From carbon dioxide to methane - a new process

A new technique to convert CO2 to methane, to get a cleaner fossil fuel

From carbon dioxide to methane - a new process

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Read more on - Polity | Economy | Schemes | S&T | Environment

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• The story: Scientists have designed a photochemical method (Photocatalyst) to convert Carbon Dioxide (CO2)to Methane (CH4). A photochemical method is a chemical reaction initiated by the absorption of energy in the form of light.
• About methane: Methane is a gas found in small quantities in Earth's atmosphere, it is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms (CH4). But it is a powerful greenhouse gas, flammable, and used as a fuel worldwide.
• Process: A polymer has been designed to absorb visible light and catalyse the reaction which reduces CO2. Most catalysts contain toxic and expensive metal counterparts. Therefore scientists designed a metal-free porous organic polymer to overcome this drawback. The photochemical method of reducing CO2 uses solar light as a renewable source of energy.

1. There are many ways in which CO2 can be reduced, including photochemical, electrochemical, photoelectrochemical, photothermal, and so on.
2. The catalyst has a chemical called the Conjugated Microporous Polymer (CMP). It can uptake CO2 onto its surface due to its high CO2 intake capability at room temperature, converting it into methane as a value-added product. There are some requirements of a photo-catalyst to convert CO2 into value-added products, which rely upon - Light-harvesting property, Charge carrier (electron-hole pair) separation proficiency, and Presence of proper electronically aligned conduction band.

• Why do it: Methane can be one of the value-added products that can be the cleanest burning fossil fuel and can directly be used in fuel cells as a hydrogen carrier. It is a component of natural gas and has the potential to replace coal for electricity generation and furnishing flexible supply to reinforce intermittent renewable generators.
• How produced naturally: Methane is produced by the breakdown or decay of organic material and can be introduced into the atmosphere by either natural processes – such as the decay of plant material in wetlands, the seepage of gas from underground deposits or the digestion of food by cattle – or human activities – such as oil and gas production, rice farming or waste management. Methane is called marsh gas because it is found at the surface of marshy places
• Where is it used: It remains an important source of hydrogen and some organic chemicals, and reacts with steam at high temperatures to yield carbon monoxide and hydrogen; the latter is used in the manufacture of ammonia for fertilizers and explosives. Other valuable chemicals derived from methane include methanol, chloroform, carbon tetrachloride, and nitromethane. The incomplete combustion of methane yields carbon black, which is widely used as a reinforcing agent in rubber used for automobile tires.
• Powerful greenhouse gas: It is 84 times more potent than carbon but fortunately doesn’t last as long in the atmosphere before it breaks down. This makes it a critical target for reducing global warming more quickly while simultaneously working to reduce other greenhouse gases. But it is also responsible for creating ground-level ozone, a dangerous air pollutant.
• EXAM QUESTIONS: (1) Explain the renewed focus on methane as a greenhouse gas. (2) Explain the relative importance of climate mitigation strategies that focus on carbon dioxide versus those that focus on methane.

Read more on - Polity | Economy | Schemes | S&T | Environment

#methane #CO2 #greenhousegases #globalwarming #photocatalyst

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