Photocatalytic fixation of nitrogen to ammonia by NiFe-LDH-derived sulfide microspheres

Direct fixation of nitrogen (N 2 ) to ammonia (NH 3 ) under ambient conditions via photocatalysts is a promising method to relieve the pressure of energy shortage, where chemisorptions of torpid nitrogen and delivery of photoproduced electrons to N≡N bond are recognized technical limitations. In this work, we have developed the catalysts of NiFe-LDH-derived sulfides microspheres ([NiFe]S) with excellent photocatalytic activity for reduction of N 2 to NH 3 . Excitingly, the NH 3 generation rates of [NiFe]S catalysts reached up to 111.83 μmol · L −1 · h −1 under visible light irradiation in water, which were 10.35 times than that of NiFe-LDH microspheres. The reason was due to the higher photo-induced carrier separation and transmission efficiency of [NiFe]S microspheres. In addition, the possible photocatalytic mechanism was proposed. This new work could guide the design of efficient catalysts and open up the application of metal sulfides in photocatalytic N 2 fixation.