Scientists have developed a cost-effective alternative to platinum for use in hydrogen production, replacing the expensive metal with palladium nanosheets to reduce costs and accelerate the shift to clean energy.
As global temperatures surpass the preindustrial benchmark outlined in the 2015 Paris Climate Agreement, the need for large-scale hydrogen production has become more urgent to accelerate the transition to zero-emission alternatives. However, the widespread adoption of hydrogen technology has been hindered by its dependence on costly platinum-based catalysts, making it economically unfeasible for everyday use.
Novel Hydrogen Development
Dr. Hiroaki Maeda and Professor Hiroshi Nishihara of the Tokyo University of Science (TUS) led a team consisting of other researchers from TUS, as well as contributors from Japan Synchrotron Radiation Research Institute, Kyoto Institute of Technology, RIKEN SPring-8 Center, and the National Institute for Materials Science, Japan. The team produced a breakthrough in hydrogen evolution reaction (HER) technology with their bis(diimino)palladium coordination nanosheets (PdDI), nearly duplicating platinum’s efficiency at a significantly lower cost.
Maeda and Nishihara’s team further advanced their work by developing two versions of their PdDI nanosheets; each produced through a different fabrication method. They fabricated the C-PdDI variant with gas-liquid interfacial synthesis and the E-PdDI variant through electrochemical oxidation.
Exploring multiple avenues for fabrication benefitted the work by identifying the E-PdDI’s performance testing as being extremely close to that of platinum, within 1mV of overpotential. In addition to similar energy usage, the exchange current density matched between E-PdDI and platinum, marking the solution as one of the most efficient catalysts ever developed.
Hydrogen Evolution Reaction Technology
HER is an essential process in manufacturing green hydrogen energy, which involves the electrolytic splitting of water into hydrogen and oxygen components. Catalyst electrodes convert the hydrogen generated at the electrode surface into hydrogen gas (H₂). Traditionally, the process relies on platinum, which is highly effective but extremely expensive, limiting its utility for large-scale production.
Despite cost challenges, HER is currently still considered the most sustainable and environmentally friendly hydrogen production method.
Through a simple synthesis process, the TUS-led team limited the amount of precious metal required to produce highly efficient catalysts as an alternative to pure platinum. The method enabled the team to fabricate palladium-based nanosheets, reducing HER’s reliance on expensive platinum.
“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,” says lead researcher, Dr. Maeda. “Additionally, their sparse metal arrangement reduces material usage. Here, we have successfully developed these nanosheets using palladium metal.”
Putting PdDI Nanosheets to Work
Manufacturing costs aren’t the only issues impacting economic feasibility. The PdDI Nanosheets also displayed strong durability through 12 hours under acidic conditions. This degree of reusability further drives down costs and enhances sustainability, indicating a strong use case for real-world manufacturing.
“Our research brings us one step closer to making H₂ production more affordable and sustainable, a crucial step for achieving a clean energy future,” explains Dr. Maeda.
Meeting Global Goals
The nanosheets offer many carryovers to global environmental goals. The new process meets the United Nations’ Sustainable Development Goals (SDGs), particularly SDG 7—promoting affordable and clean energy—and SDG 9—industry, innovation, and infrastructure. Beyond cost-effectiveness, the nanosheets are highly scalable for hydrogen production, fuel cells, and large-scale energy storage systems.
Removing platinum from HER could also reduce mining-related emissions, limiting the hidden carbon costs that could potentially erode green gains from the switch to hydrogen fuel. Palladium’s density, one-tenth that of platinum, further increases the cost-effectiveness, driving down the need to mine platinum.
The researchers continue optimizing PdDI nanosheets for commercial production to move toward a hydrogen fuel economy.
The team’s new paper, “Synthesis of Bis(diimino)palladium Nanosheets as Highly Active Electrocatalysts for Hydrogen Evolution,” appeared on November 28, 2024, in Chemistry Europe.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.