Rapid screening of bivo₄-based photocatalysts by scanning electrochemical microscopy (SECM) and studies of their photoelectrochemical properties

A picoliter solution dispenser was used to fabricate various n-type BiVO₄ based photocatalyst arrays having different compositions and a scanning electrochemical microscopy (SECM) technique modified by replacing a normal ultramicroelectrode with an optical fiber was used for fast screening of the effective photocatalysts for Na₂SO₃ (as a sacrificial reductant) and water oxidation. Bi/V/W oxide with a ratio of 4.5:5:0.5 showed -4.6 - higher photocurrent than Bi/V oxide without W and this result was confirmed with bulk film studies. Preliminary characterization (XRD, XPS, and EIS) was also performed for these catalysts. This material was tested for photoelectrochemical water oxidation with a Pt ring optical fiber to detect the product (O₂) of photoelectrochemical oxidation reaction.