Photoelectrochemical Oxidation of Water Using BaTaO₂N Photoanodes Prepared by Particle Transfer Method

Abstract

A photoanode of particulate BaTaO2N fabricated by the particle transfer method and modified with a Co cocatalyst generated a photocurrent of 4.2 mA cm(-2) at 1.2 V(RHE) in the photoelectrochemical water oxidation reaction under simulated sunlight (AM1.5G). The half-cell solar-to-hydrogen conversion efficiency (HC-STH) of the photoanode reached 0.7% at 1.0 V(RHE), which was an order of magnitude higher than the previously reported photoanode made from the same material. The faradaic efficiency for oxygen evolution from water was virtually 100% during the reaction for 6 h, attesting to the robustness of the oxynitride.

Chalcopyrite Thin Film Materials for Photoelectrochemical Hydrogen Evolution from Water under Sunlight

“…Various types of oxide-and (oxy)nitride-based n-type semiconductor materials, such as hematite [6][7][8], vanadate [9,10], the GaN:ZnO solid solution [11], nitrides [12,13], and oxynitirides [14,15] have been reported as photoanode materials. In the case of the photoanode, self-oxidation makes it difficult to utilize non-oxide materials.…”

Low-temperature synthesis of BaTaO₂N by an ammonothermal method

“…Similar to other solution processes, the ammonothermal synthesis resulted in particles with smooth surface, whereas porous particles were generally observed when the oxynitride was synthesized from an oxide precursor. 4) Moreover, particles with different sizes and shapes were observed, thereby suggesting that grain growth and nucleation simultaneously proceeded during the reaction. To overcome this issue, it seems necessary to carefully optimize other reaction conditions such as the heating and cooling rates.…”

“…4) Several approaches have been developed with the aim to enhance the photocatalytic activity of BaTaO 2 N; namely, band engineering using a BaTaO 2 NBaZrO 3 solid solution, 5) and hetero-valent cation doping. 6) In the conventional synthesis method, BaTaO 2 N is obtained by heating an oxide precursor (e.g., Ba 2 ) under flowing ammonia above ca.…”

Enhanced solar photocurrent of LaTaON2 photoanodes via electrochemical treatment

“…However, the availability of high efficient photoelectrodes is now hampering the realization of this technique [2]. Tremendous amount of effort has been paid to implement the full photoelectrochemical performances ofBiVO 4 , Fe 2 O 3 , WO 3 and TiO 2 [3]. (Oxy)nitrides, which possess ideal band structures and promising high solarto-hydrogen (STH) efficiencies, may become the alternative photoanode material to address this dilemma [3].…”

“…To accelerate the kinetic process of water oxidation, surface modification of oxygen evolution catalyst is adopted to improve thesolar water-splitting current of (oxy)nitride photoanode [4][5][6]. On the other hand, surface recombination centre on the photoanodes has been revealed by the transient absorption spectroscopy [7].…”