Multi-institutional team builds leaf-like catalytic structures for solar-powered production of green hydrogen and ammonia
A multi-institutional team from IIT Mandi, IIT Delhi and Yogi Vemana University has replicated the formation of a low-cost inorganic catalyst leaf to enable light-induced production of green hydrogen and ammonia.
As a result of their recent work, a team led by Venkata Krishnan, Associate Professor, School of Basic Sciences, IIT Mandi, published an article in the prestigious Journal of Materials Chemistry. The article is co-authored by his research scholar Ashish Kumar. From IIT Mandi. Other writers include his collaborators Shaswata Bhattacharya and Manish Kumar of IIT Delhi, and MV Shankar and Navkoteshwar Rao, professors at Yogi Vemana University in Andhra Pradesh.
In early 1912, a pioneer Armenian chemist, Giacomo Siamese, in his research paper entitled ‘The Photochemistry of the Future’, challenged the scientists of his time to imagine creating chemicals using sunlight, such as plant photosynthesis. In the 1970s, researchers showed the possibility of collecting the sun’s light energy through the use of photosynthetic materials, known as the photocatalysis era. Since then, many photocatalysts have been discovered to bring about light-capable reactions for a variety of purposes, and research into many aspects of photochemical synthesis has been under way to discover new photocatalysts and improve existing ones.
Hydrogen is a green energy source and ammonia is the backbone of the fertilizer industry. Both hydrogen and ammonia are being produced through a process that consumes a lot of energy in the form of heat and also emits greenhouse gases. The use of photocatalysis in the production of these two chemicals not only saves energy and cost but also has significant environmental benefits.
Researchers have identified the major barriers to photocatalysis – the need for catalytically active sites to effectively use sunlight to carry out poor light absorption, photoegenerated charge recombination, and chemical reactions. They improved the properties of the low-cost photocatalyst, calcium titanate, through a method called ‘defect engineering’, and demonstrated its effectiveness in producing green hydrogen and ammonia in two light-driven reactions. In particular, error engineering was performed by incorporating oxygen vacuums in a controlled manner. These oxygen vacuoles act as catalytically active sites to enhance surface responses and thereby increase photocatalytic performance.
Scientists have studied the structural and morphological stability of defective photocatalysts and have shown that their photocatalysts have shown excellent structural stability because the defects of engineered oxygen vacuum were well captured after the recycling study. They use catalysts to make ammonia from hydrogen and nitrogen from water, and use sunlight as an activator at ambient temperature and pressure.
Venkata Krishnan hopes that their work will provide a direction for the smart design of error-engineered three-dimensional photocatalysts for green energy and environment-based applications.