Iranian Researchers Set New Record in Green Hydrogen Production

This innovative achievement in the field of nanotechnology can revolutionize the process of green hydrogen production through photoelectrochemical water splitting (PEC-WS).

A team of Iranian researchers from the University of Isfahan, Amirkabir University of Technology - Mahshahr branch, a knowledge-based company, and the Institute of Fundamental Sciences used the inverse opal titanium oxide (IOT) nanostructure as an electron-transporting layer and scaffold for CsPbBr₃. This three-dimensional structure, known as a photonic crystal, enhances the absorption of photons in the perovskite layer by creating photonic gaps and increasing the effective path of light. Thus, more electron-holes are produced and the efficiency of the device is significantly increased.

Also, the high porous surface of TiO₂ provides conditions for faster collection and transfer of optical charges. To increase the durability of the electrode in an aqueous environment, the researchers applied a protective and conductive layer made of carbon black, graphite and recycled carbon toner. In addition to stabilizing the perovskite surface, this coating facilitated charge transfer and improved the device performance.

The experimental results showed that the photoanodes fabricated with this design achieved a photocurrent density of 7.28 mA/cm2 at a voltage of 1.23 VRHE. This performance was maintained in a long-term test for 10,000 seconds under continuous irradiation and in neutral conditions (pH = 7) without the use of a cocatalyst; an outstanding record among perovskite photoanodes.

Using a series of tests like UV-Vis absorption spectroscopy, line scan voltammetry, photoluminescence (PL) spectroscopy, and electrochemical impedance spectroscopy (EIS), the research team showed that the inverse opal structure not only enhanced the light absorption at the band edge, but also enhanced the optical charge separation.

This achievement demonstrates that the design of smart nanostructures and the use of conductive protective layers can overcome the traditional limitations of perovskites and make them a major option for the industrial production of green hydrogen.

In a relevant development in February, an international team of scientists led by Peking University had developed a new method of hydrogen production that eliminates direct carbon dioxide (CO2) emissions.

Published in the Science, the study offers an environmentally friendly and economically viable solution for the hydrogen industry.

Traditional methods of hydrogen production through ethanol reforming typically require high temperatures ranging from 300 to 600 degrees Celsius, consuming vast amounts of energy and generating significant CO2 emissions. The new process, however, uses a novel catalyst to produce hydrogen by reacting bioethanol -- derived from agricultural and forestry waste -- with water at a temperature of only 270 degrees Celsius.

This new bimetallic catalyst, developed by the research team over the past decade, overcomes the technical challenges of conventional ethanol reforming. It reduces the reaction temperature by precisely regulating the active sites, altering the reaction pathway entirely.

"Our research proposes a new pathway for efficient hydrogen production without CO2 emissions," said Ma Ding, a researcher at Peking University.

The study also reveals that the new method co-produces acetic acid, an organic chemical widely used in food preservation, manufacturing, and pharmaceuticals.

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