Li Xue Wei, Chen Guangri, Zhu Guoliang, Shan Lianwei, Suriyaprakash Jagadeesh, Wu Haitao, Li Xuejiao, He Xiulan, Dong Limin, Shi Ziqi
Heilongjiang Provincial Key Laboratory of CO2 Resource Utilization and Energy Catalytic Materials, School of Materials Science and Chemical Engineering, Harbin University of Science and Technology, Harbin 150040, China.
Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China.
Langmuir. 2025 Sep 9;41(35):23788-23804. doi: 10.1021/acs.langmuir.5c03072. Epub 2025 Aug 28.
The most cost-effective and environmentally benign method of producing hydrogen fuel from water is solar-driven hydrogen production, using efficient photocatalysts with low-energy photons. Engineering such a photocatalyst remains highly challenging. In this work, BiOBr(001) and BiOBr(010) nanosheets were synthesized using the hydrothermal method. Oxygen vacancies (OVs) were engineered in the BiOBr(001) and BiOBr(010) nanosheets by using a UV light-driven strategy. BiOBr(001) with OVs outperforms BiOBr(010) with OVs in photocatalytic activity for hydrogen evolution, producing 219.33 μmol·g within 4 h. So far, this is the highest photocatalytic hydrogen evolution performance of bismuth-based photocatalysts without cocatalysts. The electrochemical study results indicate that OVs considerably lower the overpotential of the hydrogen evolution reaction (HER). Experimental results show that OVs can enhance the reduction ability of photogenerated electrons and extend the lifetime of carriers. Their presence significantly enhances charge carrier separation by breaking the local structural symmetry, as demonstrated by density functional theory. Additionally, phenol hydroxylation is greatly enhanced due to the strong HO decomposition ability of BiOBr(001) with OVs. OVs increase the carrier concentration of the (010) crystal facet, while theoretical calculations reveal that OVs greatly suppress the carrier recombination probability on the (001) crystal facet. Here, we propose that the "hydroxyl blocking effect" on the (001) crystal facet of BiOBr is responsible for the low HER and phenol hydroxylation activities. By optimizing hydroxyl adsorption free energy via OVs, the conversion rate of phenol hydroxylation over the (001) crystal facet with OVs can be achieved at 99.2%. This work offers the fundamental understanding required to improve the photocatalytic efficiency of BiOBr and related photocatalysts by introducing oxygen vacancies (OVs) and altering the crystal facets.
从水中生产氢燃料最具成本效益且对环境无害的方法是利用高效光催化剂和低能光子进行太阳能驱动制氢。设计这样一种光催化剂仍然极具挑战性。在这项工作中，采用水热法合成了BiOBr(001)和BiOBr(010)纳米片。通过紫外光驱动策略在BiOBr(001)和BiOBr(010)纳米片中引入氧空位（OVs）。具有氧空位的BiOBr(001)在光催化析氢活性方面优于具有氧空位的BiOBr(010)，在4小时内产生219.33 μmol·g。到目前为止，这是无助催化剂的铋基光催化剂最高的光催化析氢性能。电化学研究结果表明，氧空位显著降低了析氢反应（HER）的过电位。实验结果表明，氧空位可以增强光生电子的还原能力并延长载流子寿命。如密度泛函理论所示，它们的存在通过打破局部结构对称性显著增强了电荷载流子分离。此外，由于具有氧空位的BiOBr(001)具有很强的HO分解能力，苯酚羟基化作用大大增强。氧空位增加了(010)晶面的载流子浓度，而理论计算表明，氧空位大大抑制了(001)晶面上的载流子复合概率。在此，我们提出BiOBr(001)晶面上的“羟基阻断效应”是导致低析氢反应和苯酚羟基化活性的原因。通过氧空位优化羟基吸附自由能，具有氧空位的(001)晶面上苯酚羟基化的转化率可达99.2%。这项工作为通过引入氧空位（OVs）和改变晶面来提高BiOBr及相关光催化剂的光催化效率提供了所需的基本认识。
