2D Higher-Metal Nitride Nanosheets for Solar Steam Generation.

ABSTRACT

Higher-metal (HM) nitrides are a fascinating family of materials being increasingly researched due to their unique physical and chemical properties. However, few focus on investigating their application in a solar steam generation because the controllable and large-scale synthesis of these materials remains a significant challenge. Herein, it is reported that higher-metal molybdenum nitride nanosheets (HM-Mo5 N6 ) can be produced at the gram-scale using amine-functionalized MoS2 as precursor. The first-principles calculation confirms amine-functionalized MoS2 nanosheet effectively lengthens the bonds of MoS leading to a lower bond binding energy, promoting the formation of MoN bonds and production of HM-Mo5 N6 . Using this strategy, other HM nitride nanosheets, such as W2 N3 , Ta3 N5 , and Nb4 N5 , can also be synthesized. Specifically, under one simulated sunlight irradiation (1 kW m-2 ), the HM-Mo5 N6 nanosheets are heated to 80 °C within only ≈24 s (0.4 min), which is around 78 s faster than the MoS2 samples (102 s/1.7 min). More importantly, HM-Mo5 N6 nanosheets exhibit excellent solar evaporation rate (2.48 kg m-2  h-1 ) and efficiency (114.6%), which are 1.5 times higher than the solar devices of MoS2 /MF.