LAUSR

Electrocatalytic nitrogen reduction reaction (NRR) is a complementary route to the traditional Haber‐Bosch process. Boosting the reaction kinetics of electrocatalytic NRR is key to promote the NH3 yield. Herein, we demonstrate that the confinement of reactive intermediates (e. g., *N2) in highly ordered blue TiO2 nanotubes (b‐TiO2) can significantly enhance the surface reaction rate of electrocatalytic NRR on the encapsulated metal oxide catalysts. The enhancement of the reaction rate of NH3 synthesis is attributed to the increased surface coverage of intermediates inside the b‐TiO2 nanotubes. Benefiting from the confinement effect of intermediates, the b‐TiO2 nanotubes enclosing metal oxide electrodes show both higher production rate and Faradaic efficiency of NH3 than the combined ones of individual metal oxide and b‐TiO2 electrodes.