These panels look like your typical solar panels...

but in fact, instead of producing electricity, they make hydrogen.

When hydrogen generates electricity, it does not emit carbon dioxide.

For this reason, it's attracting attention around the world

as a new energy source that can replace fossil fuels.

The hydrogen being produced here is created using a new technology called artificial photosynthesis.

Artificial photosynthesis can provide an energy source
as long as there is sunlight.

The idea is to mimic photosynthesis, a process which plants have evolved over a long period of time.

Moreover, artificial photosynthesis is a technology of our dreams

that can turn carbon dioxide, one of the main causes of global warming, into a resource.

For decades, attempts have been made to commercialize artificial photosynthesis technology, but the development has been slow.

I've been told the idea was too difficult
that we should not pursue it.

But if we succeeded, the potential benefits
were immense, so we pushed ahead.

As the world attempts to combat global warming and make decarbonization efforts,

the technology that is attracting attention is...

artificial photosynthesis.

We get much of our energy by consuming large amounts of fossil fuels, such as oil and coal,

and emitting carbon dioxide, which causes global warming.

Artificial photosynthesis is one of the technologies that is said to tackle the issue of global warming.

How far has this technology come?

In today's Science View, we will take a look at the latest in artificial photosynthesis.

Professor Kazunari Domen of the University of Tokyo

has been Japan's leading researcher on artificial photosynthesis for more than 40 years.

In your research, how does
artificial photosynthesis work?

You add a bit of water onto this panel
and expose it to the sun.

Then, you get hydrogen from the panel.

That's all it takes to make hydrogen?

This ordinary-looking glass panel is what holds the secret to producing hydrogen.

This is how we conduct the experiment
inside the lab.

This is an experiment to expose light onto the panel.

Simply exposing light makes hydrogen?

Yes, we can make hydrogen indefinitely.

When light hits the panel, water is decomposed and hydrogen is created.

Each of these tiny bubbles is hydrogen.

Using this panel, hydrogen can be produced with just sunlight and water.

This is an experiment conducted in Ibaraki Prefecture to demonstrate the creation of hydrogen.

This Japanese national project took 10 years and more than 150 researchers including Domen to accomplish.

Using just sunlight and water from nature, they have succeeded in creating a large amount of hydrogen.

The byproduct of burning hydrogen is just water.

Artificial photosynthesis can endlessly provide
clean energy without emitting carbon dioxide.

Today, efforts to commercialize hydrogen energy are accelerating in Japan and around the world.

Hydrogen-powered vehicles such as cars, trains and ships as well as power generation systems are being developed at a rapid pace.

And, to create hydrogen, Domen was inspired...

by plants.

Plants absorb carbon dioxide from the air and efficiently produce organic matter.

Artificial photosynthesis is an approach to imitate this mechanism.

Domen's version of artificial photosynthesis is also inspired by the process

which plants have acquired over a long period of time.

However, Domen is not attempting to reproduce the process of photosynthesis entirely.

We only want to extract energy,
so we stop at the hydrogen process.

The process of photosynthesis in plants occurs in two stages.

The first stage is water splitting.

Water is broken down using sunlight.

During this time, water is broken down into oxygen and hydrogen.

The second stage is the production of organic matter.

Organic matter is created using carbon dioxide.

Domen's version of artificial photosynthesis produces hydrogen through the first stage of water splitting.

Artificial photosynthesis achieved by Domen uses a revolutionary technology.

We asked him to show us.

This is the room where photocatalysts are made.

Photocatalysts... what exactly are they?

Is this what we saw in the panel?

Yes. This is a sheet of photocatalyst
that was in the panel.

Photocatalytic powder is applied evenly on a glass.

If you touch it, the surface is grainy.

It feels powdery.

Yes, very fine powder is on the sheet.

When you touch the sheet, you get white powder on your finger.

They are photocatalysts, the substance that breaks down water.

The powder covering the surface of the panel was what was producing hydrogen.

A photocatalyst is a substance that absorbs light to promote chemical reactions.

Domen's photocatalyst is a compound that includes titanium.

This is a side view of the panel.

A sheet with water and photocatalysts is placed between two glass panels.

This is a micrograph of the cross-section.

The area outlined in red is the sheet and the white particles are the photocatalysts.

Hydrogen is generated from each of these particles.

This is how it works.

When light hits a photocatalyst, the electron inside it moves intensely.

The electron reacts with hydrogen ions in the water to form a hydrogen atom.

