Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, China.
Chem Soc Rev. 2014 Jul 7;43(13):4395-422. doi: 10.1039/c3cs60438a. Epub 2014 Mar 25.
Solar energy utilization is one of the most promising solutions for the energy crises. Among all the possible means to make use of solar energy, solar water splitting is remarkable since it can accomplish the conversion of solar energy into chemical energy. The produced hydrogen is clean and sustainable which could be used in various areas. For the past decades, numerous efforts have been put into this research area with many important achievements. Improving the overall efficiency and stability of semiconductor photocatalysts are the research focuses for the solar water splitting. Tantalum-based semiconductors, including tantalum oxide, tantalate and tantalum (oxy)nitride, are among the most important photocatalysts. Tantalum oxide has the band gap energy that is suitable for the overall solar water splitting. The more negative conduction band minimum of tantalum oxide provides photogenerated electrons with higher potential for the hydrogen generation reaction. Tantalates, with tunable compositions, show high activities owning to their layered perovskite structure. (Oxy)nitrides, especially TaON and Ta3N5, have small band gaps to respond to visible-light, whereas they can still realize overall solar water splitting with the proper positions of conduction band minimum and valence band maximum. This review describes recent progress regarding the improvement of photocatalytic activities of tantalum-based semiconductors. Basic concepts and principles of solar water splitting will be discussed in the introduction section, followed by the three main categories regarding to the different types of tantalum-based semiconductors. In each category, synthetic methodologies, influencing factors on the photocatalytic activities, strategies to enhance the efficiencies of photocatalysts and morphology control of tantalum-based materials will be discussed in detail. Future directions to further explore the research area of tantalum-based semiconductors for solar water splitting are also discussed.
太阳能利用是解决能源危机最有前途的方法之一。在所有可能利用太阳能的方法中，太阳能分解水是引人注目的，因为它可以将太阳能转化为化学能。所产生的氢气清洁且可持续，可用于各种领域。在过去的几十年中，人们在这个研究领域投入了大量的努力，取得了许多重要的成果。提高半导体光催化剂的整体效率和稳定性是太阳能分解水的研究重点。基于钽的半导体，包括氧化钽、钽酸盐和钽（氧）氮化物，是最重要的光催化剂之一。氧化钽的带隙能量适合于整体太阳能分解水。氧化钽更负的导带最小值为光生电子提供了更高的生成氢气反应潜能。具有可调组成的钽酸盐由于其层状钙钛矿结构表现出高活性。（氧）氮化物，特别是 TaON 和 Ta3N5，具有较小的带隙以响应可见光，但它们仍可以通过适当的导带最小值和价带最大值位置实现整体太阳能分解水。本综述描述了提高基于钽的半导体光催化活性的最新进展。在引言部分将讨论太阳能分解水的基本概念和原理，然后讨论基于三种主要类型的钽基半导体。在每一类中，将详细讨论合成方法、对光催化活性的影响因素、提高光催化剂效率的策略以及基于钽的材料的形态控制。还讨论了进一步探索基于钽的半导体在太阳能分解水领域的研究方向。
