This presentation shows the concept of artificial photosynthesis and the current development and research in it.

1. Made by-
Rishabh Dubey
17036556048
Bsc(H) Botany 3rd Year

2. The basics!!!
• Chemical process that bio-mimic the natural process
of photosynthesis.
• Convert sunlight, H2O, and CO2 into carbohydrates and O2.
• Photocatalytic water splitting.
• Light-driven carbon dioxide reduction.

3. A bit of history….
• First anticipated by the Italian chemist Giacomo
Ciamician during 1912.
• Proposed a switch from the use of fossil fuels to
radiant energy provided by the sun and captured
by technical photochemistry devices.
• Visible light water splitting with a one piece
multijunction semiconductor cell (vs. UV light
with titanium dioxide semiconductors) was first
demonstrated and patented by William Ayers at
Energy Conversion Devices during 1983.
• During 2008, Andrew B. Bocarsly reported the
direct conversion of carbon dioxide and water to
methanol using solar energy in a very efficient
photochemical cell.
• During 2011, Daniel Nocera and his research
team announced the creation of the first practical
artificial leaf.

4. A photosensitizer (P)
A water oxidation catalyst (D)
A hydrogen evolving catalyst (A)
Electrons flow from D to A when catalysis occurs.
A
P
D
The Assembly……

5. The 4 basic steps in Artificial
Photosynthesis
1. Light Harvesting
• Multiple absorbers with complementary absorption profiles as light harvesters.
• Light harvesters transfer their excitation energy to an artificial reaction centre.
• Light-harvesting systems could be made from organic molecules (eg - silicon solar cells)
2. Photoinduced charge separation- is the process of an electron in an atom or molecule,
being excited to a higher energy level by the absorption of a photon and then leaving the
atom or molecule to a nearby electron acceptor.
3. Splitting of Water-The positive charges obtained from the charge separation are used to
oxidise water and split the hydrogen from the oxygen.
Done via water oxidation electro catalyst.
4. Fuel Production-The easiest way hydrogen gas (H2 gas) can be made is on the surface of
noble metals such as platinum.

6. Lab setup of Artificial Photosynthesis

7. A schematic description that shows the principles of artificial photosynthesis (Artificial Leaf). Whole process can be
divided into four elements; (1) light-harvesting, (2) reaction center, (3) oxidation catalyst, and (4) reduction
catalyst.

8. The difference…….

11. Natural Photosynthesis Artificial photosynthesis
1- HYDROGEN CATALYSTS Hydrogenases Dirhodium photocatalysts
and cobalt catalysts
2- WATER-OXIDIZING CATALYSTS OEC within
PS II
Ruthenium(IV) oxide (RuO2),
Iridium(IV) oxide (IrO2), Cobalt
oxides etc
3- PHOTO-SENSITIZERS Pigments (mainly chlorophyll) Tris(bipyridine)
ruthenium(II),
Metal-free organic complexes like
Eosin Y
4- CARBON DIOXIDE REDUCTION
CATALYSTS
RuBisco (Calvin Cycle) Transition metal polyphosphine

13. ADVANTAGES DRAWBACKS
• Solar energy can be immediately converted and
stored.
• By-products of these reactions are
environmentally friendly.
• Artificially photosynthesized fuel would be
a carbon-neutral source of energy
• Materials used for artificial photosynthesis often
corrode in water
• Hydrogen catalysts are very sensitive to oxygen
• Raw materials (for example noble metals for
catalysis) and manufacturing methods (for
example for multi-layer artificial leaves) are still
too costly.

14. Applications……..

15. Artificial leaf
• A silicon solar cell with different catalytic
materials bonded onto its two sides.
• Needs no external wires or control circuits
to operate.
• Simply placed in a container of water and
exposed to sunlight, it quickly begins to
generate streams of bubbles: oxygen
bubbles from one side and hydrogen
bubbles from the other.
• If placed in a container that has a barrier to
separate the two sides, the two streams of
bubbles can be collected and stored, and
used later to deliver power: for example,
by feeding them into a fuel cell that
combines them once again into water
while delivering an electric current.

18. Bionic leaf
• The Bionic Leaf is a system that uses solar
energy to split water molecules and hydrogen-
eating bacteria to produce liquid fuels.
• It is made of a thin sheet
of semiconducting silicon with
different catalytic materials bonded to its two
sides.
• A layer of bacteria with a cobalt-based catalyst is
bonded to the silicon, which splits water
into oxygen and hydrogen.
• The bionic leaf's artificial photosynthesis is two
times better than natural photosynthesis.
• The water-splitting electrodes produce hydrogen,
which is consumed by the bacteria to synthesize
biomass and fuels or chemical products.

19.  Agriculture
The soil bacterium Xanthobacter autotrophicus was used to consume hydrogen generated
by the water-splitting reaction and take nitrogen from the atmosphere to
produce ammonia and phosphorus. These products can be used as fertilizers. In
greenhouse experiments at the Arnold Arboretum, growing radishes with X.
autorophicus resulted in an increase in size without added fertilizer. The bacteria can
secrete ammonia directly, which can appeal to companies that convert
atmospheric nitrogen into ammonia, which relies heavily on fossil fuels.
 Bioplastics
Researchers were able to expand the portfolio of the system able to
produce isobutanol and isopentanol. Sinskey's lab at MIT engineered a Ralstonia strain to
use in the bionic leaf to generate polyhydroxybutyrate PHB, a bio-plastic precursor.
 Atmosphere
Carbon dioxide, a greenhouse gas, traps heat in the atmosphere. The bionic leaf can
potentially be used to consume carbon dioxide. The bionic leaf can eliminate 180 grams of
carbon dioxide out of 230,000 litres of air for each kilowatt hour of energy it consumes.
Applications….

21. A failed success……

23.  Plastic Precursors can be Formulated via Artificial Photosynthesis
At Rutgers University, scientists are working on methods to produce methylglyoxal and 2,3-furandiol directly
from artificial photosynthesis. These two chemicals are important precursors used in the production of
plastics, adhesives, and pharmaceuticals, and they are otherwise produced via environmentally dirty
processes that require the use of petroleum. And, in this case, the catalyst doesn’t have to be gold. The
methodology involves five distinct catalysts made primarily from nickel and phosphorus. By varying the conditions of
the method and swapping catalysts, the chemical can be built “string together” a greater or lesser number of carbon
atoms into polymers, to build different useful chemicals.
The Rutgers scientists have formed a commercial enterprise, Renew CO2, in an attempt to commercialize their
discovery.
The lesser known fact….

24. • https://phys.org/news/2019-05-artificial-
photosynthesis-carbon-dioxide-liquefiable.html
• https://pubs.acs.org/doi/pdf/10.1021/acs.accou
nts.9b00380
• https://www.sciencedaily.com/releases/2019/11/
191104130454.htm
• https://www.photonics.com/Articles/Artificial_Ph
otosynthesis_Could_Help_Limit_Carbon/a64323
• https://royalsocietypublishing.org/doi/full/10.109
8/rsfs.2015.0014?url_ver=Z39.88-
2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr
_pub%3Dpubmed&
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