When two hydrogen atoms combine, they form hydrogen.

By utilizing the photocatalytic chemical reaction, a large amount of hydrogen could be produced.

Up until now, it had been hoped that renewable energy sources such as solar power could be used for hydrogen production.

However, this process requires using electricity that had been generated, posing the problem of low efficiency.

That is why, photocatalysts have attracted so much attention,

as they produce hydrogen directly from sunlight through a chemical reaction without the use of electricity.

The fundamental principle of photocatalysis was discovered roughly 50 years ago

by Japanese researchers Akira Fujishima and Kenichi Honda.

When a substance called titanium oxide connected to electrodes is exposed to light,

oxygen is produced on one electrode and hydrogen on the other.

Titanium oxide that absorbed the light, triggered a chemical reaction that broke down water into oxygen and hydrogen.

This phenomenon is called the "Honda-Fujishima Effect" after the scientists who had discovered it.

The discovery of photocatalysts sparked research on artificial photosynthesis around the world.

Since then, Japanese researchers have led the world through the development of high-performance photocatalysts.

One of them is Professor Domen.

He has developed over 100 kinds of photocatalysts during his 40 plus years of research,

investigating not only titanium oxide, but also the properties of other materials.

Among them, the one that produces the most hydrogen is the white powdery photocatalyst developed this time.

What makes your photocatalyst
different from others?

I have been using this photocatalyst
since I was a PhD student.

At the time the light utilization efficiency
was about 0.1%.

Now, it's nearly 100%.

However, there are still some issues to be solved.

Now, it only works with UV light.

To increase the efficiency, we need one
that can absorb visible light.

Sunlight is divided into three main types: Visible light, infrared, and ultraviolet light.

Currently, ultraviolet light, roughly 6% of the total, is the only energy being used for Domen's photocatalyst.

If visible light, which accounts for approximately 50% can be utilized,

it is expected to increase hydrogen production significantly.

Domen has already succeeded in developing photocatalysts that react to visible light.

By producing large amounts of hydrogen, there is high hopes for artificial photosynthesis to become widely available.

Artificial photosynthesis technology has not reached
practical application anywhere in the world.

I hope to take the lead
and to put it to practical use.

Artificial photosynthesis is a technology that aims

to solve energy and environmental problems by applying the power of plants.

At a laboratory of a major Japanese automobile manufacturer,

researchers are working on artificial photosynthesis from a different approach.

A successful demonstration of artificial photosynthesis was conducted at this lab in 2011.

This is the device that performed the first
artificial photosynthesis demonstration in 2011.

When light is directed on the silver device on the right, organic matter is produced.

The silver device contains water, carbon dioxide and a catalyst that causes a chemical reaction.

When light hits the catalyst, organic matter is produced, just like photosynthesis in plants.

This is Takeshi Morikawa who developed the device.

Carbon dioxide is burned organic matter.
I thought there must be a way

to turn it back to organic matter,
just as plants do.

Of the two stages of photosynthesis in plants,

Morikawa not only succeeded in the first stage of hydrogen production,

but also the second stage which is the production of organic matter.

Plants produce organic matter by taking in carbon dioxide from the air

to form leaves, stems, and their fruit, such as apples and tomatoes.

Its main component is starch.

In contrast, the artificial photosynthesis device developed by Morikawa

produces an organic substance called... formic acid.

Formic acid is a highly acidic substance produced by some ants in their bodies.

They defend themselves by spraying it onto their predators and enemies.

Morikawa believes that this highly acidic substance could play a role in solving the energy problem.

The reason is because it is a favorable substance for storing and transporting hydrogen.

The challenge with hydrogen is that it cannot be stored or transported at room temperature.

Currently, it is cooled to ultra-low temperatures, liquefied,

and transported by ship, which requires considerable energy and cost.

Formic acid, on the other hand, is a liquid that can be stored and transported at room temperature.

Moreover, hydrogen can be extracted when heated.

Given these advantages, Morikawa decided to produce formic acid through artificial photosynthesis.

With formic acid,
we can also extract hydrogen gas.

Electrical energy can also be extracted
as fuel for fuel cells.

Formic acid is highly valuable
as an energy carrier.

However, the first device developed in 2011 had an issue...

its low solar energy conversion efficiency.

At the time, the conversion efficiency was 0.04%.

Only a small fraction of the solar energy that hits the device was converted.

Since the conversion efficiency of plants is said to be 1% to 2%,

the performance was inferior to that of plants.

