A team led by Assistant Professor Dr. Munmun Ghosh has been investigating electrocatalytic hydrogen production, a process in which catalysts help split water into hydrogen and oxygen. The efficiency of this reaction depends strongly on the catalyst used. At present, platinum remains the gold standard, but its scarcity and high cost make it impractical for large scale deployment. Seeking alternatives, the Ashoka team tested complexes of different metals such as nickel, cobalt, copper, zinc, and iron paired with specially designed ligands.

Simply put, a ligand is a molecule that binds to a metal to form a complex, explained Dr. Ghosh. In our case, the ligand reduces the energy required for the reaction, making the process more efficient.

The results were striking: nickel ligand complexes showed the strongest potential for hydrogen generation, performing on par with some of the best systems reported to date. Cobalt also proved promising, especially with its relatively low overpotential of 200 millivolts a measure of efficiency compared to platinum’s benchmark of 30 millivolts. By contrast, metals without ligands can require as much as 1 volt, making them highly inefficient.

According to Dr. Deepak Asthana, another member of the team, the ligand was the real game changer. The metal alone can perform the reaction, but at a far greater energy cost. The ligand essentially partners with the metal, sharing the burden and lowering the energy demand, he said.

Beyond efficiency, ligand design also improves catalyst stability. Without a ligand, the metal catalyst may degrade quickly,noted Dr. Ghosh. By designing ligands carefully, we can tune whether they donate or accept electrons, depending on the needs of the reaction.

While nickel ligand complexes are not yet a complete substitute for platinum, the findings mark a significant step forward. This is still early-stage work, said Dr. Asthana. But with further refinements, nickel ligand systems could eventually rival or even replace platinum catalysts.

The research underscores the promise of biomimetic approaches, where scientists draw inspiration from natural processes to develop sustainable energy solutions. As Dr. Ghosh summarized: I observe what nature does and try to replicate it for scientific purposes.

Source: https://bioenergytimes.com/ashoka-university-researchers-develop-promising-nickel-based-catalyst-for-green-hydrogen-production/