• Scientists have made significant progress in understanding proton behaviour at catalyst surfaces, paving the way for more efficient green hydrogen production.

• A recent study published in Advanced Energy Materials reveals how carefully designed electrocatalysts can optimise the hydrogen evolution reaction (HER), a crucial process for sustainable hydrogen generation.

• The research team from the Institute of Nano Science and Technology (INST), Mohali, focused on metal-oxide-semiconductor (MOS) based p-n heterojunctions.

• Supported by India’s Department of Science and Technology (DST), this research underscores the country's growing leadership in clean energy innovation. 

• These structures create a strong built-in electric field (BIEF) due to their asymmetric electronic environments, which significantly improves hydrogen production efficiency. 

• By analysing critical parameters like work function differences, BIEF strength, and Gibbs free energy, scientists gained new understanding of how to optimise proton adsorption and desorption — fundamental steps in the hydrogen generation process.

• The INST team developed a novel catalyst by growing copper tungsten oxide (CuWO4) nanoparticles on a copper hydroxide (Cu(OH)2) precursor, creating a CuO-CuWO4 heterostructure. 

• Their electrochemical studies revealed fascinating properties: the proton adsorption energy varies dramatically near the depletion region compared to bulk areas, creating an optimal Gibbs free energy gradient that enhances both hydrogen adsorption and desorption. 

• The catalyst also demonstrates ‘negative cooperativity’, where proton binding at one site reduces affinity at neighbouring sites, further improving the alkaline hydrogen evolution reaction.

• This breakthrough provides crucial insights for designing next-generation electrocatalysts that could revolutionize green hydrogen production. 

• The findings suggest pathways to develop catalysts that offer higher efficiency in water-splitting reactions, lower energy consumption, and more cost-effective solutions for renewable energy storage. 

• As the world transitions to cleaner energy sources, such advancements in hydrogen production technology could play a pivotal role in achieving carbon neutrality across multiple industries.

What is green hydrogen?

• Although hydrogen is the lightest and most abundant element in the universe, it is rarely found in nature in its elemental form and always must be extracted from other hydrogen-containing compounds. It also means that how well hydrogen contributes to decarbonisation depends on how clean and green the method of production is.

Based on the sources and processes, hydrogen can be classified into various colours:

i) Black/Brown/Grey hydrogen is produced by coal or lignite gasification (black or brown), or via a process called steam methane reformation (SMR) of natural gas or methane (grey). These tend to be mostly carbon-intensive processes.

ii) Blue hydrogen is produced by natural gas or coal gasification combined with carbon capture storage (CCS) or carbon capture use (CCU) technologies to reduce carbon emissions.

iii) Green hydrogen is produced using electrolysis of water with electricity generated by renewable energy. The carbon intensity ultimately depends on the carbon neutrality of the source of electricity. Which means, the more renewable energy there is in the electricity fuel mix, the “greener” the hydrogen produced.

Additional Read: 

National Green Hydrogen Mission

In January 2023, Prime Minister Narendra Modi-led Cabinet approved the National Green Hydrogen Mission with an outlay of Rs 19,744 crore. The Mission is expected to attract Rs 8 lakh crore of investment in the green hydrogen chain. 

(The author is a trainer for Civil Services aspirants.)