Cu–Co synergy enabling efficient tandem nitrate reduction to ammonia on engineered TiO 2 nanofibers

Atomically dispersed Cu–Co dual active sites on TiO 2 nanofiber supports: Cu atoms primarily adsorb and activate *NO 3 , while Co atoms efficiently supply *H to intermediates via H 2 O dissociation, thereby suppressing the HER and promoting the NO 3 RR.