Fe2P nanoparticle-decorated porous biochar for high-efficiency electrosynthesis of ammonia from toxic nitrite

Nitrite ion (NO2−) is highly toxic and poses a threat to human health. Aiming to address the shortcomings of traditional methods to remove NO2−, we chose electrochemical technology to reduce the nitrite to synthesize ammonia. This not only eliminates NO2− pollution but is also a greener alternative to the conventional, energy-intensive Haber-Bosch process. The use of electrochemical technology for the reduction of nitrite required the development of an efficient catalyst. Transition metal phosphides are known to have metallic properties and good electrical conductivity, which are promising for electrocatalytic applications. Because the activity of the catalyst is highly dependent on the homogeneous dispersion of the active metal, biochar produced from almond shells, which have a porous structure and large specific surface area, was selected as the carrier on which to load Fe2P. The catalytic activity is clearly demonstrated by an NH3 yield rate of 27107.2 μg∙h−1∙mgcat−1 and a Faradaic efficiency of 96.8 % at −0.5 V versus the reversible hydrogen electrode (RHE). Additionally, the catalyst was satisfactorily sustainable with good stability.