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

Article abstract of DOI:10.1002/anie.202109785

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.