Indian scientists build a metal-free catalyst that nears platinum for zinc-air batteries and fuel cells

Platinum is one of the quiet bottlenecks of the clean-energy transition. It is the catalyst of choice for the oxygen reduction reaction (ORR) that powers hydrogen fuel cells and metal-air batteries — but it is scarce, expensive and largely mined outside India. A team of Indian researchers now reports a catalyst made only of carbon, nitrogen, sulphur and hydrogen that comes within striking distance of platinum's performance.

The work, announced by the Ministry of Science and Technology on 7 October 2026 and published in Science Advances, comes from the S N Bose National Centre for Basic Sciences in Kolkata, the Institute of Nano Science and Technology (INST) in Mohali and SRM University, Amaravati. It was led by Dr Pradip Pachfule of SNBNCBS, Prof Ramendra Sundar Dey of INST and Prof Ranjit Thapa of SRM University, Amaravati.

A honeycomb built from light elements

The material belongs to a class called covalent organic frameworks (COFs) — crystalline, highly porous structures assembled from organic building blocks linked by strong covalent bonds. Think of them as molecular scaffolding with precisely designed pores.

The team's lead material, called TTT-DHTD, pairs an electron-accepting triazine-based unit with an electron-donating thiophene-based unit. This donor-acceptor design forms an ultra-porous, honeycomb-like structure. The researchers also reported a related framework, TAPA-DHTD.

Key properties reported:

• Very high surface area — 915 m²/g by BET measurement, giving oxygen molecules plenty of sites to react.
• Stability — the framework remained crystalline in water and degraded only slightly after 24 hours in a strongly alkaline solution.
• No metals at all — eliminating both cost and supply-chain exposure.

How close to platinum?

In electrochemical tests, TTT-DHTD reached a half-wave potential of 0.82 V, compared with 0.85 V for a commercial platinum-on-carbon catalyst — which the ministry describes as about 96% of platinum's performance. It kept working through 120 hours of continuous operation and was tolerant to methanol, a common contaminant that poisons platinum in some fuel-cell designs.

Computer simulations suggest the active sites are triazine nitrogen and thiophene carbon atoms, whose arrangement creates favourable spots for oxygen molecules to bind and react.

Why the oxygen reduction reaction matters

The oxygen reduction reaction is the step in which oxygen molecules accept electrons and combine with water or protons at a device's cathode. It is notoriously sluggish, and without a good catalyst a large fraction of a fuel cell's or metal-air battery's potential energy is lost as heat. That is why platinum, which accelerates the reaction efficiently, has become so entrenched — and why finding a cheap substitute has been a decades-long goal for electrochemists worldwide.

Metal-free catalysts have been explored before, often using doped carbon materials. The advantage of COFs is that their structure can be designed atom by atom, letting researchers place active sites deliberately rather than relying on random defects.

Why zinc-air batteries

The researchers highlight zinc-air batteries as a natural application. These batteries draw oxygen from the air as one of their reactants, which gives them high theoretical energy density, and they use zinc — abundant, cheap and safe. India has domestic zinc production, unlike lithium, nickel or cobalt, which it largely imports.

The weak link in zinc-air batteries has been the air electrode, where oxygen reduction happens. A low-cost, durable, metal-free catalyst could make them more practical for grid storage, backup power and other applications, and the same chemistry is relevant to hydrogen fuel cells.

Context and caveats

This is a laboratory result. There is no commercial product or timeline yet, and scaling COF synthesis, integrating the material into real electrodes and proving durability over thousands of hours remain significant hurdles. The "96%" figure is a comparison of one standard metric under lab conditions, not a full device-level comparison.

Still, the work adds to a growing body of Indian research on cheaper catalysts for energy devices, and it points towards clean-energy technologies built from materials India can source at home — a strategic consideration as the country scales up storage and hydrogen.

Sources

• https://www.science.org/doi/10.1126/sciadv.aee3092
• https://swarajyamag.com/amp/story/science/indian-researchers-develop-metal-free-catalyst-with-near-platinum-performance-for-more-affordable-zinc-air-batteries
• https://ddindia.co.in/2026/10/new-metal-free-porous-material-could-help-make-clean-energy-more-affordable/
• https://english.punjabkesari.com/business/indian-researchers-develop-metalfree-catalyst-to-replace-platinum-to-cut-cleanenergy-costs
• https://businessnewsweek.in/technology/indian-scientists-develop-platinum-free-catalyst-that-could-cut-clean-energy-costs/
• https://observervoice.com/new-metal-free-catalyst-promises-affordable-clean-energy-234140/