Z型g-C3N4/WO3·H2O的制备与光催化二氧化碳还原性能

Preparation and photocatalytic carbon dioxide reduction performance of Z-scheme g-C3N4/WO3·H2O

摘要:

利用可见光将CO₂转化为CO和CH₄有望同时解决温室效应和能源危机。Z型光催化体系能够最大限度降低光生电子-空穴对的复合,提高光催化效率。本文采用水热合成法制备了g-C₃N₄/WO₃·H₂O (CNW-1)复合材料,通过X射线衍射、X射线光电子能谱、电镜等方法进行结构表征,探究了298 K、0.1 MPa条件下其对CO₂的可见光催化还原性能,并提出了可能的反应机理。通过调控三氧化钨结晶水含量可以实现CO和CH₄的产量调节,在反应10 h后,CNW-1具有最高的CH₄产率(0.33 μmolg^_-1),而CNW具有最高的CO产率(0.67 μmolg_-1⁾。这项研究为CO₂选择性还原为C1化合物提供了一种有效策略,同时也突出了以g-C₃N₄作为半导体构建Z型光催化体系在催化领域的应用潜力。

Abstract:

Using visible light to convert CO₂ into CO and CH₄ is expected to solve the greenhouse effect and energy crisis at the same time. Z-scheme photocatalytic system has attracted widespread attention because it can minimize the recombination of photo generated electron-hole pairs and improve photocatalytic efficiency. In this work, g-C₃N₄/WO₃·H₂O (CNW-1) composite material was synthesized using hydrothermal method. The structure of catalysts was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, electron microscopy, etc.. The visible photocatalytic CO₂ reduction performance of CNW-1 under 298 K and 0.1 MPa conditions was investigated, and a possible reaction mechanism was proposed. The different yield of CO and CH₄ can be obtained by adjusting the content of water of crystallization in tungsten trioxide. After 10 h of reaction, CNW-1 has the highest yield of CH₄ (0.33 μmolg_-1^{), while} g-C₃N₄/WO₃ (CNW) has the highest CO yield (0.67 μmolg_-1⁾. This study not only provides an effective strategy for the selective reduction of CO₂ to C1 compounds, but also highlights the potential application of g-C₃N₄ by construct Z-scheme photocatalytic systems for field of catalysis.