Exploring the Different Roles of Particle Size in Photoelectrochemical and Photocatalytic Water Oxidation on BiVO4

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

35 Scopus Citations
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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)28607-28614
Journal / PublicationACS Applied Materials and Interfaces
Volume8
Issue number42
Online published27 Sep 2016
Publication statusPublished - 26 Oct 2016
Externally publishedYes

Abstract

Water oxidation on visible-light-active bismuth vanadate (BiVO4) has commonly been demonstrated to be viable in powder suspension (PS) and particulate photoelectrochemical (PEC) systems. Here, we demonstrate that particle size reduction, which is known to be efficacious in promoting charge carrier extraction and boosting surface active sites, has an opposite effect on BiVO4's photoactivity in the two systems. With three BiVO4 samples of distinctive particle sizes, smaller BiVO4 particle size is shown to be beneficial for enhancing PEC photocurrent generation, but deleterious for photocatalytic O2 evolution on suspended BiVO4. Such contrary effect of particle size in the PEC and PS systems is revealed to be due to the different governing factors of the systems: charge transport in the former and charge separation in the latter. Smaller particle size was found to enrich the interparticle and the particle/FTO substrate contacts which improve charge transport and charge collection efficiency in BiVO4 particulate electrode. On the contrary, larger particle size is necessary for improved photocatalytic O2 evolution because of increased crystallinity and greater band bending, which are essential for charge separation.

Research Area(s)

  • bismuth vanadate, particle size, photocatalysis, photoelectrochemistry, water oxidation