With rising use of fossil fuels and increasing greenhouse gas emissions, the world needs clean new energy sources. Atta-ur-Rahman Prize winner Mirabbos Hojamberdiev studies how to produce hydrogen from water by using inorganic crystals under visible light
VIENNA - Mirabbos Hojamberdiev, a chemist from Tashkent, Uzbekistan, is the recipient of the 2015 Atta-ur-Rahman Prize in chemistry. He receives the prize for his contributions to inorganic chemistry: he aims at growing inorganic crystals that are able to generate hydrogen from water molecules, once they are hit by solar light.
The announcement was made Wednesday, 18 Nov. during the opening ceremony of The World Academy of Sciences (TWAS) 26th General Meeting, held this year in Vienna, Austria from 18-21 Nov. The prize acknowledges talented young chemists who live and work in scientifically lagging countries. The prize is provided by Pakistani TWAS Fellow Atta-ur-Rahman, a leading scholar in the field of organic chemistry and a globally influential advocate of science education.
"The TWAS Atta-ur-Rahman prize is an unique recognition in the world for young scientists coming from developing countries," Hojamberdiev says. "Being an important international prize, it will give me even more motivation and encouragement to my work, and it will be a matter of pride for my country."
Mirabbos Hojamberdiev is a senior researcher in the department of natural and mathematic sciences, Turin Polytechnic University in Tashkent, Uzbekistan. As an undergraduate, he developed an interest in environmental issues: he focused, in particular, on water contamination, which is a serious problem in Uzbekistan. However, in a few years he developed also a deep interest also in materials science, and he thought he could merge the two fields to achieve valuable results.
He earned his master's of science (2001) and his PhD (2005) in materials science from Tashkent Institute of Chemical Technology, Uzbekistan. In 2006, he gained a diploma in inorganic environmental materials from Tokyo Institute of Technology in Japan, where he is now a visiting researcher until March 2016. His scientific interests include nanomaterials,?clay minerals, environmental materials, hydrothermal synthesis, flux crystal growth and utilization of industrial wastes.
Hojamberdiev has been working for over 12 years on different research projects related to the development of novel advanced materials. During these years, through international collaborations with groups in China, Japan, Peru, Germany, US, Malaysia, Egypt, Brazil, Thailand, and Argentina, he has gained broad experience to use methods and equipments which are very important in materials characterization, such as scanning electron microscopy, transmission electron microscopy, atomic force microscopy?and Raman spectroscopy. He is now sharing this expertise with colleagues in Uzbekistan.
With TWAS, he is the recipient of a travel grant to follow TWAS's Science and Diplomacy Workshop on "Innovative Energy Policies for Sustainable Future" (2013), and a participant in the TWAS Visiting Expert Programme? (2015). In 2011 he was granted with the TWAS/UNESCO Associateship and in 2010 he was the winner of the TWAS Prize for Young Scientists in Developing Countries (chemistry).
Currently, his major interest is photocatalytic water splitting using solar energy: the generation of renewable clean energy in the form of gaseous hydrogen (H2) by using visible light. "Using sustainable energy sources such as solar, wind, hydro, or biomass to reduce greenhouse gas emissions and non-renewable resource exploitation is becoming mandatory," Hojamberdiev says. "Hydrogen is a clean source of energy ... but we need to find the way to produce it routinely and at little costs."
Today, global hydrogen production (more than 50 million tons per year) depends on 48% natural gas, 30% oil, 18% coal and only 4% water electrolysis (known also as water splitting). One way to achieve its production in sustainable way would be through photocatalytic water splitting, a process that generates free hydrogen and oxygen with the aid of solar light.
Using his knowledge of materials science and his expertise in inorganic chemistry, Hojamberdiev started growing inorganic crystals in laboratory. The idea was to use crystals as photocatalysts, that upon solar light activation are able to split water molecules apart.
In preliminary tests, he prepared aqueous and non-aqueous solutions of salts using common salts such as sodium or potassium chloride and others, and upon application of controlled temperature and pressure conditions he succeeded in growing small inorganic crystals. Placing these crystals in water under visibile light (always under controlled temperature/pressure conditions) would trigger the production of free hydrogen in the system.
Unfortunately, the crystals growing this way do not produce hydrogen very efficiently, because of structural defects they contain. By introducing a modification to the whole process, using so-called "ammonia-assisted direct flux growth", Hojamberdiev succeeded in precisely controlling morphology, size, and dimension of photocatalytic inorganic crystals. He was able to grow purer structures that split water molecules eight times more efficiently than other methods.
The inorganic photocatalysts that Hojamberdiev uses now as starters for hydrogen generation belong to the so-called family of (Oxy)nitrides. The family includes titanium, zirconium, niobium and tantalium. They exhibit high photocatalytic activity for water splitting, and have several advantages: they are more stable than organic materials, they can be recycled, are cheap, non-toxic and abundant. In addition, they are only active with solar light, which gives Uzbekistan a priviledged position. Uzbekistan, in fact, experiences an average of 300 sunny days per year.
But there is more to that. The same procedure can be used to purify polluted water. When placed in a contamined water solution and hit by visible light, the crystals break complex molecules into simple ones, suggesting that they might be used as remediation tools. "The whole system is in its infancy now: we have chosen some materials and tested their performance. Today we are working to make the process even more efficient and feasible for scaling-up," the scientist notes. His future plans are to establish collaborations with industries to set up large-scale pilot tests.
And there is hope to that: Uzbekistan is building new solar energy institutes, and the Asian Development Bank (ABD) is supporting the project by investing in Uzbekistan. In 2014, in fact, ADB provided a loan of $300 million to support energy-efficient power generation that will meet rising electricity demand in this country.
About Atta-ur-Rahman Prize
The Atta-ur-Rahman Prize was established in 2012 by Pakistani TWAS Fellow Atta-ur-Rahman, a leading scientist and scholar in the field of organic chemistry, renowned for his research in areas related to natural product chemistry. The award brings a prize of USD5,000, and is annually given to a talented chemist who lives and works in any of the 81 scientifically lagging countries and who is under the age of 40.
Winners are invited to attend the TWAS General Meeting and give a public lecture on their work. Each TWAS Regional Office is asked to present one candidate from their region, and the final selection is made by professor Atta-ur-Raman himself. Previous winners are: Mohamed Fawzy Ramadan Hassanien, Egypt (2014); Mohammad Abdul Hasnat, Bangladesh (2013); and Shamsun Nahar Khan, Bangladesh (2012).