Bismuth vanadate (BiVO_4) as counter electrode in the newly developed catalysis zone of modified cadmium sulfide (CdS) sensitized solar cell for hydrogen production

摘要

Recently we developed a modified quantum dot dyes sensitized solar cell (QD-DSSC) having catalysis zone extension for hydrogen production. The DSSC section comprised of CdS sensitized highly order Titanium dioxidenanotube (CdS-HOTN) immobilized on Ti plate, Na_2S/S containing electrolyte, and Pt covered SnO-F (fluorine doped tin oxide) glass plate (hence Pt/SnO-F/Glass). While the catalysis zone comprised of an extension of Ti support, as cathode, and the respected counter electrode was an extension of SnO-F glass, which was covered by BiVO_4 film, both from respected DSSC section. In this presentation, we will focus on the role of the BiVO_4 in our newly developed system. The bismuth vanadate was prepared by co-precipitation method with ammonia and calcination to obtain a fine powder. The BiVO_4 fine powder were then deposited onto SnO-F glass plate and characterized by FT-IR, UV-vis diffused reflectance spectroscopy, SEM and X-ray diffraction. The characterization results revealed that the BiVO_4 film, typically, has a band gap of 2.35 eV, characteristic of IR peaks represent the -V-O-, and -Bi-O-V-bonds, having a crystal phase as BiVO_4 monoclinic scheelite with a typically crystallite size of 74.06 nm. The photo-electro-chemical properties of the BiVO_4 film photo-anode was investigated by a linear sweep voltammetry and multi pulse amperometry, which revealed that the current response under the visible light was 0.03 mA/cm~2. Further investigation when the BiVO_4 film was incorporated into the modified QD-DSSC, the system (catalysis zone section), under solely visible light, was able to split the water into hydrogen and molecular oxygen. A brief discussion of the newly developed modified QD-DSSC, especially on the role of BiVO_4 counter electrode in the catalysis zone will be presented, to gain a better insight in our new type artificial photosynthesis.