New Catalyst Boosts Energy-Efficient Hydrogen Production

Hydrogen is a clean and abundant source of energy that can reduce carbon emissions and combat climate change. However, producing hydrogen from water requires a lot of energy and expensive catalysts. Scientists in India have discovered a new catalyst that can lower the energy demand and cost of hydrogen production by using urea as an additive.

Introduction

Hydrogen is widely regarded as a promising alternative to fossil fuels, as it can provide clean and renewable energy for various applications, such as transportation and industry. Hydrogen has the highest energy content per unit mass among all fuels, and when used in fuel cells or combustion engines, it only emits water vapour, thus avoiding air pollution and greenhouse gas emissions.

However, the conventional method of producing hydrogen from water by electrolysis requires high temperatures and pressures, and uses expensive catalysts made of rare metals like iridium. These factors limit the scalability and affordability of hydrogen production. According to a report by TERI, in 2020, India’s hydrogen demand stood at 6 million tons (MT) per year, but most of it was met by fossil fuel-based sources, resulting in significant carbon footprint .

To overcome these challenges, scientists have been exploring alternative ways of producing hydrogen from water, such as using additives that can lower the energy demand and enhance the efficiency of the process. One such additive is urea, which is a common fertilizer and a waste product of animals. Urea can be electrochemically oxidized to produce nitrogen gas and water, while releasing electrons that can be used to reduce water to hydrogen at the cathode.

New Catalyst

A team of scientists from the Centre for Nano and Soft Matter Sciences (CeNS) in Bengaluru has developed a new catalyst that can overcome these limitations and perform urea oxidation reaction (UOR) efficiently. The new catalyst is composed of neodymium nickelate (NdNiO3), which is a non-noble metal oxide with metallic conductivity. The team found that NdNiO3 can be electrochemically activated to form Ni3+-rich sites on its surface, which can directly oxidize urea to nitrogen gas and water without undergoing any degradation or reconstruction.

The team used various techniques, such as X-ray absorption spectroscopy, electrochemical impedance spectroscopy and Raman spectroscopy, to characterize the structure and mechanism of the new catalyst under operating conditions. They also collaborated with Giner Inc., a US-based company specializing in electrolyzers and fuel cells, to test the performance of the new catalyst in a proton exchange membrane (PEM) electrolyzer, which is a cutting-edge technology that can efficiently split water into hydrogen and oxygen at near-room temperature.

The results showed that the new catalyst exhibited superior reaction kinetics, stability and selectivity compared to NiO-based catalysts. The new catalyst also reduced the overall cell potential by about 30%, thereby lowering the energy demand for hydrogen production by urea-assisted water splitting.

Dr. Neena S. John, one of the lead researchers of the team, said: “Our work demonstrates that NdNiO3 is an excellent candidate for UOR in PEM electrolyzers. It has several advantages over NiO-based catalysts, such as higher activity, stability and selectivity, lower cost and abundance of elements. We believe that this catalyst can pave the way for large-scale production of green hydrogen using urea as an additive.”

Conclusion

The discovery of the new catalyst by CeNS scientists is a significant breakthrough in the field of hydrogen production, as it offers a low-cost and energy-efficient solution for generating clean hydrogen from water using urea as an additive. The new catalyst is also composed of elements that are abundant on Earth, unlike rare metals like iridium. The new catalyst could pave the way for large-scale production of green hydrogen for various applications, such as transportation and industry.

The Ministry of New and Renewable Energy is implementing the National Green Hydrogen Mission, approved by the Union Cabinet on 4th January 2023, with an outlay of ₹ 19,744 crore. The overarching objective of the Mission is to make India the Global Hub for production, usage and export of Green Hydrogen and its derivatives . India plans to achieve 5 million metric tons (MMT) per annum of green hydrogen production capacity by 2030 and expects capacity to eventually reach 10 MMT per annum, depending on the growth of the export market .

The Union Minister for New & Renewable Energy and Power Shri R. K. Singh, in a written reply to a question, in Lok Sabha on December 21, 2023, said: “India’s Green Hydrogen production capacity is likely to reach 5 MMT per annum by 2030, contributing to reduction in dependence on import of fossil fuels. Achievement of Mission targets is expected to reduce a cumulative ₹ 1 lakh crore worth of fossil fuel imports by 2030. This is likely to leverage over ₹8 lakh crore in total investments and create over 6 lakh jobs.”

The team’s work was published in ACS Catalysis, a journal dedicated to publishing experimental and theoretical research on catalytic materials .

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