A team of scientists from multiple institutions in India has pioneered a selenium-graphene-based catalyst, offering superior efficiency and durability compared to the typical platinum-based catalysts. This development has significant implications for contemporary energy technology such as fuel cells, largely utilized in hydrogen fuel-based cars. A catalyst that is not only proficient but also inexpensive is essential. Here, we provide an in-depth exploration of this new catalyst and its potential impact on the world of energy technology.
About Platinum-Based Catalysts
Fuel cells traditionally employ pricey components like platinum. While these metal-based technologies exhibit stellar performance in the initial cycles, they tend to degrade over time due to various factors.
The Selenium-Graphene Catalyst
By contrast, the selenium-graphene catalyst developed by the Indian scientists has shown promise. It has been demonstrated that graphene, when modified with minimal amounts of selenium atoms, can emulate platinum’s performance in a certain reaction, specifically, the oxygen reduction reaction. This reaction is integral to the function of a fuel cell and is typically catalyzed poorly by graphene. However, neither selenium nor graphene are effective when used independently; it is their combination that results in a highly efficient catalyst.
Poisoning and the New Catalyst
One commonplace variant of fuel cell, the methanol fuel cell, often suffers from a “poisoning” effect. This happens when methanol coats the negative electrode, causing it to become ineffective after a few cycles. This issue becomes particularly challenging when using expensive catalysts such as platinum. However, the newly created selenium-graphene catalyst exhibits a high tolerance for poisoning, effectively resisting the issue.
Catalyst Components: Selenium and Graphene
Selenium is a non-metallic element belonging to Group XVI of the periodic table. It shares many physical and chemical properties with sulfur and tellurium. With favourable photovoltaic and photoconductive properties, selenium finds abundant use in electronics.
Graphene, on the other hand, is a single layer of carbon atoms arranged in a hexagonal pattern. Considered the thinnest material in existence, it has impressive strength — about 200 times that of steel. It also shows excellent conduction of heat and electricity, along with notable light absorption abilities.
| Fact | Description |
|---|---|
| Selenium | Non-metallic element with photovoltaic and photoconductive properties. |
| Graphene | Single layer of carbon atoms, excellent conductor of heat and electricity. |
Fuel Cells: Functioning and Advantages
Fuel cells are electrochemical devices that convert chemical energy from reactants directly into electricity and heat. Gaseous fuels are continually fed to the anode (negative electrode), while an oxidant (commonly oxygen) is fed to the cathode (positive electrode). Electrochemical reactions occur at the electrodes, generating an electric current. Key advantages of fuel cell systems include high and scalable operating efficiency, zero or near-zero greenhouse emissions, and near-instant recharge ability compared to batteries.
Comparing Fuel Cells with Batteries and Heat Engines
The lifetime of a battery is limited due to various factors, including running out of chemical reactants and slow electrochemical reactions occurring even when not in use. However, fuel cells can supply electrical energy as long as fuel and an oxidant are supplied, with no “leakage” or corrosion when the system is inactive.
Heat engines, similar to fuel cells, convert chemical energy to electric energy but through multiple steps including combustion and mechanical energy conversion. They also require regular maintenance and have moving parts that can wear out over time. In contrast, fuel cells don’t have moving parts, making them more reliable, quieter, and less expensive to maintain. This reliability and efficiency make fuel cells an excellent alternative for a variety of applications, from automobiles to portable systems.