Built-in Electric Field Triggered Interfacial Accumulation Effect for Efficient Nitrate Removal at Ultra-Low Concentration and Electroreduction to Ammonia

A built-in electric field in electrocatalyst can significantly accumulate higher concentration of NO3- ions near electrocatalyst surface region, thus facilitating mass transfer for efficient nitrate removal at ultra-low concentration and electroreduction reaction (NO3RR). A model electrocatalyst is created by stacking CuCl (111) and rutile TiO2 (110) layers together, in which a built-in electric field induced from the electron transfer from TiO2 to CuCl (CuCl_BEF) is successfully formed . This built-in electric field effectively triggers interfacial accumulation of NO3- ions around the electrocatalyst. The electric field also raises the energy of key reaction intermediate *NO to lower the energy barrier of the rate determining step. A NH3 product selectivity of 98.6 %, a low NO2- production of <0.6 %, and mass-specific ammonia production rate of 64.4 h(-1) is achieved, which are all the best among studies reported at 100 mg L-1 of nitrate concentration to date.

Automated summary

The built-in electric field in the electrocatalyst significantly accumulates NO3- ions and lowers the energy of reaction intermediates, leading to efficient nitrate removal and NH3 production. The CuCl (111) and rutile TiO2 (110) electrocatalyst shows the best performance among reported studies at 100 mg L-1 of nitrate concentration.