More efficient extraction of hydrogen from water using microwaves

Scientists have developed a class of materials that can improve the extraction of hydrogen from water using microwave radiation. The new process will avoid carbon dioxide emissions resulting from hydrogen production.

This technological breakthrough is the work of a team from the Institute of Chemical Technology (ITQ), a joint research centre of the Polytechnic University of Valencia (UPV) and the Spanish National Research Council (CSIC), and the ITACA Institute of the UPV, all of these institutions in Spain.

The new process makes it possible to obtain hydrogen from renewable electrical energy, thereby avoiding carbon dioxide (CO2) emissions resulting from hydrogen production.

The research focuses on the significant improvement of green hydrogen production through redox cycles, in which the material takes and releases oxygen from water, separating it from oxygen in a stable manner. The developed process allows obtaining green hydrogen from renewable electrical energy due to the design and use of materials that have these redox properties and that respond to microwave radiation. The basis of the redox chemical cycle is the transfer of electrons between atoms of different elements in the presence of the induced electromagnetic field, which allows the electrification of the process.

Microwaves offer unique advantages in the electrification of a redox process, such as the provision of electrical energy without the need for contacts and the drastic reduction of the cycle temperature (from 1300 degrees Celsius to 400), which also reduces the complexity of the H2 production process and maximizes energy efficiency.

The main novelty of the work is the exhaustive study of the properties of the material that determine the performance of the process. The team, headed by Aitor Domínguez Saldaña from ITQ, has laid the foundations for the design of materials to adapt the production of oxygen and hydrogen, and adjust the energized state of the material depending on the desired application. In addition, it has been shown that it is possible to extract oxygen through a highly controlled, high-speed pulse process.

“The design of the cavities or chambers where we apply microwaves, as well as the control of the radiation process on these materials, is essential to take advantage of the unique advantages offered by microwave technology. In recent years, this technology has become established in numerous industrial applications due to its rapid scalability and high energy efficiency,” explains José Manuel Catalá, director of the ITACA Institute.

“During the research, a detailed study was made of the influence on hydrogen production of different dopants introduced into the matrix material (cerium oxide) with the aim of adjusting the interaction with microwave radiation and the properties of the resulting energized material. Subsequently, the hydrogen production capacity of this material and the mechanism that governs the process were studied, which will facilitate the future design of materials,” says José Manuel Serra, director of ITQ.

José Manuel Serra from ITQ and José Manuel Catalá from ITACA. (Photo: UPV)

The materials designed and used to improve hydrogen production have also been found to be strong and stable.

The study is titled “Enhanced Hydrogen Production in Microwave-Driven Water-Splitting Redox Cycles by Engineering Ceria Properties.” And it has been published in the academic journal Advanced Energy Materials. (Source: Polytechnic University of Valencia)