Green Hydrogen: This is the world's most efficient photoelectrolyzer

A large perovskite optical panel for the record-breaking photoelectric analyzer

(Rinnovabili.it) – Green hydrogen production Using solar energy directly to “drive” water fractionation represents one of the most important advances in electrochemical technologies today. more than Optical analyzers However, the proposal so far is unstable due to material corrosion or ineffectiveness. The best results continue to be performed in small laboratory measurements.

This sector could be revolutionized New photoelectrochemical system (Photoelectrochemical-PEC) proposed by scientists at Ulsan National Institute of Science and Technology (UNIST), South Korea. The team comprehensively studied the challenges associated with live production Solar hydrogen, reselling the traditional PEC cell recipe. But above all, it combined all the desired characteristics in one product: high efficiency in converting solar energy into hydrogen, durability, and scalability.

Read also Solar hydrogen, perovskite gives record production efficiency

Photoelectrochemical technology for hydrogen production

In the photoelectrochemical water splitting process, hydrogen is generated using light and specialized semiconductors, similar to those used in photovoltaic power generation but immersed in an aqueous electrolyte. Sunlight is absorbed by semiconductors that act as the anode of the cell and split the H molecules₂Hey.

PEC reactors can be built in panels similar to photovoltaic panels e.g Electrode systems Or as systems grains of photocatalyst in suspension. The former is the most studied of all thanks to its similarity to photovoltaic technologies. the Challenges The biggest problems to solve at the moment are: Competencies, to be improved through greater light absorption and better surface catalysis; there DurationTo be enhanced by corrosion-resistant materials and protective surface coatings; the Production costs, to be reduced through materials and processes that are cheaper than current ones. As the professor explains Jae Seung Lee“, from the UNIST group,”Recently, a technique has been developed that solves the efficiency problem to some extent, but the results are obtained from a small laboratory apparatus. “For marketing, expansion is necessary to increase volume.”

UNIST photoelectrolyzer efficiency exceeds 10%

A key aspect of South Korea's transformation is the use of… Perovskites for their PVIt is a material known for its photovoltaic efficiency and is relatively cheap. On the other hand, as solar cells themselves have shown, most perovskites are particularly sensitive to environmental stress. Especially resistant to UV rays and humidity. On paper it is not the best choice for a material that will be used underwater.

the solution? The group produced more UV-stable perovskites, using… Formidinium comes as a cation in the molecule instead of traditional methylammonium. Therefore, the contact surface with water was complete Sealed with nickel foil To avoid corrosion.

Not only. This approach made it possible to increase the size of the photoelectric. These components typically have an area of ​​less than one square meter in research work and need to be enlarged about 10,000 times to reach a practical size for a commercial photoelectric analyzer. To scale perovskite photovoltaics, the team used… A “module-based design” that places small photoelectrodes of a certain sizeThen connect them together horizontally and vertically. In this way the device was achieved Solar hydrogen conversion efficiency is greater than 10% (minimum requirements for commercialization), which is the highest value ever achieved for a large area photovoltaic electrode. The results of this study were published on January 23 Nature's energy (English text).