High-Efficiency N₂ Electroreduction Enabled by Se-Vacancy-Rich WSe_2–x in Water-in-Salt Electrolytes

Abstract

Electrocatalytic nitrogen reduction reaction (NRR) is a promising approach for renewable NH 3 production, while developing the NRR electrocatalysis systems with both high activity and selectivity remains a significant challenge. Herein, we combine catalyst and electrolyte engineering to achieve a high-efficiency NRR enabled by a Se-vacancy-rich WSe 2−x catalyst in water-in-salt electrolyte (WISE). Extensive characterizations, theoretical calculations, and in situ X-ray photoelectron/Raman spectroscopy reveal that WISE ensures suppressed H 2 evolution, improved N 2 affinity on the catalyst surface, as well as an enhanced π-back-donation ability of active sites, thereby promoting both activity and selectivity for the NRR. As a result, an excellent faradaic efficiency of 62.5% and NH 3 yield of 181.3 μg h −1 mg −1 is achieved with WSe 2−x in 12 m LiClO 4 , which is among the highest NRR performances reported to date.

Boosted nitrate electroreduction to ammonia on Fe-doped SnS2 nanosheet arrays rich in S-vacancies

“…1h), providing further evidence for the formation of SVs on Fe-SnS 2 nanosheets. [47][48][49] As shown in the energy-dispersive X-ray (EDX) elemental mapping images (Fig. 1i) of Fe-SnS 2 , Fe, S and Sn elements were evenly distributed, which proved the successful doping of Fe into the Fe-SnS 2 nanosheets.…”

Confinement catalysis of a single atomic vacancy assisted by aliovalent ion doping enabled efficient NO electroreduction to NH3

“…However, the practical application of the NRR is limited by the low conversion efficiency and NH 3 yield, mainly resulting from the chemically inert properties of N 2 . [1][2][3][4][5][6][7] Very recently, the electrocatalytic NO x (NO, NO 2 À , and NO 3 À ) reduction reaction (NO x RR) to yield NH 3 stood out as an alternative to the NRR, thanks to the much easier activation of the N]O bond (204 kJ mol À1 ) than the N^N bond (941 kJ mol À1 ). [8][9][10] NO emitted from factories, power stations, and motor vehicles is one of the main sources of atmospheric contamination.…”

A vacancy engineered MnO2−x electrocatalyst promotes nitrate electroreduction to ammonia

“…At potentials higher than −0.9 V, the reduced FEs are mainly due to the enhanced HER at elevated potentials. [43][44][45][46][47] For comparison, the NO 3 RR performance of OV-free MnO 2 is also evaluated at the same potential ranges, showing a highest NH 3 yield of 0.37 mg h −1 cm −2 and a maximum FE of 35.1% (Fig. 3d), which are much inferior to those of MnO 2−x , suggesting the pivotal role of OVs in substantially boosting the NO 3 RR performance of MnO 2 .…”