Impact of chloride surface treatment on nano-porous GaN structure for enhanced water-splitting efficiency

Son, Hoki; Park, Jee Hye; Uthirakumar, Periyayya; Kuznetsov, A. Yu.; Lee, In Hwan

doi:10.1016/j.apsusc.2020.147465

Cited by 31 publications

(13 citation statements)

References 31 publications

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“…Note that defect-assisted recombination would significantly reduce the photocarrier lifetime, and thus lower the water-splitting efficiency. [35] As residual stress is associated with defects in single crystals, Figure 3a Figure 3b are consistent, both of which confirmed that PEC etching will remove defects from GaN and benefit the water-splitting efficiency.…”

Section: Optical Characterizationsupporting

confidence: 65%

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Zheng

Zhao

et al. 2023

Physica Status Solidi (a)

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Photoelectrochemical (PEC) water splitting is a promising approach to generating eco‐friendly hydrogen energy from water. Despite long‐lasting efforts, the existing methods still suffer limitations in the design of photoelectrodes with optimal structures for efficient operation. Herein, a novel porous gallium nitride (PGaN) photoanode decorated with plasmonic Au nanoparticles (AuNPs) is fabricated. After microstructural optimization, this composite photoanode improves the water‐splitting efficiency from 0.036% to 0.30% and exhibits a 2.7 times improvement of the photocurrent density in comparison with the planar GaN photoanode. The significant improvement of the water‐splitting efficiency is attributed to the synergistic combination of the porous structure with the plasmonic AuNPs that greatly benefits electron–hole pairs generation, separation, and charge‐carrier transport. The photoanode is robust and easy to fabricate, and this work provides an idea for future exploration of durable and efficient GaN‐based photoelectrodes.

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Section: Optical Characterizationsupporting

confidence: 65%

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Zheng

Zhao

et al. 2023

Physica Status Solidi (a)

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“…The development of stable and efficient materials for photoelectrochemical (PEC) water splitting to produce hydrogen is one of the challenges in recent years that has arisen from the depleting fossil fuel reserves and rising environmental pollution. − Among others, Group III nitride semiconductors are considered to be promising materials toward water splitting due to their attractive physical properties, appropriate band-gap and band-edge potentials, and stability against corrosion. − The PEC water-splitting studies performed on GaN and its alloy heterostructures have shown active photocatalytic behavior in aqueous solutions under light illumination. − However, the efficiency of GaN and InGaN is reported to be lower due to the high recombination rate of photogenerated charge carriers as well as losses of incident light reflection. , Various approaches such as surface modification or the development of low-dimensional nanostructures, passivation with a cocatalyst, the use of 2D materials, etc., are being adopted for improving the performance of a photocatalyst. ,,− Kim et al showed that GaN film surface nanostructuring, i.e., truncated cone structures, has improved water-splitting efficiency compared to a planar GaN film due to enhanced light trapping and reduced light losses, resulting in enhanced photocatalytic activity . Also, the high surface-area-to-volume ratio provides more active sites for water redox reactions.…”

Section: Introductionmentioning

confidence: 99%

“…The GaN nanostructures fabricated through the PEC etching method have shown significant improvement in energy conversion efficiency, and the photocurrent density increased by 390% compared to that of a planar GaN photoelectrode . Son et al reported that the presurface treatment of a nanoporous GaN photoelectrode with halogen atoms has shown better photocatalytic characteristics compared to an untreated nanoporous GaN. , Varadhan et al reported that molecular beam epitaxy (MBE)-grown GaN nanowires on a silicon (Si) substrate treated with an organic thiol (1,2-ethanedithiol) have improved the photocatalyst efficiency with longer operational stability compared to bare GaN nanowires . The GaN nanowires coated with 2D W x S 1– x and MoS 2 /GaN hybrid structures are also promising photoanode materials with better efficiency for PEC applications. , Bae et al reported a hybrid structure of graphene and MBE-grown GaN nanowires on a Si substrate for the application of water splitting and found a 2-fold increase in the photocurrent density in comparison to pristine GaN nanowires .…”

Section: Introductionmentioning

confidence: 99%

Hybrid Reduced Graphene Oxide/GaN Nanocolumns on Flexible Niobium Foils for Efficient Photoelectrochemical Water Splitting

Ramesh

Tyagi

Aggarwal

et al. 2023

ACS Appl. Nano Mater.

