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First-Principles Study on ZnV 2 O 6 and Zn 2 V 2 O 7 : Two New Photoanode Candidates for Photoelectrochemical Water Oxidation
Ceramics International ( IF 5.1 ) Pub Date : 2018-04-01 , DOI: 10.1016/j.ceramint.2018.01.064
H. Sameie , A.A. Sabbagh Alvani , N. Naseri , S. Du , F. Rosei

Abstract We used first principles calculations based on density functional theory with generalized gradient approximation to investigate and compare the structural, electronic and optical properties of two photoanode materials, ZnV2O6 and Zn2V2O7, for use in photocatalytic water splitting. After geometry optimization, the calculated structural parameters evince a satisfactory agreement with the reported experimental results indicating that the used method and conditions are suitable. The electronic structures demonstrate that both photocatalysts possess favorable band gaps (2.31 and 2.52 eV) and appropriate band edge positions for oxygen evolution reaction under solar radiation. The relatively light effective masses at the valence band maximum and conduction band minimum are expected to result in enhanced photocatalytic activity due to lower recombination probability of the photogenerated electrons and holes. The analysis of electronic density of states reveal that the higher coordination number of vanadium in ZnV2O6 with respect to Zn2V2O7 causes more delocalisation of bands owning to lower V-V and O-O distances in conduction and valence bands, respectively. Moreover, the origins of features that appear in solar energy harvesting characteristics (dielectric function and optical absorption coefficient) have been discussed for solar water splitting in detail.

中文翻译:

ZnV 2 O 6 和Zn 2 V 2 O 7 的第一性原理研究:用于光电化学水氧化的两种新光阳极候选物

摘要 我们使用基于密度泛函理论和广义梯度近似的第一性原理计算来研究和比较两种用于光催化水分解的光阳极材料 ZnV2O6 和 Zn2V2O7 的结构、电子和光学性质。经过几何优化,计算的结构参数与报告的实验结果显示出令人满意的一致性,表明所使用的方法和条件是合适的。电子结构表明,两种光催化剂都具有有利的带隙(2.31 和 2.52 eV)和适合太阳辐射下析氧反应的带边位置。由于光生电子和空穴的复合概率较低,在价带最大值和导带最小值处相对较轻的有效质量有望提高光催化活性。电子态密度分析表明,相对于 Zn2V2O7,ZnV2O6 中钒的配位数越高,由于导带和价带中的 VV 和 OO 距离分别越低,导致带离域越多。此外,已经详细讨论了太阳能收集特性(介电函数和光吸收系数)中出现的特征的起源,用于太阳能水分解。电子态密度分析表明,相对于 Zn2V2O7,ZnV2O6 中钒的配位数越高,由于导带和价带中的 VV 和 OO 距离分别较低,导致带离域更多。此外,已经详细讨论了太阳能收集特性(介电函数和光吸收系数)中出现的特征的起源,用于太阳能水分解。电子态密度分析表明,相对于 Zn2V2O7,ZnV2O6 中钒的配位数越高,由于导带和价带中的 VV 和 OO 距离分别较低,导致带离域更多。此外,已经详细讨论了太阳能收集特性(介电函数和光吸收系数)中出现的特征的起源,用于太阳能水分解。
更新日期:2018-04-01
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