Research And Development Of Photocatalytic Materials For Ammonia Synthesis

Photocatalytic nitrogen fixation is a promising sustainable and green strategy for NH₃synthesis.Although industrial ammonia synthesis methods can basically satisfy the needs of human production,the emissions of hydrocarbons in the process will exacerbate the earth's greenhouse effect.At present,the existing photocatalysts have the disadvantages of complex synthesis methods and unstable properties.The development of an efficient photocatalyst is the key to make this approach applicable.In this work,MoO_3-x nanobelts are synthesized by a hydrothermal method,and they are firstly utilized as photocatalysts for N2 fixation without using sacrificial reagents and precious-metal co-catalysts at room temperature and atmospheric pressure.The structure and properties of the catalyst are very stable,which can realize nitrogen fixation for more than 24 hours It is found that oxygen vacancies(O_VS)are located on the?001?and?100?planes by STEM analysis.The surface O_VS can chemisorb the N2 molecules by a side-on model on?001?while an end-on model on the?100?plane and elongate their bond length,playing a critical role in the photocatalytic N2 fixation activity.This result provides a new insight into developing efficient photocatalysts with original oxygen vacancies.In addition,BiOBrx Cl1-x was synthesized by solvent-heat method,and a series of characterization showed that the material was a solid solution rather than a composite structure.By comparing the results of Nessler reagent and ion chromatography,we found that the measurement results of Nessler reagent were easily affected by the aldehyde group produced by degradation.Although in the stage experiment,the direct synthesis of solid solution did not show the performance of photocatalytic nitrogen fixation.In the next step,the surface defects will be manufactured and the synthesis conditions will bechanged to further explore the potential of nitrogen fixation of the material.