Enabling an integrated tantalum nitride photoanode to approach the theoretical photocurrent limit for solar water splitting

Abstract

The integrated architecture enables the Ta3N5photoanode to approach the theoretical photocurrent limit for solar water splitting.

Tantalum nitride films integrated with transparent conductive oxide substrates via atomic layer deposition for photoelectrochemical water splitting

“…1a. This performance falls short of the recent report by Li and coworkers, 24 who reported a photocurrent density of ∼12.1 mA cm –2 at 1.23 V vs. RHE with a photocurrent onset potential of ∼0.7 V vs. RHE for the electrode prepared on a Ta foil which was nitridized under ammonia at 950 °C for 6 h. Van de Krol et al also recently studied the formation of Ta 3 N 5 as a function of ammonolysis conditions on Pt foil. 14 The maximum photocurrent density of ∼1.1 mA cm –2 at 1.23 V vs. RHE with an onset photocurrent potential of ∼0.9 V vs. RHE was found for the Ta 3 N 5 film prepared at 800 °C for 10 h with the addition of IrO 2 cocatalysts.…”

“…23 Strikingly, Li and coworkers recently reported a Ta 3 N 5 photoanode on Ta foil prepared by ammonolysis at 950 °C for 6 h that produced a photocurrent density of ∼12.1 mA cm –2 at 1.23 V vs. RHE with a photocurrent onset potential of ∼0.7 V vs. RHE. 24 …”

Photoelectrode for water splitting: Materials, fabrication and characterization

“…The state-of-the-art photocurrent of Ta 3 N 5 has been reported to be 12 mA cm −2 , suggesting the outstanding optoelectronic property of Ta 3 N 5 semiconductor [50]. In the Ta 3 N 5 electrode, TiO 2 was deposited to block back electron-hole recombination, while ferrihydrate was used to capture holes for the further catalytic reaction on the molecular catalyst (Fig.…”

Enhanced Hydrogen Evolution under Simulated Sunlight from Neutral Electrolytes on (ZnSe)0.85(CuIn0.7Ga0.3Se2)0.15 Photocathodes Prepared by a Bilayer Method

“…However, there is still a large gap between this theoretical value and the experimentally observed value, which is 7.1 mA cm À2 at 0 V RHE . For this reason, further investigations regarding the modification of (ZnSe) 0.85 (CIGS) 0.15 photocathodes are required, with the goal of enhancing the photocurrent.Various modifications of photoelectrodes have been found to be effective at increasing the photocurrent, including forming multilayer structures incorporating a p-n junction, [8][9][10][11] controlling the defect density in the bulk or at the interface, [12][13][14] increasing the grain size, [15,16] and controlling the resistivity through doping. [17][18][19] The most effective strategy depends on the actual state of the photoelectrode, such as the degree of crystallinity of the absorber, or the semiconductor properties, or quality of the various interfaces.…”