Bi2MoO6 thin films were synthesized by two methods, electrodeposition and sonoelectrodeposition. Preferential growth orientation depended on synthesis method. Results suggested that sonoelectrodeposition led to dominate the crystal facet {1 0 0} growth with self-assembled nanoplate morphologies while growth orientation in the {0 1 0} facet was dominant in electrodeposition in the absence of ultrasonic waves. As a highlight result, the {1 0 0} facet shows a smaller band gap, higher photocatalytic water splitting than the {0 1 0} facet. Efficient separation of charge pairs and long life time of photogenerated electrons was observed to be intrinsic features of the {1 0 0} facets. The higher charge transfer was confirmed by a higher photocurrent from linear sweep voltammetry and a smaller Nyquist radius arc. Ultrasound plays a key role in growth orientation and led to a production of homogeneous films with nanoplates which self-assembled together to form a flower-like structure. While in the absence of ultrasound the film has coral-like structure. Highly stable sonoelectrodeposited films exhibited incident photon-to-electron conversion efficiency (IPCE) of 22.4% at the specific wavelength of 500 nm. The sonoelectrodeposition method could act as a promising method for forming new films with specific crystal facet selection and developing as highly efficient photoanodes for PEC water splitting.