A new study has shown how electrolysis (the process
of passing via water to separate hydrogen from oxygen in H2O) electricity could
generate hydrogen to store renewable energy. The solar panels would provide
extra electricity for electrolysis, producing hydrogen in the day. At night the
hydrogen generated would be combined with oxygen in the air to produce
electricity.
Chemical engineers at Stanford have modelled a
catalyst that could possibly enable producing large amounts of pure hydrogen by
means of electrolysis. Currently, pure hydrogen is derived from natural gas;
industrial hydrogen is mostly used for petroleum refining and fertilizer
production.
The research team intend to use electrolysis to
derive H2 from water and then use the process to conserve solar energy. However
to make this method industrially successful the research team must come up with
a cost-effective way.
Electrolysis is typically a simple experiment: place
two metal electrodes in water, and pass electricity through these electrodes
which makes them acts as catalysts to split water molecules into hydrogen and
oxygen gas. Platinum is a perfect catalyst for water-splitting process. However
to transform this method into an industrial process a low-cost electrode must
be used. Thus the aim of the research team is to make H2 without using precious
metals.
The team intends to go further than using
electrolysis to replace the existing demand for hydrogen. At present there is
no economically viable and large-scale method to store solar energy. This
research team thinks that electrolysis could convert gallons of water into
batteries for preserving solar energy. With the help of electricity,
electrolysis will break the chemical bonds that hold H2O together.
Breaking the chemical bonds of H20 will result in
the production of a hydrogen ion- a proton with no electron to create a
balance. A good H2 catalyst will provide the proton with a place to stick until
it can use an electron to form a hydrogen atom on the catalyst surface and then
combine with a neighbouring hydrogen atom to come off as H2. This method needs
a catalyst with the right stickiness because if the binding is not strong then
the ions wouldn’t stick and if the binding is too strong then the ions will
never be released.
Platinum is the best catalyst but is quite
expensive. In 2013, the Stanford engineers came across a type of molybdenum
sulphide, typically used for petrochemical processing, that had some of the
properties to act as a cheap yet effective alternative to platinum.
Petrochemical processing has certain similarities to
electrolysis as petroleum feed stocks consist of a substantial fraction of
heavy molecules. Petroleum refineries rely on catalytic reactions that use
hydrogen to break these heavy molecules into lighter molecules.
Electrolysis also involves breaking water molecules
or their chemical bonds. However, the researchers soon found a better way of
producing hydrogen from water.
Petroleum processing includes scrubbing sulphur out
of fuels in order to reduce acid rain, during which some of the sulphur atoms
get integrated into petroleum processing catalysts, thereby boosting the
activity of the catalysts. This scrubbing process armed the team with another
idea- if they added sulphur atoms to a good catalyst, it would function as a
better electrode for generating pure hydrogen.
The team decided to lace molybdenum phosphide with
sulphur atoms, which resulted in the production of a new catalyst molybdenum
phosphosulfide. This new catalyst was much more effective at creating hydrogen
than its precursor. This catalyst was much more resilient, which is an
extremely important property for a catalyst used in an industrial process. This
new catalyst is also stable and has the efficiency similar to that of platinum.
Now the team at Stanford is trying to further
improve the catalyst. The team has been relying on environment friendly
methods, but these methods have been developed on the basis of concepts
borrowed from petrochemical plants.
It is enthralling to see researchers link two
totally different areas of technology for such a noble purpose.
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A good set of information of Petrochemical industry..!!
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