Construction And Photocatalytic Properties Study Of Mo（W）S₂/Iron Phthalocyanine Heterojunction

As one of the new green technologies with great potential,photocatalytic technology can transform greenhouse gases such as CO₂into high valuable chemicals and fuels through solar energy,which is conducive to solving the problems of fossil fuel shortage and global environmental pollution.However,photocatalytic CO₂reduction involved in complex multiple electrons transfer path,resulting in a large number of products,therefore,how to construct a reasonable photocatalytic system to obtain high selectivity and added value fuel has become a research hotspot.Among the photocatalytic CO₂reduction catalytic materials developed,Mo（W）S₂,with layered structure is considered as an excellent catalyst for photocatalytic CO₂reduction for its suitable band gap and excellent photocatalytic activity.In this paper,the photocatalytic CO₂reduction performance of Mo（W）S₂system was studied by constructing an efficient heterojunction.The MoS₂/Fe Pc and WS₂/Fe Pc heterojunction photocatalysts were prepared by impregnation method,using molybdenum disulfide（MoS₂）,tungsten disulfide（WS₂）and iron phthalocyanine（Fe Pc）as raw materials.The morphology,crystal structure,optical absorption and photoelectric properties of the catalysts were characterized by SEM,TEM,XRD,XPS,Raman,DRS and EIS.The results showed that Mo（W）S₂formed a heterojunction with Fe Pc,which can effectively promote the separation of photogenerated electrons and holes,conducive to the improvement of photocatalytic activity.MoS₂/Fe Pc and WS₂/Fe Pc photocatalysts shows excellent CO₂reduction performance.The CO formation rate of MoS₂/Fe Pc and WS₂/Fe Pc are 214.84μmol·g^-1·h^-1and 364.91μmol·g^-1·h^-1,higher than pure MoS₂and WS₂.Using molybdenum disulfide（MoS₂）,silver nitrate（Ag NO₃）and iron phthalocyanine（Fe Pc）as raw materials,the composite catalyst of ternary heterojunction MoS₂/Ag/Fe Pc was prepared.The morphology,crystal structure,optical absorption and photoelectric properties of the catalysts were characterized by TEM,XRD,XPS,DRS and EIS.The results showed that Ag,as an electron catcher,can further promote electron transfer and inhibit the recombination of photogenerated electrons-holes,which is conducive to improvement photocatalytic activity.MoS₂/Ag/Fe Pc photocatalyst shows excellent CO₂reduction performance and selectivity.Compared with MoS₂/Fe Pc,the selectivity of CO increases from 81.11%to 95.31%,and the by-product H₂generation is effectively inhibited.The CO formation rate of MoS₂/Ag/Fe Pc photocatalyst is 383.28μmol·g^-1·h^-1.Using molybdenum disulfide（MoS₂）,chloro-auric acid hydrate（HAu Cl₄.H₂O）and iron phthalocyanine（Fe Pc）as raw materials,the composite catalyst of ternary heterojunction MoS₂/Au/Fe Pc was prepared.The morphology,crystal structure and photoelectrical properties of the catalysts were characterized by TEM,XRD,XPS,DRS and EIS.The results showed that the formation of the heterojunction will increase the concentration of electron accumulation on the surface of MoS₂,which is conducive to the formation of multi-electron product CH₄.MoS₂/Au/Fe Pc photocatalyst shows excellent CO₂reduction performance.The CH₄formation rate of MoS₂/Au/Fe Pc is 414.28μmol·g^-1·h^-1,and the selectivity of CH₄is 71.16%.