Engineers develop groundbreaking technology to turn sunlight into hydrogen

Rice University engineers have made a groundbreaking advancement in clean energy technology, successfully turning sunlight into hydrogen with unprecedented efficiency. They achieved this feat by combining cutting-edge halide perovskite semiconductors with electrocatalysts in a single, durable, cost-effective, and scalable device.

The breakthrough technology has immense potential for clean energy applications, as it can be used as a platform for various chemical reactions that convert solar-harvested electricity into fuels. This development was led by the lab of chemical and biomolecular engineer, Aditya Mohite.

Their integrated photoreactor is equipped with an anticorrosion barrier that effectively insulates the semiconductor from water without hindering the transfer of electrons. This is a critical factor in achieving the impressive 20.8% solar-to-hydrogen conversion efficiency, as reported in the study published in Nature Communications.

A chemical and biomolecular engineering doctoral student, Austin Fehr, who is one of the lead authors of the study, emphasized the importance of using sunlight to produce chemicals for a clean energy economy. Their goal is to create economically viable platforms capable of generating solar-derived fuels. The system they designed efficiently absorbs light and facilitates electrochemical water-splitting chemistry on its surface.

The device is referred to as a photoelectrochemical cell, as it performs light absorption, electricity conversion, and chemical reactions all within the same device. In the past, low efficiencies and high semiconductor costs have limited the application of photoelectrochemical technology for green hydrogen production.

However, the team’s device stands out because of its exceptional efficiency and use of a highly affordable semiconductor. To achieve this, the Mohite lab and their collaborators transformed their competitive solar cell into a reactor capable of utilizing harvested energy to split water into oxygen and hydrogen. They overcame the challenge of halide perovskites’ instability in water by developing coatings that effectively protected the semiconductors without compromising their function.

A photoreactor developed by Rice University’s Mohite research group and collaborators achieved a 20.8% solar-to-hydrogen conversion efficiency. Credit: Gustavo Raskoksy/Rice University

Michael Wong, a Rice chemical engineer and co-author of the study, revealed that they spent the past two years experimenting with various materials and techniques, but initial attempts failed to achieve their desired results. However, their perseverance paid off when they finally discovered a winning solution.

Their breakthrough came from the realization that a two-layer barrier was necessary: one layer to block water and another to establish a good electrical connection between the perovskite layers and the protective layer. This insight led to remarkable results, with the highest efficiency ever recorded for photoelectrochemical cells without solar concentration, and the best overall performance for devices using halide perovskite semiconductors.

Traditionally, this field had been dominated by costly semiconductors, making it economically unfeasible. But now, with this novel barrier design, the researchers believe they have found a path to commercial viability for such devices for the first time ever.

The versatility of their barrier design was demonstrated as it worked effectively with various reactions and different semiconductors, making it applicable across numerous systems. The researchers are optimistic that these systems can be a platform for driving multiple electrons-to-fuel reactions using abundant feedstocks and sunlight as the sole energy input.

Aditya Mohite, another co-author and chemical and biomolecular engineer, expressed hope that with further enhancements in stability and scalability, this technology could revolutionize the hydrogen economy, transforming the way we produce things from fossil fuel to solar fuel. This could mark a significant step toward a more sustainable and cleaner energy future.

Source: Rice University

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