| Traditional Haber-Bosch method for ammonia synthesis is restricted in further development and application due to its high energy consumption,high carbon emissions,limited raw materials,and high production costs.Photocatalysis,a green and sustainable chemical technology that utilizes light energy for chemical reactions,has become an important research direction for future clean chemical technology.However,the photocatalytic synthesis of ammonia also faces challenges,such as the weak adsorption capacity of materials for N2 and high carrier recombination efficiency.This work investigates the influence of microstructure on the photocatalytic performance of molybdenum oxide materials as typical photocatalysts for ammonia synthesis.（1）In this work,a photocatalytic material MoO3·0.55H2O was designed by introducing crystal water.The influence of crystal water on the photocatalytic performance of molybdenum oxide for ammonia synthesis was explored through experiments and theoretical calculations.The results show that the NH3 production of MoO3·0.55H2O photocatalytic material under visible light irradiation can reach 82.6μmol·gcat-1 within 60 min,which is about 4.3 times that of MoO3.The Jahn-Teller distortion of molybdenum oxides caused by crystal water coordination and the resulting Lewis acid sites and the low-valence Mo5+empty d orbitals jointly enhance the adsorption and activation of N2.Photoelectrochemical characterization proves that MoO3·0.55H2O has higher light utilization efficiency and lower recombination efficiency of photogenerated carriers.In addition,density functional theory calculations were performed to theoretically demonstrate the excellent photocatalytic ammonia synthesis performance of MoO3·0.55H2O.This work provides a data basis for designing crystal water-rich photocatalytic materials.（2）In this work,Ag@MoO3·0.55H2O with different ratios of Ag modification were designed by a simple photoreduction method.The influence of Ag modification on the photocatalytic performance of molybdenum oxide for ammonia synthesis was explored through experiments and theoretical calculations.The results show that under visible light conditions,the NH3 production of 2%Ag@MoO3·0.55H2O photocatalytic material within 60 min can reach242.0μmol·gcat-1,which is about 2.8 times that of MoO3·0.55H2O photocatalytic material under the same conditions.The excellent photocatalytic ammonia synthesis performance is attributed to the localized surface plasmon resonance effect of noble metal Ag and the successful construction of Schottky junction,which improves the light utilization efficiency of Ag@MoO3·0.55H2O and reduces the recombination efficiency of photogenerated carriers.In addition,density functional theory calculations were performed on Ag@MoO3·0.55H2O,which theoretically proved the excellent photocatalytic ammonia synthesis performance of Ag@MoO3·0.55H2O.Overall,this demonstrates that Ag@MoO3·0.55H2O is an excellent photocatalytic material for ammonia synthesis. |
