Copper single-atom catalyst as a high-performance electrocatalyst for nitrate-ammonium conversion

Conjugated Coordination Polymer as a New Platform for Efficient and Selective Electroreduction of Nitrate into Ammonia

“…− features an appreciably increased current density than that tested in the electrolyte without NO 3 − , verifying the electrochemical reduction process. As shown in Figure S11 (Supporting Information), the 1 H nuclear magnetic resonance (NMR) spectra of electrolyte adopting 15 NO 3 − as reactants show typical double peaks of 15 NH 4 + at δ = 6.99 and 7.17 ppm, while the 1 H NMR spectra of electrolyte adopting 14 NO 3 − as reactants show typical triple peaks of 14 NH 4 + at δ = 6.95, 7.08, and 7.21 ppm, [7] thus confirming that the generation of NH 3 is originated from the electroreduction of NO 3 − . Besides, negligible NH 3 products were detected for the control tests in electrolytes without NO 3 − or applied external potential, eliminating the interferences from the electrocatalyst itself and electrolyte (Figure S12, Supporting Information).…”

“…[11] In recent years, a variety of electrocatalysts including metal alloys, metal oxides, carbon materials and single-atom catalysts have been investigated for enhancing the NRA catalysis. [7,[12][13][14] Among these developed catalysts, single-atom catalysts (SACs) have proven their great potential because of their maximized metal-utilization efficiency, good adjustability of electronic structures and catalytic sites. [15,16] Although significant progress has been made, the catalytic performance of SACs toward NRA is still far from the requirements of industrial-scale NH 3 synthesis.…”

“…Previous studies indicated that the properties of metal centers combined with their coordination atoms would affect the adsorption/activation of NRA intermediates and thereby the overall reaction kinetics. [14,[16][17][18] Stronger binding of NRA intermediates over HER intermediates on the metal sites would exhibit possibly higher selectivity but lower Electroreduction of nitrate into ammonia (NRA) provides a sustainable route to convert the widespread nitrate pollutants into high-value-added products under ambient conditions, which unfortunately suffers from unsatisfactory selectivity due to the competitive hydrogen evolution reaction (HER). Previous strategies of modifying the metal sites of catalysts often met a dilemma for simultaneously promoting activity and selectivity toward NRA.…”

P-modified single-atom Cu catalyst for enhanced electrocatalytic performance of NO3- reduction to NH3

“…34 The first step was the protonation of NO 3 -, which was solution-mediated proton transfer to HNO 3 without electron transfer. 12,35,36 For Cu-N 4 , the formation of the *NOH intermediate was an endothermic process. However, the *NO hydrogenation step was exothermic after P doping, indicating that P doping made the formation of *NOH easier.…”

“…*NOH) adsorption and therefore a large barrier for the formation of NH 3 . 12 The research by us and other groups show that the d-orbital energy levels of Cu can be adjusted by directly replacing N with heteroatomic sulfur (S) or phosphorus (P). 1,[13][14][15] While the exploration of this strategy on intermediate adsorption and catalytic performance regulations has yet been reported for NO 3 -RR.…”