Researchers from the Magnetism and Nanotechnology (NanoMag) group of the University of Santiago de Compostela have found that hydrogen respectful to the environment can be produced through the “photoproduction” of water with solar energy. This discovery will increase the performance in the processes to obtain hydrogen from water.
The Magnetism and Nanotechnology ( NanoMag ) researchers’ group of the University of Santiago de Compostela (USC ) Yasser Attia, David Buceta , M. Carmen Blanco and Arturo López Quintela say there is a Photocatalytic “extraordinary activity” to produce hydrogen with clusters of silver and water with performance reaching up to 10% .
Hydrogen, perfect fuel
Researchers believe that , compared to solid fuels, hydrogen is the perfect fuel , both for its energy content and its zero environmental impact, since the only by-product resulting from combustion is water.
However, one of the major problems impeding the use of hydrogen as a fuel to market is its production process because it involves significant energy consumption. The catalysts that are present are either not economically viable or have very low yields of about 0.1 %, according to the researchers from USC.
Sub- nanometric metal
The results achieved by NanoMag were used to “clearly demonstrate that the groups of sub- nanometric metals in zero oxidation state contain only a very small amount of atoms (less than 50-100 atoms), behave as semiconductors and can absorb a photon through photogeneration with the consequent creation of an electron and a hole.”
The presence of species that capture this gap (known as species of sacrifice or oxidizable species -hole scavengers) or photoelectrons generated in the cluster can be transferred very efficiently to the metal in which they are deposited, given their extremely small size for a semiconductor. Through the metal (used in the experiments in the form of small nanoparticles) , the generated photoelectrons are capable of reducing the production of water hydrogen gas with high efficiency rates.
Photocatalytic hydrogen production was achieved using silver clusters that absorb mainly ultraviolet light, so only a small part of sunlight can be used. However, researchers have also found that by varying the size of the clusters it is possible to tune the wavelength of absorption, which “could allow to select groups of different sizes, so that they could use all of the sunlight much more efficiently” .
This is one of the main goals of the research where the NANOMAG USC group is currently involved in collaboration with other research centers in Europe, in order to overcome current problems and succeed in producing hydrogen cleanly and efficiently with solar cells.
The work of this team that is included under the USC’s Research Institute of Technology has also the collaboration of Professors Giampaolo Barone, University of Palermo and Mona Mohamed from Cairo University and has been recently published in the prestigious journal Journal of the American Chemical Society.
Source : Xornal da USC