Graphene-based Modulation On The Growth Of Urchin-like Na₂Ti₃O₇ Microspheres For Photothermally Enhanced Catalytic Performance

Sodium titanate,graphene and noble metal composites have become the focus of research because of their excellent catalytic properties.The excellent conductivity and large special surface area of graphene can promote the transfer of photoelectrons,thus inhibiting the recombination of carriers.Meanwhile,the precious metal gold nanoparticles can improve the utilization of visible light through local surface plasmon resonance（LSPR）.In this paper,RGO/Na₂Ti₃O₇ composites were prepared by the hydrothermal method,and their growth mechanism and photocatalytic performance were systematically studied,and the photocatalytic property of Au/RGO/Na₂Ti₃O₇ was further studied.The main research work is as follows:（1）RGO/Na₂Ti₃O₇ composites were prepared by the hydrothermal method.The RGO/Na₂Ti₃O₇ composites with different morphologies were obtained by controlling the hydrothermal time,the addition amount of GO and the lamellar size.Studies have shown that with the increase of hydrothermal time,sodium titanate has sea urchin-like microspheres gradually evolved into nanofibers,and the defects on the surface of GO and the functional groups as nucleation sites slowed down the maturation process of Ostwald,and the limited steric hindrance between adjacent GO tablets slowed down the growth of sodium titanate microspheres.（2）The as-prepared photoanode of RGO/Na₂Ti₃O₇ composite with different RGO contents was studied under visible light.Studies have shown that RGO/Na₂Ti₃O₇ can effectively improve the electronic transmission performance,50 wt%of RGO/Na₂Ti₃O₇ photocurrent density of the composite material can be up to 2.83 u A/cm² which is 13.6 times that of the photocurrent density of sodium titanate,and EIS value of 34.1Ωis less than ac impedance values of sodium titanate further evidence about the role of RGO.（3）The catalytic performance of RGO/Na₂Ti₃O₇ composite as a catalyst for hydrolyzing aminoborane（AB）to produce hydrogen was evaluated.RGO/Na₂Ti₃O₇ composites materials have a high photothermal conversion efficiency in visible light,among which the photothermal conversion efficiency of 66 wt%RGO/Na₂Ti₃O₇ is 69.6%.The high photothermal properties enhance the photocatalytic performance of hydrogen production by hydrolysis of AB.（4）Au nanoparticles were evenly dispersed on the surface of the RGO/Na₂Ti₃O₇ by the dipping method.The catalytic performance of the Au/RGO/Na₂Ti₃O₇ ternary catalyst was evaluated.The synergistic effect of close contact between the components of ternary isomers on the interface improved the catalytic performance of Au/RGO/Na₂Ti₃O₇,among which the photothermal performance played an important role in the catalytic process,and more importantly,Au had better stability under high-temperature catalysis.