Chinese researchers explored a new way of laser irradiation to construct metal–metal oxide interfaces for enhanced electrocatalytic N₂ reduction reaction.

Ammonia (NH₃) is an important industrial raw material that has been widely used in the chemical industry and agricultural production fields.

However, traditional N₂ fixation technology in Haber–Bosch process must suffer harsh conditions, such as consuming massive non-renewable natural resources, causing large global CO₂ emissions.

Hence, it is very significant to develop electrocatalytic N₂ reduction reaction (NRR) for NH₃ formation under ambient conditions.

Previous fundamental structural studies revealed that the interface confinement effect between metals and metal oxides play a significant role in enhancing catalytic activity.

And metallic Pd not only could restrain the side reaction of hydrogen evolution reaction (HER) effectively, but also possesses a higher faradaic efficiency for NRR activity than Pt and Au under similar ambient conditions.

Moreover, PdO could easily absorb subsurface H to imitate ɑ-PdH, which is a stable phase for N₂ activation at operating potentials.

Based on the above, the team successfully prepared PdO/Pd/CNTs heterojunctions with a controllable reduction degree and steerable PdO–Pd interface by a facile method of laser irradiation.

Electrochemical tests proved that PdO/Pd/CNTs irradiated for 10 min possessed the optimal value of PdO–Pd interface and exhibited the highest NRR performance.

This work may help to understand the interfacial interaction of heterojunctions in NH₃ synthesis from N₂ and water, and give a guidance to improve the activity and stability of NRR catalysts.

This research was supported by National Basic Research Program of China, Instrument Developing Project of the Chinese Academy of Sciences, National Natural Science Foundation of China.

Schematic illustration of the construction of PdO/Pd/CNTs by laser irradiation. (Image by LV Jiali)