Aqueous Rechargeable Zn–N₂ Battery Assembled by Bifunctional Cobalt Phosphate Nanocrystals-Loaded Carbon Nanosheets for Simultaneous NH₃ Production and Power Generation

Abstract

Developing cost-effective and controllable technologies beyond traditional overall N2 electrocatalysis is critical for the large-scale production of NH3 through electrochemical N2 reduction reaction (NRR) under ambient conditions. Herein, the aqueous rechargeable Zn–N2 battery, assembled by coupling the bifunctional cobalt phosphate nanocrystals-loaded heteroatoms-doped carbon nanosheets (CoPi/NPCS) as cathode electrocatalyst and the commercial Zn plate as anode with KOH electrolyte, was fabricated for the sustainable reduction of N2 to NH3 and power generation during discharge process. Benefiting from the desirable active components of cobalt phosphate nanocrystals and the synergistic effect between nanocrystals and carbon substrates, the CoPi/NPCS catalyst exhibits the enhanced NRR and oxygen evolution reaction (OER) performance in alkaline electrolyte. And the cobalt phosphates are confirmed as active components through the associative pathway toward NRR. When measured in the flow battery configuration with gas diffusion electrode by flowing N2 during discharge, this CoPi/NPCS-catalyzed Zn–N2 battery enables the high N2-to-NH3 yield rate of 14.7 μg h–1 mgcat. –1 and Faradaic efficiency of 16.35% at 0.6 V vs Zn2+/Zn, which can be able to maintain stable in discharge processes during cycling tests. Moreover, the impressive power output of the peak power density of 0.49 mW cm–2 and the energy density of 147.6 mWh gzn –1 are still achieved by this Zn–N2 battery, which are both higher than those of previously reported Zn–N2 batteries. This work not only provides the guideline for the rational design of robust and active bifunctional NRR-OER catalysts but also develops a reasonable and promising technology for efficient electrochemical N2-to-NH3 and power generation.

Anchoring Mo Single-Atom Sites on B/N Codoped Porous Carbon Nanotubes for Electrochemical Reduction of N2 to NH3

“…So far, several kinds of catalysts have been proven to be effective in the field of ENRR, including noble metals, , transition metals and their compounds, − and metal-free catalysts. − Although noble metal-based electrocatalysts such as gold, ruthenium, and platinum exhibit excellent performance, − their high cost, poor stability, and low abundance significantly inhibit their large-scale commercial applications. Therefore, nonprecious metal catalysts have been extensively investigated to develop cost-effective and high-performance ENRR electrocatalysts, including MoS 2 , BiVO 4 , Fe 3 O 4 , MnO 2 , Ti 3 C 2 T x , and so forth. − However, limited by the inherent characteristic that N 2 is not readily adsorbed on the metal surface and by the relatively few exposed active sites caused by the larger size of the catalyst, the current catalyst performance for ENRR still needs to be improved. It may be a suitable solution to use a material capable of adsorbing N 2 as a carrier, and loading a metal catalyst to expose more active sites by reducing the catalyst size may be a suitable solution. , The size effect of metal-based catalysts has an important influence on the catalytic activity and selectivity of loaded metal nanomaterials.…”

Introducing oxygen vacancies in a bi-metal oxide nanosphere for promoting electrocatalytic nitrogen reduction

“…In contrast, the chemisorbed N 2 desorption peak temperature of Pristine-NiMnO 3 is 352 °C, implying a stronger electron back-donation effect of oxygen vacancy sites and therefore stronger N 2 activation with oxygen vacancies. 52 As a result, the insertion of oxygen vacancies could considerably promote N 2 chemical adsorption and activation. 450-NiMnO 3 with the highest oxygen vacancy content, as expected, has the highest NRR activity.…”

Recent Advances in Metal–Gas Batteries with Carbon‐Based Nonprecious Metal Catalysts

“…b) Theoretical energy densities and working voltages for various metal-gas batteries. [17][18][19][20][21][22][23][24][25][26][27][28] c) Timeline of the developments of metal-gas batteries with carbon-based nonprecious metal catalysts. [3,13,16,25,[29][30][31][32][33][34][35][36][37] to introduce doped atoms.…”

“…a) Number of publications that include "metal-gas batteries" according to the Web of Science (as of September 2021). b) Theoretical energy densities and working voltages for various metal-gas batteries [17][18][19][20][21][22][23][24][25][26][27][28]. c) Timeline of the developments of metal-gas batteries with carbon-based nonprecious metal catalysts [3,13,16,25,[29][30][31][32][33][34][35][36][37].…”