Confinement of Intermediates in Blue TiO₂ Nanotube Arrays Boosts Reaction Rate of Nitrogen Electrocatalysis

Abstract

Abstract 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 NH 3 yield. Herein, we demonstrate that the confinement of reactive intermediates (e. g., *N 2 ) in highly ordered blue TiO 2 nanotubes (b‐TiO 2 ) can significantly enhance the surface reaction rate of electrocatalytic NRR on the encapsulated metal oxide catalysts. The enhancement of the reaction rate of NH 3 synthesis is attributed to the increased surface coverage of intermediates inside the b‐TiO 2 nanotubes. Benefiting from the confinement effect of intermediates, the b‐TiO 2 nanotubes enclosing metal oxide electrodes show both higher production rate and Faradaic efficiency of NH 3 than the combined ones of individual metal oxide and b‐TiO 2 electrodes.