Ying Peijin, Li Meng, Yu Feilin, Geng Yang, Zhang Liyang, He Junjie, Zheng Yujie, Chen Rong
MOE Key Laboratory of Low-grade Energy Utilization Technologies and Systems, CQU-NUS Renewable Energy Materials & Devices Joint Laboratory, School of Energy & Power Engineering, Chongqing University, Chongqing 400044, China.
Bremen Center for Computational Materials Science, University of Bremen, Am Fallturm 1, 28359 Bremen, Germany.
ACS Appl Mater Interfaces. 2020 Jul 22;12(29):32880-32887. doi: 10.1021/acsami.0c09965. Epub 2020 Jul 9.
Solar-driven interfacial evaporation system is attracting intensive attention for harvesting clean water in the utilization of solar energy. To improve solar-driven interfacial evaporation performance for better application, structuring a solar absorber with high solar-thermal conversion efficiency is critical. Semiconductor materials with stable and economic properties are good candidates as solar absorbers. Semiconductors with a narrow band gap have been proved to offer a broad solar absorption spectrum in the applications of photoelectricity and photocatalysis. However, the correlation between band gap and solar-driven interfacial evaporation performance has not been systematically studied. Herein, TiO is selected as a semiconductive absorber and a reproducible process is developed to fabricate band gap engineered TiO to understand the relationship between the "electronic structure" and the "performance" in the field of solar-driven interfacial evaporation. After the band gap engineering from 3.2 to 2.23 eV, correlative tests of solar-driven interfacial evaporation performance as well as first-principles calculations are employed to study the correlation mentioned above. As a result, we find that a narrower band gap contributes to improved solar-thermal conversion efficiency and the Ti-doped TiO (Ti-TiO) with the narrowest band gap of 2.23 eV outperforms other samples, achieving the highest evaporation rate of 1.20 kg m h (solar-thermal conversion efficiency of 77.1%). Besides, the Ti-TiO also shows the good ability of photocatalytic degradation. This work may provide a way for semiconductor materials to be designed as solar absorbers with higher solar-thermal conversion efficiency and better solar-driven interfacial evaporation performance for applications in clean water harvesting.
太阳能驱动的界面蒸发系统在太阳能利用中获取清洁水方面正吸引着广泛关注。为了提高太阳能驱动的界面蒸发性能以实现更好的应用，构建具有高太阳能-热转换效率的太阳能吸收器至关重要。具有稳定且经济特性的半导体材料是作为太阳能吸收器的良好候选材料。已证明具有窄带隙的半导体在光电和光催化应用中能提供宽广的太阳能吸收光谱。然而，带隙与太阳能驱动的界面蒸发性能之间的相关性尚未得到系统研究。在此，选择TiO作为半导体吸收器，并开发了一种可重复的工艺来制备带隙工程化的TiO，以了解太阳能驱动的界面蒸发领域中“电子结构”与“性能”之间的关系。在将带隙从3.2 eV工程化为2.23 eV之后，采用太阳能驱动的界面蒸发性能相关测试以及第一性原理计算来研究上述相关性。结果，我们发现较窄的带隙有助于提高太阳能-热转换效率，带隙最窄为2.23 eV的Ti掺杂TiO（Ti-TiO）优于其他样品，实现了1.20 kg m⁻² h⁻¹的最高蒸发速率（太阳能-热转换效率为77.1%）。此外，Ti-TiO还表现出良好的光催化降解能力。这项工作可能为将半导体材料设计成具有更高太阳能-热转换效率和更好的太阳能驱动界面蒸发性能的太阳能吸收器提供一条途径，用于清洁水收集应用。
