在BiVO4中使用密度函数理论和XPS实验研究了氧化演化反应 (OER) 活性位点
Qingyan Zhang1, Guowei Liu1, Taifeng Liu1
1National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials, Henan University, Kaifeng 475004, China. tfliu@vip.henu.edu.cn.
Physical chemistry chemical physics : PCCP
|January 3, 2024
概括
乙瓦纳酸盐 (BiVO4) 显示较低的水氧化活性,因为其位不适合氧化演化反应. 这项研究揭示了稳定的VO4结构阻止V原子作为活性位点,与Bi位点不同.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 计算化学计算化学
背景情况:
- 乙瓦纳酸盐 (BiVO4) 是光催化水分裂的有前途的半导体,因为它很容易合成和2.4 eV的带间隙.
- 然而,BiVO4具有较低的光催化水氧化活性,氧化演化反应 (OER) 的活性位点尚不清楚.
- 目前的文献将Bi原子确定为OER活性位点,而V原子尚未对OER进行研究.
研究的目的:
- 调查BiVO4中V原子对于氧演化反应 (OER) 的作用.
- 阐明BiVO4.中低OER活动的根本原因.
- 提供关于含瓦纳光催化剂中的OER活性的基本见解.
主要方法:
- 用密度函数理论 (DFT) 的计算来研究BiVO4.4的电子结构和表面特性.
- 进行了初始分子动力学模拟,以评估不同温度下表面结构的稳定性和V原子协调.
- 使用X射线光电子光谱 (XPS) 来描述BiVO4形态的表面组成和氧化状态.
主要成果:
- DFT和分子动力学模拟显示,BiVO4中的VO4四面体结构非常稳定,即使在高温 (300-673 K) 下也是如此.
- 表面重建导致V原子保持大量的协调,任何理论上预测的不和V位随时通过从水中吸收氧气来改造VO4.
- XPS的表征证实了不和Bi位点的存在,但在BiVO4表面没有发现不和V位点的证据,支持了理论发现.
结论:
- 稳定的VO4结构及其改革倾向使BiVO4中的V位不适合OER,原因是吸附剂/中间体吸附和脱附的困难.
- 这项研究表明,V原子在BiVO4中不是OER的活性位点,与Bi位点的既定作用形成鲜明对比.
- 这些发现为增强BiVO4的OER活动和理解相关光催化材料中的OER机制提供了关键的见解.
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