5 years ago

Visible Light Photoelectrochemical Properties of PbCrO4, Pb2CrO5, and Pb5CrO8

Visible Light Photoelectrochemical Properties of PbCrO4, Pb2CrO5, and Pb5CrO8
Allen J. Bard, Ki Min Nam, Sung Ki Cho, Hyun S. Park, Heung Chan Lee
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 SO32– 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).

Publisher URL: http://dx.doi.org/10.1021/acs.jpcc.7b03230

DOI: 10.1021/acs.jpcc.7b03230

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.