Editors' Choice—The Photoelectrochemical and Photocatalytic Properties of Tantalum Oxide and Tantalum Nitride

Abstract

The surfactant-assisted synthesis of tantalum oxide nanoparticles (Ta 2 O 5 ), its subsequent nitridation to form tantalum nitride (Ta 3 N 5 ), and the evaluation of the photoactivity of these nanoparticles, are presented. The surface, optical, and compositional characterization of the in-house synthesized photocatalysts indicate spherical nanoparticles with φ = 30 nm Ta 2 O 5 and φ = 30 nm Ta 3 N 5 with the latter photocatalysts showing absorbance onset at ∼ 630 nm. Photoelectrochemical analysis of the various photocatalyst films using chronoamperometry, linear sweep voltammetry, and impedance measurements attribute an improved photoactivity with the in-house catalysts to better charge generation, transport, and utilization. Initial results using Ta 2 O 5 and Ta 3 N 5 demonstrate photocatalytic activity toward conversion of colored pollutants.

A Selective Synthesis of TaON Nanoparticles and Their Comparative Study of Photoelectrochemical Properties

“…Further, from our previous studies, the use of glacial acetic acid has indicated the formation of oxides with a high surface area that maintain stability [64]. Besides, ethoxide precursors have reportedly been known for interactions resulting in stable complexes with metal cations in acidic media [63,65]. Based on these references, in our previous work, we investigated the use of an ethoxide precursor with glacial acetic acid implementing the sol-gel process [63].…”

“…Besides, ethoxide precursors have reportedly been known for interactions resulting in stable complexes with metal cations in acidic media [63,65]. Based on these references, in our previous work, we investigated the use of an ethoxide precursor with glacial acetic acid implementing the sol-gel process [63]. We studied the complete nitridation of as-synthesized Ta 2 O 5 crystals in the same work to achieve single phase Ta 3 N 5 , and herein we present a novel partial nitridation technique to achieve single phase TaON.…”

“…Traditionally, the common route of synthesizing TaON has been the gas phase nitridation of corresponding oxides at high temperature. Ammonia, the most common nitrogen source used in such synthesis routes, is shown to produce the fully reduced form of Ta 2 O 5 (i.e., Ta 3 N 5 ) [63,[66][67][68] while moist ammonia is reported to thermodynamically support the yield of TaON [69][70][71]. Challenge of controlling the precise flowrate of multiple fluids in such approaches often leads to the formation of various mixed (oxy)nitrides.…”

Phase comparison and equation of state for Ta2O5

“…Tantalum pentoxide (Ta 2 O 5 , also known as tantala or tantite) has a long list of desirable properties, including a wide band gap, [1] high dielectric constant [2], low optical absorptivity [3], and high nonlinear refractive index [4]. These have resulted in its incorporation into a variety of technologies, including capacitors [5], optical coatings [6], biochemically inert devices [7], and photonic integrated circuits [8] among other applications.…”

Tantalum oxynitride nanotube film arrays for unconventional nanostructured photo-electrodes active with visible light

“…The conversion of oxides to oxynitrides is a well-established method for particulate photocatalysts to shift the band gap within the visible region [34][35][36]. Among oxynitrides, Tantalum OxyNitride (TaOxNy) show interesting performances [37][38][39][40]. Semiconductors such as TaON [41] and Ta3N5 [42,43] possess an interesting band structure,, in the ~2.2-2.7 eV range depending on the amount of N present in the structure, allowing a theoretical solar-to-hydrogen efficiency as high as 15.9% under AM 1.5 G 100 mW•cm -2 irradiation [43].…”