Photoelectrochemical (PEC) water splitting using photocatalysts is a promising technique to convert solar energy into chemical fuels, namely, hydrogen and oxygen. Ta3N5 is a visible-light-responsive photocatalyst and its practical application requires photoanodes with good performance, uniformity, and large area. Though there are several reports on the fabrication of Ta3N5 photoanodes, there still exist problems such as erosion, impurities, and cracks, preventing the development of high-quality photoanodes over large areas. To overcome this problem, we demonstrate a new method to fabricate Ta3N5 photoanodes using evaporated TaF5 as the source of tantalum. The as-synthesized Ta3N5 layers were well-formed with columnar crystals; they were found to be uniformly deposited on different large-area substrates and worked as efficient active photoanodes for PEC water splitting. These results could be achieved due to the intrinsically low boiling point and high reactivity of TaF5. We believe the new insights obtained from this study on TaF5 as a precursor for nitrides can be used to develop high-quality Ta-based photoanodes over different substrates with large areas.
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