Liu Siyuan, Pan Jian, Li Xin, Meng Xin, Yuan Hao, Li Yao, Zhao Yixin, Wang Dawei, Ma Jun, Zhu Shenmin, Kong Lingti
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Nanoscale. 2020 Jul 21;12(27):14853-14862. doi: 10.1039/d0nr02718a. Epub 2020 Jul 7.
Owing to the sluggish water oxidation process, unearthing an ideal model for disclosing the impact of an architectural approach on the water oxidation activity of photocatalysts becomes a vital issue. Here, we propose an innovative in situ modification strategy for constructing ultrapure BiVO nanosheets on graphene (u-BVG) toward the accelerated photocatalytic water oxidation reaction. Considering the Mott-Schottky heterojunctions at the contact interface in u-BVG, the feasible electron transfer from excited BiVO to graphene facilitates the holes to migrate onto the BiVO surface for the water oxidation reaction. Compared with the conventional synthesis strategies, our strategy avoids the introduction of Cl impurities. This modification allows for not only a ca. 0.1 eV deeper valence band edge position to generate holes with a stronger oxidation potential but the extraction of the impurity level to suppress the carrier recombination. And density functional theory calculations are in accordance with the above results. Impressively, these merits endow the u-BVG with ca. 16.8 times growth in the amount of ˙OH radicals derived from OH/HO oxidation, an over 260% enhancement in O yield and a 1.6-fold increase in the apparent quantum efficiency relative to the impure counterpart. This work paves the way for the reconstruction of graphene-based binary systems with high performance in solar-to-chemical energy conversion.
由于水氧化过程缓慢，发掘一个理想模型以揭示结构方法对光催化剂水氧化活性的影响成为一个关键问题。在此，我们提出一种创新的原位修饰策略，用于在石墨烯上构建超纯BiVO纳米片（u-BVG）以加速光催化水氧化反应。考虑到u-BVG中接触界面处的莫特-肖特基异质结，从激发的BiVO到石墨烯的可行电子转移促进空穴迁移到BiVO表面进行水氧化反应。与传统合成策略相比，我们的策略避免了Cl杂质的引入。这种修饰不仅使价带边缘位置深约0.1 eV以产生具有更强氧化电位的空穴，还能去除杂质能级以抑制载流子复合。密度泛函理论计算与上述结果一致。令人印象深刻的是，这些优点使u-BVG相对于不纯的对应物，源自OH/HO氧化的˙OH自由基量增长约16.8倍，O产量提高超过260%，表观量子效率提高1.6倍。这项工作为在太阳能到化学能转换方面具有高性能的基于石墨烯的二元体系的重构铺平了道路。
