Controlled oxygen vacancy engineering on In2O3−x/CeO2−y nanotubes for highly selective and efficient electrocatalytic nitrogen reduction

Abstract

Introducing and adjusting the oxygen vacancies (V_O) of transition metal oxides has been proposed as a significant and effective way to tackle the sluggish nitrogen reduction reaction (NRR) in the electrocatalysis process. In this work, we present the synthesis of an In₂O_3−x/CeO_2−y nanotube with abundant V_Ovia the electrospinning technique, followed by the controlled post-treatment calcination process. It is demonstrated that the electrochemical properties of In₂O_3−x/CeO_2−y are successfully optimized through V_O engineering and the reaction mechanism of the NRR is the dissociative pathway, which remarkably enhanced electronic conduction and the NRR reaction kinetics simultaneously. The optimized In₂O_3−x/CeO_2−y nanotube exhibits excellent NRR catalytic activity and durability, with an outstanding average yield of 26.1 μg h⁻¹ mg_cat⁻¹ while the faradaic current efficiency of 16.1% at −0.3 V is ultrahigh versus the reversible hydrogen electrode. This study offers insights into designing excellent catalysts for the NRR through a combination of the nanotube structure and the adjustment of the V_O strategy.