Highly efficient electrochemical ammonia synthesis using superhydrophobic nanoporous silver

Electrochemical nitrogen reduction reaction (ENRR) under ambient conditions offers a greatly promising alternative to the highly-polluting Haber-Bosch process for the production of ammonia. However, due to their unsatisfactory catalytic efficiency, and fussy and costly fabrication process, noble metal-based electrocatalysts can hardly promote the ammonia yield rate for industrial application efficiently. Herein, nanoporous silver structures with a superhydrophobic surface are fabricated via a simple approach. The porous network can afford more active catalytic sites and accessible channels for reactant species. Besides, the hydrophobic surface is achieved by functionalizing with 1H,1H,2H,2H-perfluorodecanethiol (PFDT) on the ligament surface and can weaken the absorbability of H on the catalyst surface, thereby suppressing the occurrence of hydrogen evolution reaction and enhancing ENRR. Hence, superhydrophobic nanoporous silver (SHNPS) displays a superior ammonia faradaic efficiency of (31.1 +/- 1.0)% and high ammonia yield of (33.5 +/- 1.7) mu g h(-1) cm(-2), outperforming the ENRR performance of solid silver nanoparticles and hydrophilic nanoporous silver (NPS). Moreover, our catalyst structure also exhibits high electrochemical stability and excellent selectivity. Notably, the design of a hydrophobic nanoporous catalyst provides a valuable practical strategy for ENRR and other gas-relevant electrochemical reactions.

Automated summary

Nanoporous silver structures with a superhydrophobic surface were fabricated, which showed superior electrochemical nitrogen reduction reaction (ENRR) performance under ambient conditions. It exhibited higher ammonia yield and faradaic efficiency, as well as excellent electrochemical stability and selectivity. This hydrophobic nanoporous catalyst design provides a valuable practical strategy for ENRR and other gas-relevant electrochemical reactions.