Open top anodic Ta3N5 nanotubes for higher solar water splitting efficiency

TL;DR

This paper reports the fabrication of open-top Ta3N5 nanotubes via anodic oxidation of Ta2O5, which enhances solar water splitting efficiency by providing a high photoelectrochemical response under illumination.

Contribution

It introduces a novel method to produce open-top Ta3N5 nanotubes with improved adherence and homogeneity for solar water splitting applications.

Findings

Achieved 4 μm long nanotubes with open top morphology.

Converted Ta2O5 nanotubes to Ta3N5 with enhanced photoelectrochemical performance.

Obtained a current response of 4.7 mA/cm² at 1.23 V vs RHE under illumination.

Abstract

In the present work we grow self-organized Ta2O5 nanotube layers in a H2SO4/NH4F electrolyte at various elevated temperatures. Under optimized conditions we obtain 4 {\mu}m long nanotubes that are well adherent to the substrate and can be grown very homogenous over large surface areas. Moreover, the key advantage of this approach is that an open top morphology (initiation layer free) is obtained. After a suitable conversion treatment in NH3 atmosphere Ta3N5 nanotubes are obtained, that after (Co-Pi+Co(OH)x) modification provide, under AM 1.5G illumination conditions, a photoelectrochemical current response of 4.7 mA cm-2 at 1.23 V vs RHE.