Study On Preparation And Properties Of Metallic Oxide Based Selfcleaning SERS Substrate

As a powerful spectral technology,surface-enhanced Raman scattering（SERS）has attracted extensive attention in the fields of chemistry,environmental monitoring and public safety due to its super high sensitivity,unique fingerprint peaks specificity and non-destructive detection.However,it remains a challenge to achieve SERS-based sensitive detection for organic molecules with low affinity to the surface of plasma metal.,especially for the Persistent organic pollutants（POPs）,such as polybrominated diphenyl ethers（PBDEs）and polychlorinated biphenyls.POPs molecules had caused great potential harm to our living surroundingthe.In addition,considering the unique photodegradation advantages of metallic oxide semiconductor,the excellent adsorption properties of graphene material and the exceptional SPR effect of gold,the metallic oxide semiconductor/graphene oxide/gold hybrid systems were constructed,achieving sensitive SERS detection and in-situ photocatalytic self-cleaning degradation of pollutant molecules.This paper constructed the metallic oxide/graphene/gold hybrid systems SERS self-cleaning substrate,and explored its SERS detection performance and photocatalytic performance of PBDEs.The important and valuable results are summarized as follows:（1）The flower-like TiO₂ semiconductor micro-nano particles were prepared by solvothermal reduction method,and Au nanoparticles were deposited on the surface of TiO₂ by in-situ reaction method.The effect of different amounts of Au precursor solution on the properties of TiO₂@Au were investigated.In addition,reduced graphene oxide（r GO）layers were loaded on TiO₂@Au hybrid systems by solvothermal reduction method.Finally,we got ternary TiO₂@Au-r GO hybrid systems.It was found that the ternary hybrid systems could realize the sensitive SERS detection of 10^-7 M BDE-47 molecule,and could realize the complete degradation of BDE-47 molecules within 20 h.The analysis showed that the LSPR effect of gold nanomaterials and the good molecular adsorption of r GO layers synergistic enhanced the SERS performance of the substrate.The channels formed during the ternary hybrid systems could help the electron transport,the separation of photogenerated carriers produced the effect of photogenerated charge induced transfer and promoted the improvement of the photocatalytic activity of the substrate.（2）The anisotropic octahedral Cu₂O particles were prepared by in-situ reduction method,and the effects of different reaction temperatures and the amounts of complexing agent for the photocatalytic performance of Cu₂O particles were investigated.Combined with the excellent molecular enrichment capability of graphene oxide（GO）materials,Cu₂O-GO-Au sandwich composite systems were assembled on the membrane substrate by pumping/spinning coating process.The prepared substrate could realize the trace SERS detection of 10^-13 M R6G molecules,and could realize the complete degradation of MO molecules within 7.5 h.According to the analysis,the excellent SERS performance of the sandwich structures were attributed to the synergistic effect of LSPR effect of Au and adsorption effect of GO layer and filter membrane.In addition,the good photocatalytic activity was attributed to the photogenerated charge induced transfer mechanism during the sandwich structures.