Ag-Ni(OH)<sub>2</sub>/Cu Heterostructure for Tandem Electrocatalytic Nitrate Reduction to Ammonia Coupled with 5-Hydroxymethylfurfural Electrooxidation
Xue Chen, Yuexuan He, Guopeng Ding, Zixuan Feng, Qianling Wei, Chunyu Sui, Zhili Wang, Qing Jiang
Abstract
Electrochemical reduction of nitrate ions to NH 3 provides a sustainable route for both NH 3 synthesis and wastewater treatment, but it remains challenging. Here we report a Ag-Ni(OH) 2 /Cu NW heterostructure that exhibits a high NH 3 Faraday efficiency of 97.3% with an NH 3 yield rate of 4.01 mg h –1 cm –2 at −0.1 V vs RHE. Theoretical studies reveal that the excellent performance of Ag-Ni(OH) 2 /Cu NW results from the multisite synergy via a cascade electrocatalysis, in which Ag and Ni(OH) 2 species promote NO 3 – reduction to NO 2 – and H 2 O dissociation to generate *H, respectively, and Ni(OH) 2 /Cu interface accelerates NO 2 – reduction to NH 3 . Meanwhile, using Ag-Ni(OH) 2 /Cu NW as both the anode and cathode, a two-electrode system integrating the nitrate reduction reaction with the 5-hydroxymethylfurfural oxidation reaction achieves 98.1% NH 3 Faraday efficiency with a 3.17 mg h –1 cm –2 NH 3 yield rate and 99.7% 2,5-furandicarboxylic acid selectivity with 99.2% 5-hydroxymethylfurfural conversion.