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We present the photoelectrochemical (PEC) watersplitting properties of pristine and reduced graphene oxide (rGO)coated GaN nanocolumns (NCs) on flexible niobium (Nb) metal foils. The structural, optical, and electronic structure analyses of rGOcoated GaN-NCs on Nb foils revealed the formation of a rGO/GaN-NCs hybrid structure. Further, the valence-band studies of pure GaN-NCs shows valence-band maxima at ∼3.0 eV below the Fermi level, which decreased to ∼2.8 eV for rGO/GaN-NCs. The PEC measurement performed on pristine GaN-NCs under standard (1 Sun) conditions shows an effective photocatalytic nature with a photocurrent density of ∼60 μA/cm 2 at 0.8 V (vs Ag/AgCl) in a 1 M oxalic acid electrolyte, which increases to ∼110 μA/cm 2 for rGO/ GaN-NCs. The efficient PEC characteristics of rGO/GaN-NCs are attributed to the effective charge separation/transport of photogenerated carriers. Furthermore, transient photocurrent measurement reveals that hybrid and pristine GaN-NCs on flexible metal foil have a fast and stable photoresponse in an aqueous solution. The development of a hybrid nitride nanostructure-based PEC device on flexible metal foils paves the way toward developing scalable PEC devices for hydrogen production applications.

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“…In particular, most semiconductor photoanodes operate at high oxidation potentials that are suitable for PEC water splitting . Recently, metal nitrides have emerged as a new family of oxide-free photoelectrodes and are attracting the attention of researchers because of their unique intrinsic and extrinsic properties. , In particular, metal nitrides have promising applications in photo(electro)chemical reactions, because of their excellent electronic structure and moderate corrosion resistance. − …”

Section: Introductionmentioning

confidence: 99%

Ni₃(PO₄)₂ Cocatalyst-Supported β–Ga₂O₃/GaN Photoanodes for Highly Stable Solar Water Splitting

Arunachalam

Subhash

Ahn

et al. 2022

ACS Appl. Energy Mater.

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This paper investigated the chemically surface-modified gallium nitride (GaN) films used as photoanodes for photoelectrochemical (PEC) water splitting. Here, the porous GaN is prepared by a simple chemical etching process (referred to as β−Ga 2 O 3 /GaN−10 s, β−Ga 2 O 3 /GaN−30 s, and β−Ga 2 O 3 /GaN−1 min) and then annealed in an air ambient atmosphere at 600 °C to introduce the crystalline monoclinic β−Ga 2 O 3 oxide into the GaN surface. X-ray photoelectron spectroscopy and focused ion beam-high-resolution-transmission electron microscopy studies confirmed the chemically robust Ga−O bonds as well as the formation of highly crystalline β−Ga 2 O 3 with a thickness of 15 nm. Notably, the 15-nm-thick β−Ga 2 O 3 -integrated GaN photoelectrode provided a large photovoltage of ∼1.2 V RHE , resulting in extended band bending for efficient charge separation, leading to efficient PEC water oxidation. This phenomenon reduces the charge recombination in the surface state, protecting semiconductors from chemical corrosion of the pristine GaN film. As expected, the engineered β−Ga 2 O 3 /GaN−30 s photoanode displayed an excellent photocurrent density (J ph ) of 1.2 mA•cm −2 at 1.23 V versus a reversible hydrogen electrode (V RHE ) under a stable working condition, up to 25, 21, and 34% greater than those of the bare GaN, β−Ga 2 O 3 /GaN−10 s, and β−Ga 2 O 3 /GaN−1 min of 0.95, 0.99, and 0.86 mA/cm 2 , respectively, in 0.5 M NaOH alkaline solution. Moreover, nickel phosphate (Ni−Pi) electrocatalysts were supported on the β−Ga 2 O 3 /GaN−30 s photoanode film by a simple photoelectrodeposition method, revealing a J ph of 1.4 mA•cm −2 at 0 V RHE . The superior performance of the Ni−Pi/β−Ga 2 O 3 /GaN photoanode system clearly demonstrates the possibility of highly stable water splitting by the modulation of the reaction kinetic parameters, such as passivation and surface kinetics.

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Impact of chloride surface treatment on nano-porous GaN structure for enhanced water-splitting efficiency

Cited by 31 publications

References 31 publications

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Hybrid Reduced Graphene Oxide/GaN Nanocolumns on Flexible Niobium Foils for Efficient Photoelectrochemical Water Splitting

Ni₃(PO₄)₂ Cocatalyst-Supported β–Ga₂O₃/GaN Photoanodes for Highly Stable Solar Water Splitting

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Impact of chloride surface treatment on nano-porous GaN structure for enhanced water-splitting efficiency

Cited by 31 publications

References 31 publications

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Nanoporous GaN Photoanode Decorated with Plasmonic Au Nanoparticles for Enhanced Solar Water Splitting

Hybrid Reduced Graphene Oxide/GaN Nanocolumns on Flexible Niobium Foils for Efficient Photoelectrochemical Water Splitting

Ni3(PO4)2 Cocatalyst-Supported β–Ga2O3/GaN Photoanodes for Highly Stable Solar Water Splitting

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Product

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Ni₃(PO₄)₂ Cocatalyst-Supported β–Ga₂O₃/GaN Photoanodes for Highly Stable Solar Water Splitting