Investigation On Laser-based Synthesis In Solution And Properties Of Metal Chalcogenide Nanomaterials

Metal chalcogenide nanomaterials have been widely used in photodetector,photodegration,electrocatalysis fields,due to their unique physical and chemical properties.The exploration of new synthesis strategy is critical to metal chalcogenide materials.Pulsed laser ablation in liquid is a green,simple and efficient technique for material synthesis.In this dissertation,this work is mainly focused on metal chalcogenide materials(such as CdS,CdTe,NiO/NiFe-LDH,etc.).CdS,CdTe nanowires and NiO/NiFe-LDH complex nanomaterials have been acquired by laser ablation in liquid,and tested their photoresponse and electrocatalysis performance.1.CdS,CdTe and CdSeTe nanowires on the silicon substrate were synthesized through LAC technique in liquid medium at room temperature for the first time.And the influence factors for the successful fabrication of nanowires were investigated in detail.Experiments showed that the reactivity of precursor was critical to the successful fabrication of nanowires.Besides,the concentration of precursor,laser energy density and laser ablation time determined the quality of the nanowires.The photoresponse performance of as-obtained CdS nanowires were tested.The result showed that the electrical current under white light illumination was more than 6 times higher than in dark at a bias voltage of 2.0 V.The photocurrent response to on-off cycles at a fixed voltage of 1.0 V showed clearly that the photocurrent remained relatively stationary,indicating good reversibility and stability of the photo detector device.2.CdTe NWAs on the silicon substrate were acquired by LADA technology and the CdTe NWAs growth mechanism was in-depth exploration for the first time.In the absorption stage,Au catalysts were heated using a pulsed laser and absorbed Cd atoms to produce larger AuCdx NPs.In the desorption stage,the AuCdx NPs were heated using the laser again and desorbed Cd atoms which react with Te atoms to grow CdTe NWAs.The product of the LDAD technique was not random NWs but regular NWAs which standed upright on the substrate and possess a monocrystal structure,high density and uniform distribution.Compared with the photocurrent in the dark at a bias voltage of-1.0 V,a huge increase(600%)in electrical current was observed under white light illumination.3.NiO/NiFe-LDH composite nanomaterials were gained by laser ablation in liquid.The study found that the amount of NiFe-LDH in products increased with the Ni atom ratio increasing in initial alloy target.We investigated the electrocatalytic OER activity of NiO/NiFe-LDH composite nanomaterials in alkalin solutions(1 M KOH).The overpotential at a current density of 10 mA/cm~2 was only 270 mV vs RHE.According to the stability test,the NiO/NiFe-LDH composite nanomaterials loading on carbon fiber exhibits good durability under the current density of 10 mA/cm~2(potential differentce of 6 mV at 10 h).4.Uniform 3D porous CdS nanoflowers were formed through hydrothermal process under the cationic ligand protection effect and the template effect of CTAB.The photodegration RhB performance of 3D porous CdS nanoflowers was stuied and the results showed that the as-prepared products exhibited good photocatalytic activities and high photo stability with the protection of CTAB.