Photoreactivity and Mechanism of g-C₃N₄ and Ag Co-Modified Bi₂WO₆ Microsphere under Visible Light Irradiation

Abstract

In this study, C3N4@Ag-Bi2WO6 with flower-like architecture was successfully prepared through a facile process. The C3N4@Ag-Bi2WO6 particles with 2–4 μm diameters present remarkable enhanced visible light absorption and electron–hole separation efficiency. Compared with Bi2WO6, Ag-Bi2WO6, and C3N4@Bi2WO6 systems, the C3N4@Ag-Bi2WO6 system exhibits optimal photocatalytic activities in both the degradation of RhB and hydrogen production out of water under visible light irradiation. We propose that these results are attributed to the synergy effects of Ag, g-C3N4, and Bi2WO6 nanophase structures in the C3N4@Ag-Bi2WO6 composites, which results in a fast electron–hole separation and slow charge recombination by a Z-scheme mechanism and ultimately in a higher photocatalytic activity.

Defective Bi2WO6‐Supported Cu Nanoparticles as Efficient and Stable Photoelectrocatalytic for Water Splitting in Near‐Neutral Media

“…As illustrated in Figure c, in the ternary system, CuO and Cu both act as sensitizers and cocatalysts for Bi 2 WO 6 , when it was illuminated under visible light, the electrons and holes on the Bi 2 WO 6 would transfer into the CB and VB of CuO, respectively ,. Which attribute to the special band position of CuO and Bi 2 WO 6 .…”

“…Thus, the photogenerated electrons in the CB of Bi 2 WO 6 would shift to metallic Cu and recombine with the photogenerated hole from CuO . In this manner, Cu nanoparticles might serve as a charge transport center to form the CuO@Cu‐Bi 2 WO 6 Z‐scheme system . However, the VB band edge of CuO was 0.93 eV, demonstrating without ability to reduce ⋅OH into O 2 .…”

The Bi/Bi2WO6 heterojunction with stable interface contact and enhanced visible‐light photocatalytic activity for phenol and Cr(VI) removal

“…As displayed in Fig. (a), the smaller semicircle of the binary hybrid photocatalyst reveals faster electron transfer, and the semicircular Nyquist plot also indicates that the surface electron transfer process is the rate‐determining step of reaction . Moreover, the equivalent electrical circuit [inset of Fig.…”

Au Nanoparticles (NPs) Surface Plasmon Resonance Enhanced Photocatalytic Activities of Au/Bi2WO6 Heterogeneous Nanostructures

“…, 如引入本征缺陷和掺杂 [5] , 采用微结构调控机制制 备高结晶度、 大比表面积、 高活性面暴露的 Bi 2 WO 6 (纳 米粒子 [6] 、一维 [7] 、二维 [8][9] 和三维 [10][11] ), 采用贵金 属表面修饰 [12][13] 和构筑异质结 [14][15][16][17] 等策略, 抑制载 流子的复合, 并提高量子效率, 从而改善 Bi 2 WO 6 基 催化材料的性能。 贵金属纳米粒子(NPs)的表面等离子共振效应 成为提高光催化效率的新途径 [18][19] , 由于贵金属纳 米粒子(Ag, Pt, Au)具有很强的可见光吸收能力, 能 够与半导体复合形成表面等离子体光催化材料。因 此, 将贵金属纳米粒子与半导体结合形成异质结构 成为广泛使用的光催化材料改性策略 [20][21][22][23][24][25][26][27][28] 。例如, 人们采用 AuNPs 修饰 TiO 2 [20][21] 、ZnO [22] 、CdS [23] 、 BiVO 4 [24] ; 采用 AgNPs 修饰 TiO 2 [25] 、 Bi 2 WO 6 [26] , 采 用 Pt NPs 修饰 Bi 2 WO 6 [27] 和 TiO 2 [28] 等。 文献报道, 利用 Ag 和 Pt 纳米粒子进行表面修 饰, 可显著提高 Bi 2 WO 6 的光催化活性 [26][27] 。近期, AuNPs 作为半导体表面敏化剂的研究引起人们的广 泛关注 [29][30] 自由基 [17] , 这与活性物种捕获实验结果一致。 当 Au 纳米粒子沉积在 Bi 2 WO 6 表面时, 一方面, Au 纳米粒子可以作为电子的"贮存器", 抑制光生电 子和空穴对的复合, 从而提高 Bi 2 WO 6 表面载流子的 分离效率。由于 Au 的费米能级低于 Bi 2 WO 6 的导带 边缘 [31]…”