Preparation And Application Of Metal Oxide Nanocrystals Based On Surface Plasmon Resonance

With the excitation of incident light,collective oscillation of free electrons on the surface of the nanomaterials could lead to intensive light absorption and scattering,known widely as localized surface plasmon resonance(LSPR).Semiconductor tungsten oxide(WO3-x)nanomaterials with non-noble metal-based LSPR effect have been extended to electrocatalytic hydrogen evolution,light harvesting,photocatalysis and phototherapy due to their unique lattice structure and excellent optical and electrical properties.However,the current exploration,application and related mechanisms of the LSPR characteristics of the nanoscale WO3-x are still in the initial stage.In this paper,one-dimensional WO3-x nanorods with strong LSPR properties were prepared by a colloidal chemistry method.The intense LSPR characteristics significantly improved the catalytic performance of WO3-x for hydrogen production.Through the unique coupling structure design of WO3-x nanorods and Ni2P nanoparticles,the LSPR of WO3x also greatly enhanced the catalytic performance of Ni2P nanoparticles.The underlying mechanism for enhancing catalytic performance based on LSPR has also been further deeply analyzed.The research contents are as follows:1.WO2.72 nanorods with strong LSPR properties were successfully prepared under anhydrous and anaerobic conditions,using tungsten hexachloride as the tungsten source.They exhibited strong LSPR absorption in the visible near-infrared region,which could be tuned by the reaction conditions.By adjusting the relative proportion of oleic acid,the length of these nanorods can be modified.Compared with WO3,the band gap of WO2.72 containing oxygen vacancies increases significantly and the characteristic bandgap absorption shows a blue shift.The catalytic performance of WO2.72 nanorods based on LSPR is nearly 39 times higher than that of commercial WO3.What’s more,its hydrogen evolution rate under light conditions is 6.27 times higher than that of dark conditions.Abundant oxygen vacancies and strong LSPR absorption significantly promote the catalytic hydrogen production from aqueous ammonia borane solutions,due to its advantages of high electron transport rate,unique band structure and high crystallinity.2.Under the standard anhydrous and anaerobic conditions,a quasi-spherical Ni2P nanoparticle was successfully prepared by colloidal chemistry,with uniform morphology and an average diameter of about 9 nm.Oleylamine and octadeceneare were used as organic ligand-binding,while nickel acetylacetonate was utilized as the nickel source in the preparation.In addition,WO3-x/Ni2P nanohybrids with unique heterostructure were designed and fabricated.The catalytic hydrogen properties in ammonia borane of Ni2P nanoparticles and WO3-x/Ni2P nanohybrids both have been tested.Under visible light irradiation,this specially designed WO3-x/Ni2P nanohybrid showed 10～13 times enhancement of photocatalytic H2 evolution from ammonia borane comparing to the Ni2P alone.It could be ascribed to the efficient hot electron injection from plasmonic WO3-x nanorods to the surface of Ni2P nanoparticles to increase the reaction rate for hydrogen evolution under an enhanced electric field intensity by bilateral WO3-x nanorods.