Reviewed by Lexie CornerMar 4 2025
According to a study published in Chemistry-A European Journal, researchers from the Tokyo University of Science (TUS) have developed a new hydrogen evolution catalyst, bis(diimino)palladium coordination nanosheets (PdDI), which offers platinum-like performance at a significantly lower cost.
Researchers have developed a highly active catalyst to replace platinum-based catalysts for the affordable production of hydrogen. Image Credit: Hiroaki Maeda from Tokyo University of Science, Japan
Hydrogen energy is emerging as an important contributor to a cleaner, more sustainable future, offering a zero-emission alternative to fossil fuels. However, large-scale hydrogen production mainly relies on expensive platinum-based catalysts, presenting a significant cost challenge for the sector.
The journal selected the study as a "Cover Feature," highlighting its importance in advancing sustainable hydrogen production.
Dr. Hiroaki Maeda and Professor Hiroshi Nishihara of TUS led the study in collaboration with researchers from the University of Tokyo, Japan Synchrotron Radiation Research Institute, Kyoto Institute of Technology, RIKEN SPring-8 Center, and the National Institute for Materials Science in Japan. The discovery marks a significant development in hydrogen evolution reaction (HER) technology, a critical process for green hydrogen energy generation.
HER occurs during the electrolytic splitting of water, generating hydrogen. Platinum-based HER catalyst electrodes convert nascent hydrogen ([H]) produced during water splitting into hydrogen gas (H₂). While platinum (Pt) is highly effective as an HER catalyst, its scarcity and high cost increase manufacturing costs, limiting its widespread use.
The research team developed an efficient alternative to Pt catalysts using a simple synthesis method and small amounts of precious metal. They created palladium-based nanosheets with high catalytic activity and minimal metal usage, significantly reducing the cost of hydrogen production.
Developing efficient HER electrocatalysts is key to sustainable H₂ production. Bis(diimino)metal coordination nanosheets, with their high conductivity, large surface area, and efficient electron transfer, are promising candidates. Additionally, their sparse metal arrangement reduces material usage. Here, we have successfully developed these nanosheets using palladium metal.
Dr. Hiroaki Maeda, Researcher, Tokyo University of Science
The team created PdDI nanosheets (C-PdDI and E-PdDI) using two different methods: gas-liquid interfacial synthesis and electrochemical oxidation. After activation, the E-PdDI sheets showed a low overpotential of 34 mV, similar to platinum's overpotential of 35 mV, meaning very little additional energy was needed to start hydrogen production.
The exchange current density of 2.1 mA/cm² matched platinum's catalytic performance. These results place E-PdDI among the most efficient HER catalysts developed to date, making it a promising low-cost alternative to platinum.
Long-term stability is a key factor for any catalyst. The PdDI nanosheets demonstrated excellent durability, remaining intact after 12 hours in acidic conditions, showing they could be used in real-world hydrogen production systems.
“Our research brings us one step closer to making H₂ production more affordable and sustainable, a crucial step for achieving a clean energy future,” explained Dr. Maeda.
PdDI nanosheets support the United Nations' Sustainable Development Goals (SDGs), including SDG 7 (affordable and clean energy) and SDG 9 (industry, innovation, and infrastructure), by reducing the need for expensive platinum. The impact of this discovery goes beyond laboratory results. The scalability, increased activity, and cost-effectiveness of PdDI nanosheets make them suitable for industrial hydrogen production, hydrogen fuel cells, and large-scale energy storage systems.
Replacing platinum-based catalysts with PdDI may also reduce mining-related emissions, helping speed up the transition to a sustainable hydrogen economy. Additionally, palladium atoms are ten times less dense than platinum atoms, reducing the need for platinum and making electrode production more affordable. Replacing platinum with PdDI nanosheets is expected to produce strong results in industries like automotive, hydrogen production, and electrode manufacturing.
As research continues, the TUS team aims to further optimize PdDI nanosheets for commercialization, contributing to the development of a sustainable hydrogen economy.
Journal Reference:
Maeda, H. et. al. (2025) Synthesis of Bis(diimino)palladium Nanosheets as Highly Active Electrocatalysts for Hydrogen Evolution. Chemistry-A European Journal. doi.org/10.1002/chem.202403082