Dr. Maibelin Rosales, a researcher at the Advanced Mining Technology Center (AMTC) of the University of Chile, proposes the advantages of obtaining hydrogen by harnessing direct sunlight and nanomaterials designed from copper oxide and tin oxide.
Chile was the destination chosen by Maibelin Rosales to pursue her doctoral studies in Materials Science, a country that the young researcher highlights as a benchmark in research and technology at the Latin American level.
The chemical engineer left her position at the Venezuelan Institute for Scientific Research to begin her advanced training in 2015 at the Faculty of Physical and Mathematical Sciences of the University of Chile, where she completed her doctoral studies in 2019. During this period, she also joined as a researcher at the Advanced Mining Technology Center (AMTC) of the same institution, where she is currently working on a project that won the Fondecyt Postdoctoral Competition 2022. The project focuses on the production of green hydrogen through the design of nanomaterials.
The innovative proposal suggests the possibility of producing hydrogen through photocatalysis, i.e., by the reaction of these nanomaterials that, when exposed to sunlight, can break down the H2O molecule to produce hydrogen.
Dr. Rosales emphasizes that “the photocatalytic generation of green hydrogen by watersplitting emerges as a promising alternative to electrolysis, as it does not require an external source of electrical energy to separate the water molecule into hydrogen and oxygen. In this case, solar radiation directly acts as the energy source on the nanomaterial, and it is capable of photogenerating the necessary electric charges to carry out the separation.”
The innovative proposal suggests the possibility of producing hydrogen through photocatalysis, that is, through the reaction of these nanomaterials that, when exposed to sunlight, can break down the H2O molecule to produce hydrogen.
One of the advantages of this system lies in the fact that “by requiring only sunlight and a semiconductor nanomaterial, the use of expensive and robust equipment or the integration with photovoltaic panels to obtain the required energy is avoided,” explains the now Doctor in Materials Science.
Currently, she points out, “electrolysis, being a more mature technology, leads in this production compared to photocatalysis, which is an emerging technology still in the development phase. This means that the industrial scaling of photocatalysis may involve higher initial costs than electrolysis, but with the potential for reduction as the technology advances and scales.”
The Magic of Nanomaterials
The search for semiconductor materials for hydrogen photoproduction, capable of breaking the water molecule, led the researcher from the University of Chile to work with two materials: copper oxide and tin dioxide. “The first choice was that they be materials capable of performing this photocatalytic reaction, but also that they can be used to take advantage of the broader range of the solar spectrum,” explains Maibelin Rosales, who mentions that another criterion was to use economical materials to work from the beginning on less costly production processes. They also considered the photothermal capacity, that is, the ability to absorb solar energy to generate heat in the water, which helps accelerate the photocatalytic reaction.
The chemical engineer thus began experimentation with different designs on a nanoscale, with sizes almost 100,000 times smaller than the diameter of a human hair and about 100 times smaller than the Coronavirus. “One of the most impressive aspects of these materials is that most of their properties are enhanced when brought into the nano-world, but, in addition, when we change their shapes, their properties also vary dramatically,” she explains. Another innovative point, she adds, “is that by properly designing the different forms of these nanomaterials, we also change their opto-electronic properties and can give them a photothermal property. This means that under sunlight, they can generate heat autonomously, which increases the water temperature and, therefore, improves the reaction rate for hydrogen generation.”
Spheres, tubes, leaf-like sheets, and even flowers have been some of the nanometric shapes designed by the researcher from the University of Chile. “This manipulation of their shapes has allowed me to adjust many of their properties and make them suitable for absorbing energy across a broad range of the solar spectrum, making many of them efficiently usable under solar irradiation. In addition, several of them have also exhibited the mentioned photothermal capacity, which is advantageous in accelerating the reaction to generate H2.”
Currently, Dr. Maybelline Rosales is examining these nanomaterials designed in Chile at specialized laboratories for field emission scanning electron microscopy at McGill University in Montreal. In December, she will return to Chile to advance to a new stage of tests for those structures that were successfully designed and showed greater advantages for hydrogen production.
A green future for hydrogen in Chile
According to the Ministry of Energy, Chile could reduce its CO2 emissions by 20% by 2050 thanks to the deployment of the green hydrogen industry. Its production through electrolysis is currently mainly supported by the use of electricity generated from sources such as photovoltaic solar energy, with costs ranging between $3 and $7.5 USD/KgH2. Nevertheless, although it is not yet commercially competitive compared to hydrogen obtained from fossil fuels (which does not exceed $3.2 USD/KgH2), it is expected that in Chile this cost will decrease to $1.4 USD/KgH2 by 2030.
These projections would position Chile not only as the most economical H2V producer worldwide but also as one of the main hydrogen exporters by 2040. In this direction, progress in scientific and technological research and development for the photocatalytic production of green hydrogen from nanomaterials could mean a revolution in the industry. “Its advantages in terms of simpler and more economical processes compared to electrolysis provide a green alternative, environmentally friendly, and with greater economic viability for production,” says Dr. Maybelline Rosales.
Close to 95% of the current commercial hydrogen production comes from a process that consumes a lot of energy and is accompanied by the release of large amounts of CO2. In this sense, the green hydrogen economy goes hand in hand with the energy transition that allows us to move towards the goal of carbon neutrality by 2050.
For this reason, the researcher from the University of Chile points out that, “considering that northern Chile has one of the highest solar radiation potentials worldwide,’ it is impossible not to work towards scientific and technological developments that allow us to take advantage of this privileged geographical position. Keeping this in mind, I am confident that the synergy between nanotechnology and solar technology will make it possible for this type of lower-cost and easily implementable innovation to not only help achieve the decarbonization goal but also lead the list of countries with the highest hydrogen production from solar energy”.
SOURCE: LA TERCERA
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