A bifunctional CoNi alloy for electrocatalytically coupled cathodic nitrate reduction and anodic HPAM oxidation

Abstract

The construction of electrocatalytic cathodic nitrate reduction and anodic polyacrylamide (HPAM) oxidation reactions is a promising new electrocatalytic reaction system, which promises simultaneous ammonia synthesis and HPAM degradation. Here, we synthesised an N-doped C nanotube-encapsulated CoNi nano-alloy and used it for electrocatalytic NO₃⁻ reduction and HPAM oxidation reactions. Therein, CoNi-0.5 could achieve the maximum ammonia yield and Faraday efficiency of 5516.73 ± 66.07 μg h⁻¹ mg_cat⁻¹ and 94.71 ± 1.21 %, respectively. Meanwhile, the maximum degradation rate of HPAM was 73.02 ± 1.16 % at 2 h. By In-situ ATR-SEIRAS, in-situ DEMS demonstrated that *NOH is an important reaction intermediate in the ammonia synthesis process, and the bimetallic CoNi alloy can effectively reduce the reaction energy barrier for NO₃⁻ reduction. This work presents a new strategy for constructing a coupled system for electrocatalytic NO₃⁻ reduction.