Morikawa and his team improved the device by developing a new catalyst,

and four years later, the energy conversion efficiency increased by more than 100 times.

In 2021, 10 years into its development, the device, which was originally compact,

had become quite large, measuring 1 meter on each side.

This is the latest artificial photosynthesis system.

The energy conversion efficiency is 10.5%, which achieved the world's highest performance as of 2021.

It produces the organic matter formic acid in a way that far exceeds

the energy conversion efficiency of plants through a different method from plants.

Here's how the latest equipment works.

A tank is filled with water, containing dissolved carbon dioxide.

Two types of catalysts are set in order to create a chemical reaction.

First, light hits the solar cells installed on the apparatus,

and water molecules are separated into oxygen and hydrogen ions.

The hydrogen ions react chemically with the carbon dioxide dissolved in the water to produce formic acid.

By using two catalysts, this method has achieved high efficiency.

We want to achieve a 20% efficiency
using formic acid or engineered carbon monoxide gas.

Morikawa and his team are working to further improve the efficiency of artificial photosynthesis to decarbonize the world.

Artificial photosynthesis produces not just hydrogen and formic acid.

This technology can also be applied to produce electricity from carbon dioxide.

This is Osaka Metropolitan University's Research Center for Artificial Photosynthesis.

Hello! I'm Michelle.
Thank you for having me.

I'm Yutaka Amao.
Thank you for coming.

Professor Yutaka Amao is developing an innovative system to supply energy for homes using artificial photosynthesis.

This house, still undergoing development, is powered by artificial photosynthesis.

The main feature is the panel.

What is being produced here is also formic acid.

The hydrogen and heat extracted from the formic acid provide enough electricity and hot water for one house.

We asked to see the panel that produces formic acid.

This is the panel that produces formic acid from carbon dioxide and water.

We use this panel to make formic acid.

All this is formic acid?
That's incredible.

The silver panel in the center produces formic acid.

When water and carbon dioxide are added to this panel, formic acid is quickly produced.

All the energy for the house is supplied using this formic acid.

Here is the mechanism of artificial photosynthesis for the house.

The formic acid produced by the panel is stored in a tank.

It is then converted into hydrogen and carbon dioxide.

Hydrogen is used as energy for electricity and heating water.

Meanwhile, carbon dioxide is collected and used as a source for making formic acid once again.

Carbon dioxide can be recycled to continue producing formic acid.

How much formic acid
does one house need in a day?

We estimate 20 kilograms per day.

The amount of formic acid that can be produced by this small panel is about 100 mL per day.

According to calculations, 200 of these panels would provide all that's needed to power one house for one day.

It does seem possible to line up
200 of these small panels on a roof.

Moreover, another device is being developed.

Inside, we see a large equipment.

This is another important device that is used inside the house Amao showed us earlier.

The equipment was developed by Shigeyuki Minami.

This is a home generator that uses
hydrogen made by artificial photosynthesis.

When hydrogen extracted from formic acid is added, it generates electricity.

Let's turn on the light.

The energy is generated by a hydrogen engine.

Meanwhile, Amao explains another device.

This device splits formic acid into a gas mixture
containing hydrogen and carbon dioxide.

This device contains formic acid.

When a catalyst is added, hydrogen and carbon dioxide are extracted through a chemical reaction.

As formic acid can be stored at room temperature

and easily be converted into hydrogen, it can be used to power homes.

Hydrogen, used as energy for electricity and hot water, turns into water when it is burned.

This water and carbon dioxide can be collected

and returned to the artificial photosynthesis panels to make formic acid again.

Energy can be produced with only water, carbon dioxide, and sunlight.

Our goal is to present the prototype
of the house at the Expo 2025 in Osaka.

We're working to complete it by 2050,
to meet the climate neutrality goal.

Amao envisions a future that can achieve decarbonization starting with homes utilizing artificial photosynthesis.

By making formic acid from
carbon dioxide and water,

our goal is to create homes
powered by artificial photosynthesis.

By bringing this technology to steel mills,
gas companies, and thermal power plants,

we could generate electricity by using
their carbon dioxide as a source.

I hope that this will move our society
toward carbon neutrality.

For Japan, which relies heavily on imports for its energy supply,

artificial photosynthesis could be the answer to help us achieve decarbonization.

As the world moves toward decarbonization, now is the perfect opportunity to accelerate this technology.

I look forward to hearing about new advancements in artificial photosynthesis,

that brings us a step closer to the day carbon dioxide could be used as a resource.