Development of reactor using Sunlight and Water

Development of reactor using Sunlight and Water

News: Scientists have, for the first time, developed a large-scale reactor which produces a substantial amount of hydrogen using sustainable sources like sunlight and water, which is a cost-effective and sustainable process.They have used an earth-abundant chemical called carbon nitrides as a catalyst for the purpose.This work is supported by the DST Nano Mission NATDP project.

Details:
• The team employed a low-cost organic semiconductor in carbon nitrides which can be prepared using cheaper precursors like urea and melamine at ease in a kilogram scale.When the sunlight falls on this semiconductor, electrons and holes are generated.The electrons reduced the protons to produce hydrogen, and holes are consumed by some chemical agents called sacrificial agents.
• If the holes are not consumed, then they will recombine with the electrons.The reactor is about 1 metre square, and the photocatalyst was coated in the form of panels where water flow is maintained.Upon natural sunlight irradiation, hydrogen production occurs and is quantified through gas chromatography.
• Hydrogen generated in this manner can be used in many forms like electricity generation through fuel cells in remote tribal areas, hydrogen stoves, and powering small gadgets, to mention a few.Eventually, they can power the transformers and e-vehicles, which are long-term research goals under progress.
• During his Independence Day speech, PM had announced the launch of a National Hydrogen Mission to accelerate plans to generate carbon-free fuel from renewables as he set a target of 2047 for the country to achieve self-reliance in energy.
• India has set a target of 450 GW of renewable energy by 2030. To achieve this, researchers are working towards renewable energy solutions that should be sustainable with a limited carbon footprint.

What is Hydrogen fuel?
• Hydrogen is the lightest and first element on the periodic table. Since the weight of hydrogen is less than air, it rises in the atmosphere and is therefore rarely found in its pure form, H2.
• At standard temperature and pressure, hydrogen is a nontoxic, nonmetallic, odorless, tasteless, colorless, and highly combustible diatomic gas.Hydrogen fuel is a zero-emission fuel burned with oxygen. It can be used in fuel cells or internal combustion engines. It is also used as a fuel for spacecraft propulsion.
• Hydrogen is the most abundant element in the universe. The sun and other stars are composed largely of hydrogen.Astronomers estimate that 90% of the atoms in the universe are hydrogen atoms. Hydrogen is a component of more compounds than any other element.Water is the most abundant compound of hydrogen found on earth.Molecular hydrogen is not available on Earth in convenient natural reservoirs. Most hydrogen on Earth is bonded to oxygen in water and to carbon in live or dead and/or fossilized biomass. It can be created by splitting water into hydrogen and oxygen.

Storage:
• Hydrogen can be stored physically as either a gas or a liquid.Storage of hydrogen as a gas typically requires high-pressure tanks.Storage of hydrogen as a liquid requires cryogenic temperatures because the boiling point of hydrogen at one atmosphere pressure is −252.8°C.
• Hydrogen can also be stored on the surfaces of solids (by adsorption) or within solids (by absorption).The only by-product or emission that results from the usage of hydrogen fuel is water — making the fuel 100 per cent clean.
• Hydrogen is considered an alternative fuel. It is due to its ability to power fuel cells in zero-emission electric vehicles, its potential for domestic production, and the fuel cell’s potential for high efficiency.
• In fact, a fuel cell coupled with an electric motor is two to three times more efficient than an internal combustion engine running on gasoline.Hydrogen can also serve as fuel for internal combustion engines.
• The energy in 2.2 pounds (1 kilogram) of hydrogen gas contains about the same as the energy in 1 gallon (6.2 pounds, 2.8 kilograms) of gasoline.

Way forward:
• Recently, the Finance Minister in the Union budget for 2020-21 formally announced the National HydrogenMission which aims for generation of hydrogen from green power resources.
• The Ministry of New and Renewable Energy (MNRE) has also disclosed that the draft regulations for NHM will be finalised by the end of this month and will thereafter proceed for approval of the Union Cabinet.
• One of the colossal challenges faced by the industry for using hydrogen commercially is the economic sustainability of extracting green or blue hydrogen.The technology used in production and use of hydrogen like carbon capture and storage (CCS) and hydrogen fuel cell technology are at nascent stage and is expensive which in turn increases the cost of production of hydrogen.
• The maintenance costs for fuel cells post-completion of a plant can be costly, like in South Korea.
• The commercial usage of hydrogen as a fuel and in industries requires mammoth investment in R&D of such technology and infrastructure for production, storage, transportation and demand creation for hydrogen.