Constructing N-doped γ-graphyne with Ti3+ doped-TiO2 for highly improved photocatalytic performance towards green ammonia yield

The synthesis of ammonia by photocatalytic N2 reduction is one of the state-of-the-art routes to access clean and renewable energy. In the present study, we synthesize 2D N-doped gamma-graphyne via a mechanochemical route, which is then introduced in Ti3+-TiO2. N-doped gamma-graphyne helps transfering high-energy charges and improves the separation efficiency of photogenerated charge carriers. Owing to more active sites introduced by pyridinicN, N-doped gamma-graphyne promotes the adsorption and activation of nitrogen on the catalyst surface. Moreover, the intrinsic water oxidation performance of N-doped gamma-graphyne allows easier and faster interfacicl oxygen evolution reaction of Ti3+-TiO2 in the photochemical decomposition of water. Compared with TiO2, the ammonia production rate of the composite photocatalyst is increased by 3-7 times. This study gives inights to the graphyne-like materials utilizing in photocatalytic nitrogen fixation.