Ni–N Interfacial Engineering Enables Noble-Metal-Free Ammonia Photodecomposition

Abstract

A noble-metal-free Ni–NC@TiO₂ core–shell photocatalyst was developed for efficient hydrogen production from ammonia photodecomposition under visible light without the use of sacrificial agents. In this architecture, Ni nanoparticles are anchored on the nitrogen-doped carbon shell through strong Ni–N interfacial coordination. The conductive NC shell promotes the separation and transport of photogenerated charge carriers, while the Ni sites provide favourable centres for NH₃ adsorption and dehydrogenation. Under visible-light irradiation, Ni–NC@TiO₂ exhibits a hydrogen evolution rate approximately 43 times higher than that of pristine TiO₂. Combined experimental characterizations and DFT calculations reveal that the interfacial Ni–N coupling not only accelerates carrier migration, but also modulates the electronic structure of the Ni sites, thereby lowering the reaction barrier for NH3 decomposition. Meanwhile, the catalyst shows excellent durability, maintaining stable activity over 40 h without detectable deactivation.