Synthesis of highly crystallized particles of transition metal oxynitrides and construction of a photocatalytic system for visible light water splitting.

研究了一些d0型过渡金属氧氮化物作为光催化剂用于水的分解，以改善其性能。建立了助熔剂辅助氮化法制备氮氧化物颗粒的新途径。以NaC l或Na_2CO_3为助熔剂，可制得结晶度高、单分散的氧氮化物微粒。对于多组分氧氮化合物的合成，助熔剂的加入改善了组分的混合状态，使不同金属的掺杂成为可能。研究发现，掺杂价态低于母体阳离子的金属阳离子能有效地提高光催化析氢活性。这一趋势被发现适用于各种光催化剂。

Some d0-type transition metal oxynitrides were studied as photocatalyst for water cleavage to improve their performance. A new route to obtain oxynitride particles by flux assisted nitridation method was established. Highly crystallized and mono-disperse fine particles of oxyntrides were obtained by the addition of NaCl or Na_2CO_3 as a flux. Regarding the synthesis of multi-components-oxynitrides, the addition of flux resulted in the improvement of the mixing state of constituents, which enabled the doping of different metals. It was found that the doping of metal cations with lower valence than that of the parent cation was effective to enhance the photocatalytic activity of H_2 evolution. This tendency was found to be applicable to various photocatalysts.