Photocatalytic ammonia synthesis via nitrate reduction on Cu nanoparticle decorated hollow SrTiO3 nanospheres

Overcoming the problems of high dissociation energy and slow activation of N2, photocatalytic nitrate reduction to ammonia (PcNRA) is considered a sustainable and more advantageous approach compared to N2 fixation. Additionally, removing water pollution and converting waste nitrates into valuable ammonia is attracting attention as an eco-friendly alternative to ammonia production technology. However, it suffers from low ammonia selectivity and yield. In this study, hollow SrTiO3 nanospheres decorated with copper nanoparticles were used to increase photocatalytic activity by spatially separating the reduction sites in the outer shell of hollow SrTiO3, prioritizing photocatalytic nitrate reduction to ammonia reaction, and increasing ammonia selectivity using copper nanoparticles. The optimal photocatalyst containing 3 % Cu nanoparticle decoration/ SrTiO3 showed a high ammonia selectivity of 84.1 % and ammonia yield of 2.14 mu mol h-1 and a high apparent quantum yield of 2.8 % at 330 nm, while pristine hollow SrTiO3 nanospheres showed no activity for ammonia production by nitrate reduction.