多元金属氮氧化物LaTiO2N纳米结构制备及可见光全分解水研究

LaTiO2N is known as rich raw, 600 nm-light-sensitive, band energy levels suitable materials for water splitting. However, the water splitting efficiencies of this multiple metal oxynitride is yet limited by its bulk form. Moreover, the overall water splitting is still not realized through LaTiO2N, which is caused by its band structure and defects. In this proposal, we describe the multiple ions absorption and templating approaches to synthesize the LaTiO2N hollow nanostructure, which has controllable morphology, size and composition. We ultilize the non stoichiometric of La/Ti to tune the species and numbers of intrinsic defects and investigate the effect and regulate rule of the defects on the bandstructure of LaTiO2N. And, we develop the alkliane metal and transition metal doping in LaTiO2N to tune the energy level and numbers of defets. Furthermore, we use the surface treatment such as surface disorder modification to control the surface pinned energy level to suppress the surface recombination and promote the surface photocatalysis on LaTiO2N nanostructure. Based on these studies,the relationship between nanostructure morphology, size, defects, surface structure and photocatalytic properties of LaTiO2N nanostructures are clarified, and the relationship and tuning rules between light excitation, charge transport, surface reaction and band structure in LaTiO2N nanostructures are obtained to aim at improving the H2, O2 generation efficiency and realizing the overall water splitting of LaTiO2N. Finally the LaTiO2N based photocatalysts are expected to be obtained with 30% quantum efficiency for water splitting under visible light.

LaTiO2N,以其广泛的材料来源、600纳米的光响应、合适的氧化还原电位受到人们的广泛关注。然而现有的LaTiO2N均为块状材料，大大限制材料的光催化效率，并且能带结构和缺陷的问题不能实现可见光下的全水分解。本项目利用离子静电吸附和模板相结合的方法实现形貌、尺寸以及成分完全可控的以LaTiO2N为代表的多元金属氮氧化物纳米空心结构；利用非化学计量比调整本征点缺陷的类型和数量，研究其对材料能带结构的影响和调控规律；采用碱金属和过渡金属元素掺杂，调整缺陷能级数量和位置；利用表面无序化处理等手段控制表面钉扎能级，从而抑制光生载流子的表面复合。通过研究，阐明LaTiO2N纳米结构形貌、尺寸、缺陷和表面结构与光催化性能间的相互关系，掌握光激发、电荷输运、表面反应与能带结构间的关系与影响规律，以期达到提升量子转换效率并实现可见光下的全水分解，最终获得可见光量子效率不低于30%的光催化剂材料体系。

本项目利用离子静电吸附和模板相结合的方法实现形貌、尺寸以及成分完全可控的以LaTiO2N为代表的多元金属氮氧化物纳米空心结构；利用非化学.计量比调整本征点缺陷的类型和数量，研究其对材料能带结构的影响和调控规律；采用碱金属和过渡金属元素掺杂，调整缺陷能级数量和位置；利用表面无序化处理等手段控制表面钉扎能级，从而抑制光生载流子的表面复合。通过研究，阐明LaTiO2N纳米结构形貌、尺寸、缺陷和表面结构与光催化性能间的相互关系，掌握光激发、电荷输运、表面反应与能带结构间的关系与影响规律，提升了量子转换效率并实现可见光下的全水分解，获得(Ga1-xZnx)(N1-xOx)，H等离子处理LaTiO2N等可见光高量子效率的光催化剂材料体系。