Department of Chemistry, School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070, PR China.
Dalton Trans. 2018 May 8;47(18):6370-6377. doi: 10.1039/c8dt00780b.
Coupling crystal-facet engineering with selective interfacial modification has been demonstrated to be an effective strategy to enhance the photocatalytic performance of semiconductor photocatalysts. For instance, BiVO4 exhibited excellent photocatalytic activity when Pt cocatalyst was selectively modified on the (010) facet of BiVO4 single-crystal photocatalyst with exposed (010) and (110) facets. In view of the high cost and rarity of metallic Pt, it was desirable to discover low-cost electron cocatalysts that show comparable activity with Pt. In the study, Ag2O-Ag as a novel and highly efficient electron cocatalyst was selectively modified on the (010) facet of single-crystal BiVO4 photocatalyst via facile photodeposition of metallic Ag and its subsequent partial oxidation to Ag2O via low-temperature calcination (100-400 °C). In detail, Ag was selectively modified on the electron-rich (010) facet of BiVO4 single crystal, while Ag2O was selectively formed on the Ag surface, resulting in the formation of Ag2O-Ag/BiVO4 photocatalyst. As a result, Ag2O-Ag/BiVO4 exhibited nearly comparable activity with Pt/BiVO4, but clearly higher activity than Ag/BiVO4 or BiVO4 alone. The enhanced performance was ascribed to the synergistic effect of crystal-facet engineering of BiVO4 and selective modification of Ag2O-Ag electron cocatalyst. In detail, the single crystal structure of BiVO4 results in the orientation transport of photogenerated carriers, while metallic Ag effectively transfers photogenerated electrons of BiVO4 and then, Ag2O as the active site accelerates the reduction of dissolved oxygen. Considering that our present synthetic strategy is facile, controllable and economical, this study provides insight into the design and synthesis of highly efficient semiconductor photocatalysts.
通过耦合晶面工程和选择性界面修饰，已经证明这是一种增强半导体光催化剂光催化性能的有效策略。例如，当 Pt 共催化剂选择性修饰在具有暴露的（010）和（110）面的 BiVO4 单晶光催化剂的（010）面上时，BiVO4 表现出优异的光催化活性。鉴于金属 Pt 的高成本和稀有性，人们希望发现具有可比活性的低成本电子共催化剂。在该研究中，Ag2O-Ag 作为一种新型高效电子共催化剂，通过简单的光沉积金属 Ag 及其随后在低温煅烧（100-400°C）下部分氧化为 Ag2O，选择性修饰在单晶 BiVO4 光催化剂的（010）面上。具体来说，Ag 选择性修饰在电子富有的（010）面上，而 Ag2O 选择性形成在 Ag 表面上，从而形成 Ag2O-Ag/BiVO4 光催化剂。结果，Ag2O-Ag/BiVO4 表现出与 Pt/BiVO4 几乎相当的活性，但明显高于 Ag/BiVO4 或单独的 BiVO4。增强的性能归因于 BiVO4 的晶面工程和选择性修饰 Ag2O-Ag 电子共催化剂的协同效应。具体来说，BiVO4 的单晶结构导致光生载流子的定向输运，而金属 Ag 有效地转移 BiVO4 的光生电子，然后 Ag2O 作为活性位点加速溶解氧的还原。考虑到我们目前的合成策略简单、可控且经济，这项研究为高效半导体光催化剂的设计和合成提供了新的思路。
