Researchers at UNIST, POSTECH and the University of Pennsylvania have created a new perovskite-based nanocatalyst that can be used to recycle major greenhouse gases, such as methane (CH4) and carbon dioxide (CO2), into valuable hydrogen (H2) gas.

The new catalyst is hoped to promote various waste-to-energy conversion technologies, as it has over twice the conversion efficiency from CH4 to H2 than the traditional electrode catalysts.

Led by Professor Gun-Tae Kim in the School of Energy and Chemical Engineering at Ulsan National Institute of Science and Technology (UNIST), the group of researchers designed a new technique to improve the stability and performance of catalysts used in the reaction (i.e., dry reforming of methane, DRM) that synthesizes H2 and carbon monoxide (CO) from major greenhouse gases.

Nickel (Ni)-based metal complexes are catalysts used conventionally for the dry reforming of methane (DRM). However, after a period of time, the performance and service life of the catalysts degrade due to the accumulation of carbon on the surface of the catalysts.

"The uniform and quantitatively controlled layer of iron (Fe) via atomic layer deposition (ALD) facilitates the topotactic exsolution, increasing finely dispersed nanoparticles", Sangwook Joo, Combined MS/PhD, Study First Author, School of Energy and Chemical Engineering, UNIST.

Moreover, the researchers established that exsolution is facilitated even with tiny amounts of ALD-deposited Fe oxide (Fe2O3).

"Notably, at 20 cycles of Fe oxide deposition via ALD, the particle population reaches over 400 particles (Ni-Fe alloys). As these particles are composed of Ni and Fe, they also exhibited high catalytic activity", Arim Seong, Combined MS/PhD, Study Co-First Author, School of Energy and Chemical Engineering, UNIST.

The new nanocatalyst showed high catalytic activity for the DRM process without any evident degradation in performance for over 410 hours of nonstop operation. The results also revealed a high methane conversion (more than 70%) at 700 °C.