Preparation Of Iron Series Non-precious Metals Loaded Bi₂MoO₆ And Their Photocatalytic NO Removal Performances

NO_x is a common air pollutant that has adverse effects on ecological environment and human respiratory system.In the past decades,semiconductor-based photocatalytic NO oxidation technology,which is low cost,environmentally friendly,has received much attention.In addition,this technology can effectively remove NO in low level.On account of the inferior efficiency of NO removal,the release of toxic by-product（NO₂）,and the relevant mechanism of oxidation path,this technology needs a further insight.Bismuth molybdate is an extensively studied photocatalytic material with the advantages of a narrow band gap,absorption of visible light,adequate energy level position,and easy modification and variation.In view of this,this paper selects bismuth molybdate as the research object and loads Fe series metals（Fe,Co and Ni）on its surface by precipitation-deposition method to enhance the activities of photogenerated carrier separation,reactant adsorption and activation,and finally to improve photocatalytic NO removal performance,and to study its photocatalytic NO removal mechanism.The studies are as follows:1.The oxygen vacancies-rich Bi₂MoO₆ materials are prepared by the glycol solvent thermal method,and a series of Ni-Bi₂MoO₆ materials are prepared by heat treatment in H₂/Ar atmosphere after adsorption of Ni²⁺on the Bi₂MoO₆ surface.When the Ni loading is1.1 wt.%and the calcination temperature is 300℃（1.1-Ni-Bi₂MoO₆）.The photocatalytic NO removal experiment shows that the material has the highest NO removal efficiency,which achieve a steady removal rate as 70.3%in 40 minutes.The characterization results show that Ni occupies the oxygen vacancies on the surface of Bi₂MoO₆,forming an atomic-level distribution and not forming aggregated singlet nickel particles.On the other hand,Ni-Bi₂MoO₆ has higher photogenerated carrier separation efficiency,reactant adsorption and activation capacity than Bi₂MoO₆ material,which can generate more reactive oxygen species under light.This work provides new ideas for the design of new high-efficiency bismuth molybdate photocatalysts.2.Based on the previous work,a series of Fe-Bi₂MoO₆ and Co-Bi₂MoO₆ materials are prepared by loading Fe and Co on the surface of Bi₂MoO₆ photocatalytic materials in the same way and a comparative performance analysis of three Fe series metal-loaded Bi₂MoO₆photocatalytic materials is also presented.The test results show that the photocatalytic NO removal efficiency of both 1.1-Fe-Bi₂MoO₆ and 1.0-Co-Bi₂MoO₆ materials are higher than that of the single Bi₂MoO₆ material.On the other hand,the photocatalytic performance of the three materials is in the order of Ni-Bi₂MoO₆>Fe-Bi₂MoO₆>Co-Bi₂MoO₆.Experiments such as PL,photocurrent,EIS,TPD,and reactive oxygen species detection show that the Ni-Bi₂MoO₆ material has the fastest photogenerated carrier separation efficiency,the strongest reactant adsorption capacity,and the highest reactive oxygen species generation capacity under light.This work provides a reference for the preparation of metal-loaded semiconductor materials and the study of the conformational relationship of photocatalytic performance.