PbCrO 4，Pb 2 CrO 5和Pb 5 CrO 8的可见光电化学性能,The Journal of Physical Chemistry C

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PbCrO ₄，Pb ₂ CrO ₅和Pb ₅ CrO _8的可见光电化学性能
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2017-08-16 00:00:00 , DOI: 10.1021/acs.jpcc.7b03230
Heung Chan Lee ₁ , Sung Ki Cho ₂ , Hyun S. Park ₃ , Ki Min Nam ₄ , Allen J. Bard ₅

Affiliation

使用扫描电化学显微镜（SECM）快速筛选具有铅和铬的各种组合的铬酸铅的光活性。在快速筛选研究中，Pb / Cr比为2：1的金属氧化物点电极在用不同组成制备的半导体中表现出最高的光活性。通过组合筛选进一步研究了PbCrO ₄，Pb ₂ CrO ₅和Pb ₅ CrO ₈薄膜电极的光活性和电化学性能。在体电极测量中，Pb ₂ CrO ₅体电极对SO _3的光电流最高，为0.23 mA / cm ²在100 mW / cm ^2的UV-可见光照射下，相对于Ag / AgCl在0.4 V下发生²^–氧化。Pb ₂ CrO ₅具有可见光活性，吸收波长高达550 nm，在340 nm波长处的入射光子电流转换效率（IPCE）为10％。在紫外可见吸收光谱中观察到的起始波长随着铬酸铅中铅含量的增加而增加。对于PbCrO ₄，Pb ₂ CrO ₅和Pb ₅ CrO ₈，光学获得的直接带隙从2.38到2.25 eV减小。，分别。但是，对于所有三种铬酸铅，IPCE中出现的起始波长为2.26±0.02 eV，在较长波长的光照射下光电流微不足道。结果表明，更多的Pb 6s轨道形成带间状态，从而增加了铬酸铅中的光学跃迁。PbCrO ₄，Pb ₂ CrO ₅和Pb ₅ CrO ₈的能带结构也通过电化学分析和紫外光电子能谱（UPS）确定。

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Visible Light Photoelectrochemical Properties of PbCrO4, Pb2CrO5, and Pb5CrO8

Photoactivities of lead chromates with various combinations of Pb and Cr are rapidly screened using scanning electrochemical microscopy (SECM). In the rapid screening investigation, the metal oxide spot electrode with a Pb/Cr ratio of 2:1 exhibits the highest photoactivity among the semiconductor prepared with different compositions. The photoactivity and electrochemical properties of thin-film electrodes of PbCrO₄, Pb₂CrO₅, and Pb₅CrO₈ are further studied following the combinatorial screening. In the bulk electrode measurements, the Pb₂CrO₅ bulk electrode displays the highest photocurrent of 0.23 mA/cm² for SO₃^2– oxidation at 0.4 V vs Ag/AgCl under 100 mW/cm² UV–vis light irradiation. Pb₂CrO₅ presents visible light activity with an absorption wavelength up to 550 nm and an incident photon to current conversion efficiency (IPCE) of 10% at the wavelength of 340 nm. The onset wavelength observed in the UV–vis absorption spectrum increases with increasing Pb contents in lead chromates. Optically obtained direct band gaps decreased from 2.38 to 2.25 to 2.07 eV for PbCrO₄, Pb₂CrO₅, and Pb₅CrO₈, respectively. However, the onset wavelength that appeared in IPCE is 2.26 ± 0.02 eV for all three lead chromates where the photocurrent under longer wavelength light irradiation is insignificant. The results imply that more Pb 6s orbitals form interband states, increasing optical transitions in lead chromates. The band structures of PbCrO₄, Pb₂CrO₅, and Pb₅CrO₈ are also determined by electrochemical analyses and ultraviolet photoelectron spectroscopy (UPS).

更新日期：2017-08-16

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