Enhanced photoelectrochemical water splitting behaviour of tuned band gap CdSe QDs sensitized LaB6

Abstract

We report the fabrication of tuned band gap quantum dots sensitized LaB<inf>6</inf> hybrid nanostructures and their application as a photoanode for photoelectrochemical water splitting. The lanthanum hexaboride (LaB<inf>6</inf>) obtained by molten salt electrolysis method is sensitized with different sized CdSe quantum dots, which form a multiple-level hierarchical heterostructure and such design enhance the light absorption and charge carrier separation, which in turn showed higher photocurrent density compared to that of pristine LaB<inf>6</inf>. When LaB<inf>6</inf> is sensitized with CdSe quantum dots of different band gaps, which have the absorption in the green and red (530 and 605 nm) regions in visible light, developed a ten times higher photocurrent density (11.0 mA cm-2) compared to that of pristine LaB<inf>6</inf> (0.5 mA cm-2 at 0.75 V vs. Ag/AgCl) in 1 M Na<inf>2</inf>S electrolyte under illumination. These results prove that the tuned band gap quantum dots sensitized LaB<inf>6</inf> heterostructures are an ideal candidate for a photoanode in solar water splitting applications. © © 2017 American Scientific Publishers All rights reserved.