Constructing Co@TiO₂ Nanoarray Heterostructure with Schottky Contact for Selective Electrocatalytic Nitrate Reduction...

Electrochemical nitrate (NO₃ ^- ) reduction reaction (NO₃ ^- RR) is a potential sustainable route for large-scale ambient ammonia (NH₃ ) synthesis and regulating the nitrogen cycle. However, as this reaction involves multi-electron transfer steps, it urgently needs efficient electrocatalysts on promoting NH₃  selectivity. Herein, a rational design of Co nanoparticles anchored on TiO₂  nanobelt array on titanium plate (Co@TiO₂ /TP) is presented as a high-efficiency electrocatalyst for NO₃ ^- RR. Density theory calculations demonstrate that the constructed Schottky heterostructures coupling metallic Co with semiconductor TiO₂  develop a built-in electric field, which can accelerate the rate determining step and facilitate NO₃ ^- adsorption, ensuring the selective conversion to NH₃ . Expectantly, the Co@TiO₂ /TP electrocatalyst attains an excellent Faradaic efficiency of 96.7% and a high NH₃  yield of 800.0 µmol h^-1  cm^-2  under neutral solution. More importantly, Co@TiO₂ /TP heterostructure catalyst also presents a remarkable stability in 50-h electrolysis test.