LaCl3 Flux mediated Ta3N5 Planar Photoanode for Solar Water Oxidation

Abstract Ta3N5 is a promising candidate for photoelectrochemical (PEC) water splitting. Recently gratifying photocurrents have been reported through various advanced techniques. However, obtaining high performance Ta3N5 photoanode prepared by direct oxidation and nitridation remains challenging. In this work, efficient Ta3N5 photoanode was fabricated on Ta foil by direct oxidation and nitridation method with LaCl3 flux mediated treatment. The highest photoresponse (8.2 mA cm-2 @ 1.23 VRHE) for direct oxidized and nitrided Ta3N5 is achieved with the help of LaCl3 flux, which is nearly doubled compared to the untreated counterparts. Theoretical analysis suggests an interfacial charge transfer in LaTaON2/Ta3N5 heterostructure and significant increase in carrier concentration on La doped Ta3N5 surface. The introduction of LaCl3 flux brings a new look to this traditional method and it may potentially be applied to large area and low cost photoanodes.