High-Efficiency Electrocatalytic Conversion of Nitrite to Ammonia Using Nickel Phthalocyanine

Nitrite (NO₂ ^-) is a dangerous pollutant that is often found in groundwater sources and endangers human health. In addition to nitrite removal requirements, electrocatalytic nitrite reduction reaction (eNO₂RR) holds promise for value-added ammonia (NH₃) production at room temperature. In this study, a solvothermal technique for the preparation of nickel phthalocyanine (NiPc) is used as a highly active electrocatalyst for the conversion of NO₂ ^- to NH₃ under ambient conditions. The NiPc catalyst shows a remarkable Faradaic efficiency (FE) of 90.1% at -0.9 V versus RHE with maximum ammonia yield rate of 14667 µg h^-1 mg_cat. ^-1 at -1.0 V versus RHE in 0.1 M Na₂SO₄ containing 0.1 M NaNO₂ solution. Furthermore, the catalyst exhibits exceptional long-term stability during chronoamperometry tests. These findings boost the future ammonia production from nitrite reduction for sustainable development.