Liu Siyuan, Pan Jian, Kong Weiyu, Li Xin, Zhang Jianyu, Zhang Xiaoxiao, Liu Runlu, Li Yao, Zhao Yixin, Wang Dawei, Zhang Jianqin, Zhu Shenmin
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Particles and Catalysis Research Group, School of Chemical Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia.
ACS Appl Mater Interfaces. 2022 Mar 16;14(10):12180-12192. doi: 10.1021/acsami.1c22250. Epub 2022 Mar 2.
Water oxidation process is a pivotal step of photosynthesis and stimulates the progress of high-performance catalysts for renewable fuel production. Despite the performance benefit of cocatalysts, defect engineering holds promise to settle inherent limitations of semiconductors aiming at sluggish water oxidation. Here, we modify the growth pathway of monoclinic BiVO (m-BiVO) on reduced graphene oxide (rGO), constructing abundant surface oxygen vacancies (O)-incorporated m-BiVO/rGO heterostructure toward water oxidation reaction under visible light. Owing to the O in the m-BiVO component, a vacancy-related defect level allows more electrons to be photoexcited by low-energy photons to cause the electron transition, boosting photoabsorption as well as photoexcitation. Besides, the O can reinforce surface adsorption and reduce the dissociation energy of water molecules. Particularly because of the synergy of O and cocatalyst rGO, the O functions as electron-trapped sites to facilitate the carrier separation; the rGO not only receives electrons from m-BiVO promoted by internal electric field over Mott-Schottky heterostructures but also spurs further electron diffusion along a highly conductive carbon network. These merits enable the O-incorporated m-BiVO/rGO heterostructure with an over 209% growth in O yield relative to the counterpart. The increased performance is also validated by the significant rise of OH radicals and O radicals. The current work paves a novel avenue for the integration of defect engineering and cocatalyst coupling in artificial photosynthesis.
水氧化过程是光合作用的关键步骤，对促进用于可再生燃料生产的高性能催化剂的发展具有重要意义。尽管助催化剂具有性能优势，但缺陷工程有望解决半导体在水氧化反应中存在的固有局限性，因为水氧化反应较为缓慢。在此，我们改变了单斜相BiVO（m-BiVO）在还原氧化石墨烯（rGO）上的生长路径，构建了富含表面氧空位（O）的m-BiVO/rGO异质结构，以用于可见光下的水氧化反应。由于m-BiVO组分中的O，与空位相关的缺陷能级使得更多电子能够被低能光子光激发，从而引发电子跃迁，增强了光吸收以及光激发。此外，O能够增强表面吸附并降低水分子的离解能。特别值得一提的是，由于O与助催化剂rGO的协同作用，O起到电子捕获位点的作用，促进了载流子的分离；rGO不仅通过Mott-Schottky异质结构上的内电场接收来自m-BiVO的电子，还沿着高导电碳网络促进了进一步的电子扩散。这些优点使得含O的m-BiVO/rGO异质结构相对于对照物的O产率增长超过209%。OH自由基和O自由基的显著增加也验证了性能的提升。当前的工作为人工光合作用中缺陷工程与助催化剂耦合的整合开辟了一条新途径。
