IIT Guwahati Researchers Developing Cost-Efficient Materials To Generate Energy-Rich Hydrogen
With hydrogen being a clean, high-energy fuel that can be stored and used as needed, these cells are therefore considered the ‘Holy Grail’ to a carbon-free hydrogen economy.
The IIT Guwahati Research Team that developed cost-efficient materials to generate energy-rich hydrogen from water using Sunlight
Indian Institute of Technology Guwahati researchers is developing novel materials that can use sunlight to split water into hydrogen and oxygen. These materials are much cheaper than the ‘noble metals’ currently used and could lead to cost-effective solar-powered hydrogen generators.
The team at IIT Guwahati has developed non-noble metal catalysts that are as good as the expensive metals in splitting water in PEC cells.
The Important Benefits of this Research are:
- A combination of semiconductors that are impeded by their energy level mis-match for carrier transportation can use this approach as a model system
- Semiconductors with sluggish water oxidation kinetics can transform into materials with faster kinetics
- A model system to understand the basics of energy transfers among the semiconductors
When light falls on the anode of a PEC cell, negatively charged electrons and positively charged holes are generated (excitons). In the absence of a catalyst, the thermodynamic barrier will be very high to overcome, hence cannot split the water into hydrogen and oxygen.
In order to split water, the holes must be prevented from recombining with the electrons, or in other words they should efficiency separate and get transported to the surface of the semiconductor. In the ternary catalyst system developed by the IIT Guwahati team, the bismuth vanadate generates electrons and holes in response to sunlight.
Graphene siphons the holes away from the vanadate and transports them into the cobalt-tin LDH, thus preventing their recombination with the electrons. The holes and the electrons are now available to split the water into hydrogen and oxygen.
The photocurrent density of the ternary photoanode is three-fold higher than when using the bismuth vanadate by itself because of the extraction and transportation of the holes by graphene. These researchers believe that their findings would help us understand the mechanism of hetero-structured photoanodes and inspire the design of cheaper photoelectrode systems for improved water oxidations.
The researchers are now in the process of developing a prototype device to test their photoanode in practical PEC cells
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