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Hematite nanostructures are strong candidates for the development of sustainable water splitting technologies. However, major challenges exist in improving charge density and minimizing charge recombination rates for a competitive photoelectrochemical performance based on hematite without compromising sustainability aspects. Here we develop a synthetic strategy to leverage earth-abundant Al3+ and Zr4+ in a dual-chemical modification to synergistically minimize small polaron effects and interfacial charge recombination. The solution-based method simultaneously induces Al3+ doping of the hematite crystal lattice while Zr4+ forms interfacial excess, creating a single-phased homogeneous nanostructured thin film. The engineered photoanode increased photocurrent from 0.7 mA cm-2 for pristine hematite up to 4.5 mA cm-2 at 1.23 V and beyond 6.0 mA cm-2 when applying an overpotential of 300 mV under simulated sunlight illumination (100 mW cm-2). The results demonstrate the potential of dual-modification design using solution-based processes to enable sustainable energy technologies.
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Overcoming scale-up challenges for nanostructured photoelectrodes via one-step interface engineering
Scaling up photoelectrochemical (PEC) devices for green hydrogen production is a significant challenge that requires robust and cost-effective production methods. In this study, hematite photoelectrodes has been synthesized using a cost-effective polymeric precursor solution, resulting in homogeneous ultra-thin films (~125 nm) with areas up to 200 cm2. We observed a substantial photocurrent drop as photoelectrode area increases, addressed by modifying the precursor solution with Hf4+. This modification improves the morphology and films adherence, leading to simultaneous grain|grain interface segregation and a modified FTO|hematite interface. As a result, film conductivity increases, reducing the photocurrent drop at larger photoelectrode areas. The improved charge separation and surface charge injection efficiencies allows a homogeneous photocurrent of 1.6 mA cm⁻2 at 1.45V across a 15.75 m2 electrode area, using less than 70 μg of photoactive material. Cost analysis study indicates that this low-energy fabrication method is a significant step forward in green hydrogen production, contributing to sustainable and efficient green hydrogen technologies.
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- PAR ID:
- 10516629
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- International Journal of Hydrogen Energy
- Volume:
- 58
- Issue:
- C
- ISSN:
- 0360-3199
- Page Range / eLocation ID:
- 1138 to 1148
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.ijhydene.2024.01.221
