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Novel photocatalytic water splitting solar-to-hydrogen energy conversion: CdLa2S4 and CdLa2Se4 ternary semiconductor compounds
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2018-02-19 00:00:00 , DOI: 10.1039/c8cp00373d
A. H. Reshak 1, 2, 3, 4
Affiliation  

Comprehensive ab initio calculations from first- to second-principles methods are performed to investigate the suitability of non-centro-symmetric CdLa2S4 and CdLa2Se4 to be used as active photocatalysts under visible light illumination. The calculations reveal the direct band gap nature of both compounds with large absorption coefficients (104–105 cm−1). The absorption edges of CdLa2S4 and CdLa2Se4 occur at λ = 579.3 nm and λ = 670.1 nm, and the optical band gaps are estimated to be 2.14 eV and 1.85 eV for CdLa2S4 and CdLa2Se4, respectively. These gaps are larger than 1.23 eV the required optical band gap for photocatalytic performance to split water under visible light illumination. The calculated potentials of the conduction band and the valence band edges indicate that CdLa2S4 and CdLa2Se4 have strong reducing powers for H2 production. The obtained results reveal that the high photogenerated carrier mobility favors enhancement of the photocatalytic performance. It has been found that there is a large mobility difference between the electrons (e) and the holes (h+), which is useful for the separation of e and h+, reduction of e and h+ recombination rate, and improvement of the photocatalytic activity. Based on these findings, one can conclude that CdLa2S4 and CdLa2Se4 satisfied all requirements to be efficient photocatalysts. This will greatly improve the search efficiency and greatly help experiments to save resources in the exploration of new photocatalysts with good photocatalytic performances.

中文翻译:

新型光催化水分解太阳能转化为氢:CdLa 2 S 4和CdLa 2 Se 4三元半导体化合物

进行了从第一至第二原理的全面从头计算,以研究非中心对称的CdLa 2 S 4和CdLa 2 Se 4在可见光照射下用作活性光催化剂的适用性。计算结果表明两种化合物的直接带隙性质都具有较大的吸收系数(10 4 –10 5 cm -1)。CdLa 2 S 4和CdLa 2 Se 4的吸收边缘出现在λ = 579.3 nm和λ= 670.1nm,并且对于CdLa 2 S 4和CdLa 2 Se 4,光学带隙估计分别为2.14eV和1.85eV 。这些间隙大于光催化性能在可见光照射下将水分解所需的光学带隙1.23 eV。计算出的导带和价带边缘的电势表明,CdLa 2 S 4和CdLa 2 Se 4对H 2具有很强的还原能力生产。获得的结果表明,高的光生载流子迁移率有利于增强光催化性能。已经发现,存在电子(e之间大的迁移率的差异- )和空穴(h +),这是为电子的分离有用-和H +,减少电子商务-和h +重组率,和改善光催化活性。根据这些发现,可以得出CdLa 2 S 4和CdLa 2 Se 4的结论。满足了成为高效光催化剂的所有要求。这将大大提高搜索效率,并极大地帮助实验节省了探索具有良好光催化性能的新型光催化剂的资源。
更新日期:2018-02-19
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