Enhancing Green Ammonia Electrosynthesis Through Tuning Sn Vacancies in Sn-Based MXene/MAX Hybrids.

Renewable energy driven N ₂ electroreduction with air as nitrogen source holds great promise for realizing scalable green ammonia production. However, relevant out-lab research is still in its infancy. Herein, a novel Sn-based MXene/MAX hybrid with abundant Sn vacancies, Sn@Ti ₂ CT _X /Ti ₂ SnC-V, was synthesized by controlled etching Sn@Ti ₂ SnC MAX phase and demonstrated as an efficient electrocatalyst for electrocatalytic N ₂ reduction. Due to the synergistic effect of MXene/MAX heterostructure, the existence of Sn vacancies and the highly dispersed Sn active sites, the obtained Sn@Ti ₂ CT _X /Ti ₂ SnC-V exhibits an optimal NH ₃ yield of 28.4 µg h ^-1  mg _cat ^-1 with an excellent FE of 15.57% at - 0.4 V versus reversible hydrogen electrode in 0.1 M Na ₂ SO ₄ , as well as an ultra-long durability. Noticeably, this catalyst represents a satisfactory NH ₃ yield rate of 10.53 µg h ^-1  mg ^-1 in the home-made simulation device, where commercial electrochemical photovoltaic cell was employed as power source, air and ultrapure water as feed stock. The as-proposed strategy represents great potential toward ammonia production in terms of financial cost according to the systematic technical economic analysis. This work is of significance for large-scale green ammonia production.
(© 2023. The Author(s).)