Purin Molecule Increases Water-to-Hydrogen Reaction Activity Fourfold and Reduces Platinum Costs.

A study by Chiba University in Japan has brought a breakthrough for large-scale hydrogen production from water. Scientists discovered that modifying platinum cathodes with natural purine bases (such as caffeine and theophylline) can increase hydrogen evolution reaction (HER) activity by more than four times, while significantly reducing platinum usage in electrolyzers, contributing to lower green hydrogen costs.

Currently, hydrogen production from water faces economic challenges due to high electrolyzer costs, with prices reaching $2,000–2,600 per kW in 2024. The US Department of Energy (DOE) has set targets to reduce green hydrogen costs to $2 per kg by 2025 and $1 per kg by 2030. The research, led by Dr. Kensuke Tanaka and Professor Masashi Nakamura of the Chiba University Graduate School of Engineering, was published online on September 4, 2025, and appeared in the International Journal of Hydrogen Energy, Volume 172, on September 26.

TheTechnical Principlelies in: during electrolysis, hydrogen ions (H⁺) must first adsorb onto the catalyst; in alkaline media, breaking the O–H bond of water by the catalyst increases energy consumption. However, purine derivatives (such as caffeine, xanthine, purine, theophylline, and theobromine) can promote hydrogen adsorption and accelerate the reaction even under alkaline conditions. Among them, purine and theophylline increased HER activity by 4.2 times and 5 times, respectively. Structural analysis revealed that purine molecules form a cage-like hydrogen bond network with surrounding water, which facilitates OH⁻ removal and lowers the energy barrier for HER.

Professor Masashi Nakamura pointed out that the scarcity of platinum limits the scalability of water electrolysis and fuel cell technologies;reducing platinum loading is key. This method uses naturally abundant materials, combining scalability and environmental protection, which can both lower hydrogen production costs and improve the energy conversion efficiency of hydrogen production systems. It holds significant importance for achieving carbon neutrality through renewable energy-powered water electrolysis.