CoS 2 @TiO 2 nanoarray: a heterostructured electrocatalyst for high-efficiency nitrate reduction to ammonia.

Electrochemical nitrate (NO 3 - ) reduction emerges as a promising strategy to maintain the balance of the global nitrogen cycle and an alternative to nitrogen electroreduction for ambient ammonia (NH 3 ) synthesis. However, the complicated multiple-electron transfer process of NO 3 - -to-NH 3 conversion demands catalysts with high selectivity for NH 3 production. Herein, CoS 2 nanoparticle decorated TiO 2 nanobelt array on a titanium plate (CoS 2 @TiO 2 /TP) is reported as a superb electrocatalyst for the NO 3 - reduction reaction. In 0.1 M NaOH containing 0.1 M NO 3 - , CoS 2 @TiO 2 /TP offers a large NH 3 yield of 538.21 μmol h -1 cm -2 at -0.7 V vs. reversible hydrogen electrode (RHE) and a high faradaic efficiency of 92.80% at -0.5 V vs. RHE. Additionally, it also shows strong stability for the 20 h electrolysis test.