Colloidal Synthesis of Ultrathin Monoclinic BiVO₄ Nanosheets for Z-Scheme Overall Water Splitting under Visible Light

Abstract

Recently, ultrathin 2D photocatalysts have attracted people’s attention due to their performances in the area of solar energy conversion. However, the synthesis of ultrathin 2D photocatalysts with a nonlayered crystal structure is still full of challenges. Herein, ultrathin 2D BiVO4 nanosheets (NSs) with monoclinic crystal structure are synthesized through a convenient colloidal two-phase method. The as-prepared BiVO4 NSs possess a thickness of less than 3 nm but a diameter larger than 1.2 μm. Furthermore, the presence of HNO3 facilitates the growth of BiVO4 NSs with nearly naked surfaces, largely exposed {010} planes, and widely distributed oxygen vacancies (V O) inside the crystalline structure, which are of great benefit to their photocatalytic activity under visible light irradiation. As a result, our ultrathin 2D BiVO4 NSs exhibit an impressive photocatalytic performance for water oxidation. The O2 evolution rate is 107.4 μmol h–1, and the apparent quantum yield (AQY) is as high as 26.1% (420 nm). Furthermore, by employing our ultrathin 2D BiVO4 NSs as the O2-evolving photocatalyst, Ru-SrTiO3:Rh and Fe3+/Fe2+ as the H2-evolving photocatalyst, and the redox mediator, respectively, a Z-scheme overall water splitting system is successfully constructed. Under visible light irradiation, our Z-scheme photocatalytic system presents high H2 and O2 evolution rates (16.7 and 8.0 μmol h–1) with an AQY of 1.88% (420 nm) and good photocatalytic stability.

Ru Nanoparticles Supported on Oxygen‐Deficient 3DOM BiVO4: High‐Performance Catalysts for the Visible‐Light‐Driven Selective Oxidation of Benzyl Alcohol

“…Similar conclusions have also been drawn by other researchers. [19,34,37] Recently, various photocatalysts have been investigated for selective photocatalytic oxidation of benzyl alcohol to benzaldehyde, [38][39][40][41][42] and their activities are listed in Table S1. It is found that the 0.95Ru/3DOM BiVO 4 À Ar-300 sample showed better photocatalytic performance than most of the reported photocatalysts (except 0.3 wt % Pt/Bi 2 MoO 6 ).…”

“…Among the Bi-based semiconductors, BiVO 4 with an environmental benignity and a high stability has attracted much attention. [18][19][20] BiVO 4 is usually used in water splitting and environmental remediation, but only few studies on the photocatalytic synthesis of fine chemicals over BiVO 4 have been seen in the literature. [4,21] Furthermore, cheaper Ru in price than Pt could be used as a promising cocatalyst since it showed high selectivity in photocatalytic oxidation of toluene and good activity in photocatalytic reduction of CO 2 .…”

Stepping towards Solar Water Splitting: Recent Progress in Bismuth Vanadate Photoanodes

“…The morphology of nanomaterials has significant impacts on the interfacial energetics, kinetics and charge transport properties . Therefore, understanding and controlling the structural aspects of BiVO 4 photoanodes can provide an effective way to enhance its PEC performance .…”

“…The morphology of nanomaterials has significant impacts on the interfacial energetics, kinetics and charge transport properties. [64][65][66][67] Therefore, understanding and controlling the structural aspects of BiVO 4 photoanodes can provide an effective way to enhance its PEC performance. [15,68] In this subsection, strategies developed to obtain desirable porosities and preferred crystal facets are reviewed.…”

Self‐templated Constructing of Heterophase Junction into Hierarchical Porous Structure of Semiconductors for Promoting Photogenerated Charge Separation

“…[5][6][7] Particularly, photogenerated charge separation is the key and bottleneck among three basic steps. To date, various adequate strategies have been explored for facilitating spatial charge separation of semiconductor-based photocatalysts like heterojunctions, [8][9][10][11][12] especially for heterophase junctions [13][14][15] have been recognized as an effective and common approach. The construction of the phase junction formed at the interface between two crystalline phases of a specific semiconductor is found to be useful in driving the spatial separation and transfer of the photogenerated electrons and holes under the function of the built-in electrical field, [16,17] which has been widely accepted to be validated in many semiconductor-based photocatalysts, such as typical TiO 2 , WO 3 , CdS, and ZnS.…”