InGaN/GaN Multiple Quantum Well Photoanode Modified with Cobalt Oxide for Water Oxidation

Abstract

Indium gallium nitride (InGaN) is an attractive semiconductor, with a tunable direct bandgap for photoelectrochemical water splitting, but it corrodes in aqueous electrolytes. Cobalt oxide (CoOx) is a promising co-catalyst to protect photoelectrodes and to accelerate the charge transfer. CoOx is earth-abundant and stable in extremely alkaline conditions and shows high activity for the oxygen evolution reaction (OER). In this work, we demonstrate that CoOx directly deposited onto InGaN/GaN multiple quantum wells photoanodes exhibits excellent activity and stability in a strong alkaline electrolyte, 1M NaOH (pH=13.7), for water oxidation up to 28 hours, while a reference sample without the catalyst degraded rapidly in the alkaline electrolyte. Under simulated solar illumination, the CoOx-modified InGaN/GaN quantum well photoanode showed a high photocurrent density of 1.26 mA cm-2 at 1.23 V and an onset potential of-0.03 V versus a reversible hydrogen electrode.

Strategies for Semiconductor/Electrocatalyst Coupling toward Solar‐Driven Water Splitting

“…ALD enables conformal deposition of a range of transition metal oxides such as CoO x , and NiO x , which can be used as effective catalysts in PEC water splitting. Moreover, the crystal structure and stoichiometry of the deposited oxide layers can be tuned by adjusting the deposition conditions.…”

“…On this basis, they constructed a SiO x /n‐Si photoanode loaded with a double‐layered ALD CoO x film (CoO and Co 3 O 4 ), which exhibited a J sc of 3.5 mA cm −2 , a value twofold higher than that of the CoO‐modified SiO x /n‐Si photoanode. Besides Si, ALD‐derived CoO x films were also reported to couple with other semiconductor photoanodes, e.g., BiVO 4 , InGa/GaN, and Fe 2 O 3 , and enhanced PEC performance was observed in all cases.…”

Multifunctional WO3/NiCo2O4 heterojunction with extensively exposed bimetallic Ni/Co redox reaction sites for efficient photoelectrochemical water splitting

“…The development of clean energy is of far-reaching significance to alleviate the energy and environmental crisis caused by the application of traditional energy in the world and other human activities. [1][2][3][4][5][6][7] Among the many alternative clean energy sources for fossil energy, hydrogen energy has excellent application prospects due to the advantages of rich reserves, high heating value and pollution-free. [8,9] Photoelectrochemical (PEC) water splitting is a promising method for converting endless solar energy into available hydrogen energy in an environmentally friendly way.…”

Modulating Surface/Interface Structure of Emerging InGaN Nanowires for Efficient Photoelectrochemical Water Splitting

“…onto the photoelectrode is the most common strategy to enhance the charge transfer and facilitate water redox kinetics (large k tran ). [ 26,44,85,138,139 ] Kibria et al. have studied PEC performance of various multiband InGaN/GaN NWs heterostructures decorated with Rh/Cr 2 O 3 core/shell nanoparticles.…”