“Soft armor” regulates the electrocatalytic microenvironment for nitrate reduction to ammonia to greatly enhance stability†

An interfacial “soft armor” of hydrogel coating on FeOOH nanowire/Ti mesh structures regulates the electrolytic microenvironment, attracts reductive intermediates, prevents catalyst failure, and enables continuous, stable ammonia production from nitrate electrocatalysis for 60 hours at a rate of 8.64 mg h⁻¹ cm⁻², boosting the nitrate-to-ammonia conversion efficiency and durability.