Metastable Phase Cu with Optimized Local Electronic State for Efficient Electrocatalytic Production of Ammonia from Nitrate

Abstract

Electrocatalytic nitrate (NO 3 − ) reduction reaction (NITRR) is an inspiring route for ammonia (NH 3 ) synthesis at ambient condition. The metallic Cubased material with low cost and high activity is one of the most promising electrocatalysts for NITRR. However, due to the weaker atomic H * -providing capacity, the produced intermediate-nitrite tends to accumulate on its surface, leading to unsatisfactory NH 3 selectivity and Faradic efficiency (FE). Herein, a novel and facile O 2 /Ar plasma oxidation and subsequent electroreduction strategy is developed to synthesize a kind of metastable phase Cu. Excitingly, the metastable phase Cu demonstrates superior NITRR performance to conventional phase Cu with high NH 4 + selectivity (97.8%) and FE (99.8%). Density function theory (DFT) calculations reveal that the upshift of the d-band center to near the Fermi level in metastable phase Cu contributes to the enhanced activity, while the relatively strong adsorption of H * facilitates the conversion from NO 2 * /NO * to NOOH * /NOH * and thus ensures high selectivity and FE. Furthermore, when evaluated as cathode material in Zn-NO 3 − battery, high power density (7.56 mW cm −2 ) and NH 4 + yield (76 µmol h −1 cm −2 ) are achieved by the metastable phase Cu-based battery.

Laser-controlled tandem catalytic sites of CuNi alloys with ampere-level electrocatalytic nitrate-to-ammonia reduction activities for Zn–nitrate batteries

“…5g and Table S6 (ESI †). 3,[43][44][45][46][47][48][49][50] In addition, NH 3 was collected as liquid ammonia or an ammonium chloride powder from the electrolyte of the Zn-NO 3 À battery, as shown in Fig. S32 and S34 (ESI †).…”

Investigating the role of oxygen vacancies in metal oxide for enhanced electrochemical reduction of NO3− to NH3: mechanistic insights

“…190,191 Likewise, Cu-based materials have exhibited significant outcomes in the electrochemical reduction of NO 3 − to NH 3 . 192,193 As a result, incorporating copper into MnO catalysts could be a beneficial approach for enhancing the reaction efficiency. In their research, Jang et al 194 produced a range of amorphous MnCuO x catalysts with varying concentrations of oxygen vacancies using plasma treatments (Fig.…”

Boosting Nitrate to Ammonia Electroconversion through Hydrogen Gas Evolution over Cu-foam@mesh Catalysts

“…In earlier studies, various transition metals (e.g., Pt, − Pd, Rh, and Ru , ), coinage metals (Au, Ag, and Cu , ), and in some cases oxidic precursors have been successfully applied as NO 3 – RR catalysts. Among the mono-metallic materials studied to date, Ni, Co, and Cu ,,, stand out due to their superior NO 3 – RR activity and selectivity reaching Faradaic efficiencies (FEs) for ammonia above 90% at comparably low overpotentials (for a survey, see the Supporting Information).…”