Ta3N5 nanotube arrays for visible light water photoelectrolysis.
Tantalum nitride (Ta3N5) has a band gap of approximately 2.07 eV, suitable for collecting more than 45% of the incident solar spectrum energy. We describe a simple method for scale fabrication of highly oriented Ta3N5 nanotube array films, by anodization of tantalum foil to achieve vertically oriented tantalum oxide nanotube arrays followed by a 700 degrees C ammonia anneal for sample crystallization and nitridation. The thin walled amorphous nanotube array structure enables transformation from tantalum oxide to Ta3N5 to occur at relatively low temperatures, while high-temperature annealing related structural aggregation that commonly occurs in particle films is avoided. In 1 M KOH solution, under AM 1.5 illumination with 0.5 V dc bias typical sample (nanotube length approximately 240 nm, wall thickness approximately 7 nm) visible light incident photon conversion efficiencies (IPCE) as high as 5.3% were obtained. The enhanced visible light activity in combination with the ordered one-dimensional nanoarchitecture makes Ta3N5 nanotube arrays films a promising candidate for visible light water photoelectrolysis.
Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Xinjian
X
Feng
Thomas J
TJ
Latempa
James I
JI
Basham
Gopal K
GK
Mor
Oomman K
OK
Varghese
Craig A
CA
Grimes
D004572:Electrolysis / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D009584:Nitrogen / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000295:instrumentation*; D013635:Tantalum / Q000737:chemistry* / Q000528:radiation effects; D014159:Transducers; D014867:Water / Q000737:chemistry*
D014867:Water; D013635:Tantalum; D009584:Nitrogen