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Engineers at Rice University have achieved a groundbreaking standard in green hydrogen technology by efficiently converting sunlight into hydrogen using a device that combines next-generation halide perovskite semiconductors with electrocatalysts. This innovative, durable, cost-effective, and scalable device represents a significant advancement in clean energy, potentially serving as a versatile platform for various chemical reactions that convert solar-harvested electricity into fuels.
The research was led by Aditya Mohite’s lab, specializing in chemical and biomolecular engineering, which developed an integrated photoreactor as a key element of the device. A crucial feature of this design is an anticorrosion barrier that effectively insulates the semiconductor from water without hindering electron transfer. Published in Nature Communications, the study revealed an impressive 20.8% solar-to-hydrogen conversion efficiency for the device.
Austin Fehr, one of the study’s lead authors and a doctoral student in chemical and biomolecular engineering, highlighted the significance of their work in overcoming a major obstacle in clean energy production. “Using sunlight as an energy source to manufacture chemicals is one of the largest hurdles to a clean energy economy. Our goal is to build economically feasible platforms that can generate solar-derived fuels. Here, we designed a system that absorbs light and completes electrochemical water-splitting chemistry on its surface.”
This innovative device is referred to as a photoelectrochemical cell, where the absorption of light, conversion into electricity, and use of electricity to power a chemical reaction occur within the same device. Previously, low efficiencies and the high cost of semiconductors hindered the widespread use of photoelectrochemical technology for green hydrogen production.
The breakthrough by the Mohite lab and its collaborators turned their highly-competitive solar cell into a reactor capable of utilizing harvested energy to split water into oxygen and hydrogen. The major challenge involved overcoming the extreme instability of halide perovskites in water, which resulted in coatings disrupting the semiconductors’ function or damaging them.
After extensive trials and iterations, the team successfully developed a winning solution. “Our key insight was that you needed two layers to the barrier, one to block the water and one to make good electrical contact between the perovskite layers and the protective layer,” Fehr explained. “Our results represent the highest efficiency for photoelectrochemical cells without solar concentration and the best overall for those using halide perovskite semiconductors.”
The device’s significance lies in its relatively inexpensive semiconductor, a departure from historically expensive semiconductors in similar systems. With further improvements in stability and scalability, this technology has the potential to usher in the hydrogen economy, transforming the way we produce fuels from solar energy instead of fossil fuels.
The researchers hope that this platform will drive various electrons to fuel-forming reactions, using abundant feedstocks and solely relying on sunlight as the energy source. The successful integration of green hydrogen technology could pave the way for a sustainable energy transition, driving us closer to a cleaner and more sustainable future.
Reference: “Integrated halide perovskite photoelectrochemical cells with solar-driven water-splitting efficiency of 20.8%” by Austin M. K. Fehr, Ayush Agrawal, Faiz Mandani, Christian L. Conrad, Qi Jiang, So Yeon Park, Olivia Alley, Bor Li, Siraj Sidhik, Isaac Metcalf, Christopher Botello, James L. Young, Jacky Even, Jean Christophe Blancon, Todd G. Deutsch, Kai Zhu, Steve Albrecht, Francesca M. Toma, Michael Wong, and Aditya D. Mohite, 26 June 2023, Nature Communications.
Rice graduate students Ayush Agrawal and Faiz Mandani are the study’s lead authors alongside Fehr. The work was also partly authored by the National Renewable Energy Laboratory, operated by the Alliance for Sustainable Energy LLC for the Department of Energy under Contract DE-AC36-08GO28308.
Mohite is an associate professor of chemical and biomolecular engineering and the faculty director of the Rice Engineering Initiative for Energy Transition and Sustainability, or REINVENTS. Wong is the Tina and Sunit Patel Professor in Molecular Nanotechnology, chair and professor of chemical and biomolecular engineering, and a professor of chemistry, materials science, nanotechnology, and civil and environmental engineering.
The Department of Energy (DE-EE0008843), SARIN Energy Inc., and Rice’s Shared Equipment Authority supported the research.