MoO3 nanosheets act as an efficient electrocatalyst for N2 fixation to NH3 with excellent selectivity at ambient conditions. In 0.1 M HCl, they show high activity with an NH3 yield of 4.80 × 10−10 mol s−1 cm−2 (29.43 μg h−1 mgcat.−1) and a faradaic efficiency of 1.9%.

No abstract

A highly attractive, but still a key challenge, is the development of earth-abundant electrocatalysts for efficient NH3 electrosynthesis via the N2 reduction reaction (NRR). In this communication, we report the development of a Mo2N nanorod as a highly efficient and selective NRR electrocatalyst for artificial N2 fixation in acidic electrolytes under ambient conditions. In 0.1 M HCl, this catalyst achieved a high Faradaic efficiency of 4.5% with a NH3 yield of 78.4 μg h-1 mgcat.-1 at -0.3 V vs. a reversible hydrogen electrode, thus outperforming most reported NRR electrocatalysts under ambient conditions and some under harsh conditions. Density functional theory calculations revealed that the free energy barrier of the potential determining step of NRR on MoO2 decreases dramatically after nitrogenization.

Electrohydrogenation of N2 to NH3 is emerging as an environmentally benign strategy to tackle the issues associated with the energy-intensive, CO2-emitting Haber–Bosch process. However, the method is severely challenged by N2 activation and needs efficient N2 reduction reaction (NRR) catalysts. Here, we report that multishelled hollow Cr2O3 microspheres (MHCMs), which are synthesized by a facile synthetic route, can serve as efficient and selective non-noble metal electrocatalysts for NRR. In 0.1 M Na2SO4 solution, the MHCMs achieve a high Faradaic efficiency (6.78%) and a large NH3 yield (25.3 μg h–1 mgcat –1) at −0.9 V vs reversible hydrogen electrode. The MHCMs also exhibit high stability during the reaction. Density functional theory calculations suggest that NRR over MHCMs occurs via both distal associative and partially alternative routes.