Preparation Of Multiple Metal Nanomaterials And Their Application In Photocatalysis And Photoelectrocatalysis

With the aggravation of the energy crisis and the worsening of environment,exploring the new type of energy source to replace fossil fuel and developing a new energy structure is becoming more and more urgent.Solar water splitting enlightens us human as a promising solution to the problem we faced in energy and environment simultaneously by storing the solar energy as the hydrogen energy,while preventing greenhouse gas emission.The greatest challenge in converting the solar energy to chemical energy is the rather low performance of the photocatalyst.Here,we enhanced speed of solar water splitting through controlling the morphology of the photocatalyst and designing the rational structures composition.Firstly,we designed and synthesized a type-II hetero-junction dual shell hollow spheres loaded with spatially separated co-catalyst,which provides a suitable way to form synergy between the built-in electric field and rapid export charges（activity sites）and prevents the reverse reaction of water splitting.Its hydrogen evolution rate is 2120μmol g^-1 h^-1 under 100 mW cm^-2 visible light irradiation,which is over 540 times higher than that of TiO₂/CdS double-shelled hollow spheres under the same conditions.Secondly,we synthesized the LaTiO₂N nanowires through electrospinning method and used them as the photoanode material.Furthermore,we improved the photo current of photoanode through changing the synthesis of the LaTiO₂N nanowires and the fabrication process of photoanode,which paves the way for the high performance photocatalyst through controlling morphology and designing composite structure.Thirdly,we synthesized the PrTiO₂N nanowires and employed them as the photoanode material through the same method we developed before.Besides,we also synthesized the Co₃O₄nanoparticles and loaded them on the PrTiO₂N nanowires photo anode.The photo current of the photoanode increased from 0.8 mA cm^-1 to 2.9 mA cm^-1 after loaded with the Co₃O₄.Multiple method was employed to illustrate the mechanism of the improvement.A p-n junction formed between the Co₃O₄ nanoparticles and PrTiO₂N nanowires,meanwhile the Co₃O₄ also acted as the cocatalyst to improve the surface reaction.At last,we synthesized uniform LaTiO₂N nanotubes with smooth and compact wall through a simple method.By studying the formation process of the above-mentioned LaTiO₂N nanotubes,we deduced the formation mechanism which was later extended to the synthesis of CeTiO₂N and PrTiO₂N nanotubes.Subsequently,we fabricated the LaTiO₂N nanotubes photoanode.The 5 nm CoFe₂O₄ nanoparticles were loaded on LaTiO₂N nanotubes,which resulted in a significant improve in the speed of photoelectric water splitting.