Photoelectrochemical hydrogen generation using graded In-content InGaN photoelectrode structures

Ohkawa, Kazuhiro; Uetake, Yusuke; Velazquez-Rizo, Martin; Iida, Daisuke

doi:10.1016/j.nanoen.2019.03.011

Cited by 21 publications

(10 citation statements)

References 36 publications

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“…Two GaxIn1-xN samples A and B with a thickness of 110 nm were grown on n-GaN layers on sapphire substrates by a metalorganic vapor phase epitaxy system [31,32]. Sample A has an alloy composition x = 0.84 for the crystal under the pseudomorphic condition.…”

Section: Methodsmentioning

confidence: 99%

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

Okamoto

Saito

Ito

et al. 2020

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystem

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Local heat transport in two GaxIn1-xN/GaN-heterostructures on sapphire substrates is investigated by microscopic Raman imaging using two lasers of 532 nm (Raman observation) and 325 nm (heat generation and Raman observation), which enables the separation of heat generation and Raman observation positions. It is found that E2(high) and A1(LO) modes of the Ga0.84In0.16N layer exhibit mutually different characteristics, which indicates the analysis of the occupation of the A1(LO) mode is available. E2(high) mode of the GaN layer observed by the 532-nm laser reveals that the transport of the heat energy generated in the Ga0.84In0.16N layer to the GaN under layer is blocked in the high-density area of misfit dislocation in the vicinity of the heterointerface.

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Section: Methodsmentioning

confidence: 99%

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

Okamoto

Saito

Ito

et al. 2020

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystem

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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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“…In one of their works, AlOtaibi and co‐workers [33] report that the photochemical reduction of CO 2 to CH 3 OH, CO, and CH 4 can be achieved on the pristine GaN(100), while a nearly 50‐fold increase of the CO 2 conversion rate is obtained by the incorporation of Mg doping. Moreover, In x Ga 1‐x N has been also proposed as highly promising photocatalysts for solar fuel applications, including the CO 2 ‐to‐CO and hydrocarbons, in solutions with a wide pH range [34–42] . Motivated by these promising results, in a preliminary work, [24] we have investigated the photocatalytic activity of the undoped GaN and GaN doped with one single Mg atom, along with the CO 2 reduction to methanol.…”

Section: Introductionmentioning

confidence: 99%

Gallium Nitride‐based Materials as Promising Catalysts for CO₂ Reduction: A DFT Study on the Effect of CO₂ Coverage and the Incorporation of Mg Doping or Substitutional In

et al. 2022

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Catalytic CO 2 conversion to fuels and chemicals is important for mitigating the climate change and reducing the dependence on fossil resources. In order to achieve this goal on a large industrial level, effective catalysts need to be developed. Among them, gallium nitride (GaN) and related Mg-doped and In-alloyed systems have been proven as efficient materials for the reduction of highly stable CO 2 molecules. This work presents a density functional theory (DFT) investigation, performing periodic boundary condition (PBC) calculations which allow to employ a more extended surface for a detailed analysis of the CO 2 coverage, and the effect of Mg doping and In alloying on the CO 2 adsorption and its conversion to CO. The results show the great potential of GaN(100) surfaces to simultaneously bind and strongly activate multiple CO 2 molecules, which is a crucial aspect for an efficient CO 2 conversion process. Moreover, the presence of Mg-dopant on the top layer is found to be more beneficial for the CO 2 adsorption and activation with respect to both the pristine and In-alloyed system, and this effect is further improved by the inclusion of a second impurity on the top layer. In line with the previous experimental findings, these calculations support the potential of pristine GaN(100) to catalyze the CO 2 -to-CO reduction. The results presented here offer crucial information for the development of more efficient and selective catalysts for the CO 2 reduction.

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Photoelectrochemical hydrogen generation using graded In-content InGaN photoelectrode structures

Cited by 21 publications

References 36 publications

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

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

Gallium Nitride‐based Materials as Promising Catalysts for CO₂ Reduction: A DFT Study on the Effect of CO₂ Coverage and the Incorporation of Mg Doping or Substitutional In

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Photoelectrochemical hydrogen generation using graded In-content InGaN photoelectrode structures

Cited by 21 publications

References 36 publications

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

Local Heat Energy Transport Analyses in Gallium-Indium-Nitride/Gallium Nitride Heterostructure by Microscopic Raman Imaging Exploiting Simultaneous Irradiation of Two Laser Beams

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

Gallium Nitride‐based Materials as Promising Catalysts for CO2 Reduction: A DFT Study on the Effect of CO2 Coverage and the Incorporation of Mg Doping or Substitutional In

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

Gallium Nitride‐based Materials as Promising Catalysts for CO₂ Reduction: A DFT Study on the Effect of CO₂ Coverage and the Incorporation of Mg Doping or Substitutional In