“Basically,
we combined the best of both worlds. We start with a chemically stable, low
cost metal Oxide, add a really good but simple silicon-based thin film Solar
cell, and -- voilà -- we've just created a cost-effective, highly stable, and
highly efficient Solar fuel device”
Prof. Dr. Roel van de Krol, head of the HZB
Institute for Solar Fuels on the development of Artificial Photosynthesis using
Bismuth
Vanadate (BiVO4) coated Solar Panels
Photosynthesis is a process by which plants take Solar
Radiation and use it to convert Carbon diOxide and Water into Glucose, with
Oxygen as the by-product. Earlier in March 2013, Dr Michael Adams of the
University of Georgia’s Bio-Energy Systems Research Institute and his team were
able to successfully bio-engineer a bacterium, Pyrococcusfuriosus, to convert atmospheric CO2 into
Bio-fuel as stated in my blog article
entitled “Pyrococcusfuriosus
Bacterium Bio-engineered by University of Georgia’s to convert Carbon DiOxide
to Bio-fuel - Carbon Sequestering profitable
Hunger Games Catching Fire”.
Now we’re getting close with the recent development
of a Solar System that can use Solar Radiation to convert Water into Hydrogen
and Oxygen in a more efficient form of Electrolysis called Artificial Photosynthesis
as described in “The
best of two worlds: Solar hydrogen production breakthrough”, published Jul 29, 2013, Phys.org.
It’s pretty much the same as using Solar Panels to
split water into Hydrogen and Oxygen. Under those conditions, the water chose
is usually deionized water to reduce the formation of salts at the Anode (+)
and Cathode (-), usually inert Platinum Electrodes. It differs in this case as
the Anode and Cathode are instead on the surface of the Solar Panel. Also
instead of being made of thin plates of platinum, the Anode is made of Bismuth Vanadate
(BiVO4) coated with a protective coating of Cobalt Phosphate (CoPO4)
catalyst with a Platinum wire Cathode.
A
Graphite bridge is used to connect the Anode to the standard Solar Panel, which
is made of the usual doped Silicon (Si) coated with protective Glass. The
circuit is completed as shown below:
This
improves the electrolysis process, as the Solar Panel is now in direct contact
with the water instead of generating Electricity solely for the purpose of
splitting Water. The Cobalt Phosphate (CoPO4)
catalyst, which is sprayed onto the 300nm thick layer of Bismuth
Vanadate (BiVO4), helps to improve the efficiency of the production
of Oxygen at the Anode and protect the Solar Panel from corrosion, as it’s
sprayed on as a very thin Nano-particulate layer.
In essence, this makes the Anode a Nano-Electrode.
Wolfram Atoms or basically Nano-particles of Tungsten (W), being as Wolfram is
an older name for the Transition Metal and the explanation for it’s symbol W as
noted in Tungsten
or Wolfram Facts, By Anne Marie Helmenstine, Ph.D, viewed August 27 2013, About.com.
Nano-particles of Tungsten (W) Atoms are added to
make the Bismuth Vanadate (BiVO4) more reactive and reduce electron-proton
charge recombination and more efficient flow of free electrons, to quote
Professor Dr. Roel van de Krol: “What's important is that we distribute
these wolfram atoms in a very specific way so that they can set up an internal
electric field, which helps to prevent recombination”.
This
impressive process only uses 5% of the total Electricity generates and can
reach as high as 9%, leaving the other 95% for use to power the Electrical
system of the house. Thanks to the new design using an Anode
made of Bismuth Vanadate (BiVO4) coated with Cobalt Phosphate (CoPO4)
catalyst.
In
addition to this, 80% of the incident photons contribute to the Electricity
generated, a record for any Oxide, to quote Professor Dr. Roel van de Krol: “We
don't really understand quite yet why Bismuth Vanadate works so much better
than other metal Oxides. We found that more than 80 percent of the incident
photons contribute to the current, an unexpectedly high value that sets a new
record for metal Oxides”.
Thus
the Hydrogen produced at the Platinum Cathode can be stored and used in
Hydrogen Fuel Cells to provide power at night, in a sense paving the way to
eliminating batteries to store Electricity even as it powers the house. This as
the 5%-9% of Electrical Energy stored as Hydrogen Gas can be reused at night or
on cloud days, for which the problem of storing Hydrogen Gas becomes a problem.
To
give you an idea what this means in practical terms, 600W per square meter,
which is the average Power generated by Solar Panels in Germany’s translates to
60 KW of power generated from 100 square meter Solar Panels of which 5% is 3 KW
of power, enough to split hydrogen which when stored can be accessed during the
night or on very cloudy day via a Hydrogen Fuel cell or used directly for
Heating and Cooking.
Ironically,
scientists here in Jamaica at the University of Technology and the University
of the West Indies are working on, but with the intention to replace imported
LPG (Liquid Petroleum Gas) Cooking Cylinders as explained in my
blog article
entitled “UTECH
partners with GOJ and UWI to develope Hydrogen Cooking Gas Cylinders - EU
Funded 3 Year Project is Chasing Mavericks to push Jamaica into the
Hydrogen-Electron Economy”.
Most
likely the platinum Electrodes may be a fine gauze mesh of platinum instead of
the thin sheets normally used so as to allow the sunlight to pass through. Or even
better, it may be the same plates of platinum but instead sprayed on a Glass
plate, making this still a very expensive Electrolysis process.
Possibly
this can be replaced with a Glass plate with sprayed on Nano-particles of
Platinum or Silver to create a Glass Electrode. This would allow the Solar Panels
to thus function by being place flat like regular Solar Panels and allowing the
water to flow over its surface via gravity fed water source with the Hydrogen
formed being collected.
Such
a process is truly a breakthrough, as it makes the production of Hydrogen Gas
for use in Fuel Cells or other forms of Energy Storage very efficient using a
minimum of Electricity generated and improved Electrodes. Thus it is with in
mind that I’d recommend collaboration between Professor Dr. Roel van de Krol of
the HZB Institute for Solar Fuels as well as the lecturers at the University of
the West Indies and the University of Technology.
