US electrolysis process could simplify green hydrogen production

Electrolysis - where electricity is passed through water in the presence of catalysts to yield hydrogen and oxygen - is a key process for the production of green hydrogen. However, the process currently relies on expensive noble metal components such as platinum and iridium for catalysts, and the high cost of these materials is though to be a limiting factor in the uptake of green hydrogen production.

In an effort to address this researchers at Georgia Institute of Technology and Georgia Tech Research Institute (GTRI) have designed and demonstrated a new class of hybrid catalysts that reduce the requirements for these expensive materials and, according to principal investigator Professor Seung Woo Lee, demonstrate superior performance for both oxygen and hydrogen spilling.

“We designed a new class of catalyst where we came up with a better oxide substrate that uses less of the noble elements,” he said.

Jinho Park, a research scientist at GTRI and a leading investigator of the research, said this research could help lower the barrier of equipment cost used in green hydrogen production. Besides developing hybrid catalysts, the researchers have finetuned the ability to control the catalysts’ shape as well as the interaction of metals. Key priorities were reducing the use of the catalyst in the system and at the same time, increasing its durability since the catalyst accounts for a major part of the equipment cost.

The group’s work drew on the computational and modelling expertise of research partner, the Korea Institute of Energy Research, and X-ray measurement from Kyungpook National University and Oregon State University, which used the country’s synchrotron, a football-field-sized super x-ray to probe and monitor the structural changes in the catalyst during the water-splitting process at the nanometre scale.

A key finding, according to Park, was the role of the catalyst’s shape in producing hydrogen.

“The surface structure of the catalyst is very important to determine if it’s optimised for the hydrogen production. That's why we try to control the shape of the catalyst as well as the interaction between the metals and the substrate material,” he said.

Park said some of the key applications positioned to benefit first include hydrogen stations for fuel cell electric vehicles, microgrids, and a new community approach to designing and operating electric grids that rely on renewable-driven backup power.

The team's research is published in the journals Applied Catalysis B: Environmental and Energy & Environmental Science