纳米片自组装的(BiO)_2CO_3单分散微米绒球的绿色可控合成及其光催化性能（英文）

Facile Green Synthesis of Highly Monodisperse Bismuth Subcarbonate Micropompons Self-assembled by Nanosheets:Improved Photocatalytic Performance

采用水为溶剂,Bi(NO_3)_3?5H_2O为Bi源,C_6H_5Na_3O_7?2H_2O(TCD)为配体构筑了前驱配合物Bi-TCD,通过配合物分解实现了由纳米片自组装的碳酸氧铋(BS)微米绒球的绿色可控合成,例如,BS的结构和形貌可经由改变反应物浓度和反应时间来调控。我们发现,一方面,TCD的配位作用可致BiO^+离子缓慢释出从而调控BS的形成速率;另一方面,尿素在BS材料的形成过程中起碳源、碱源、形貌调控剂和晶体成长控制剂的多重作用,通过调控尿素的浓度制备了三种分别沿着[001]、[110]和[013]优势生长方向的BS晶体。这种合成方法成本低,不需要有机溶剂、模板、表面活性剂、高温和很长的反应时间;产物分散性好;产率高;且拥有可控的形貌和优势生长方向。特别是由纳米片自组装的BS微米绒球对罗丹明B展现出优异的光催化性能。我们相信当前工作将是绿色可控合成和无机微纳材料应用方面的一个重要进展。

This work reports a controlled green synthesis of highly monodisperse bismuth subcarbonate （BS） micropompons self-assembled by nanosheets using a simple and facile hydrothermal route in which deionized water, bismuth nitrate pentahydrate （BNP）, and urea were used as the solvent, bismuth source, and carbon source respectively. Trisodium citrate dihydrate （TCD） was used as a coordination agent to fabricate a complex precursor. The structure and morphology of the BS materials can be finely modulated by adjusting the initial concentration ratios of the reactants or the reaction time. The presence of TCD decreased the formation rate of BS due to a direct competitive interaction for the BiO＋ ions between a coordination equilibrium and a precipitation equilibrium. Urea played a crucial role （e.g., carbon source, alkaline source, morphology control agent, and crystal growth control agent） in the formation of the BS microstructures. We obtained three kinds of BS crystals with preferred orientations along [001], [110], and [013] by adjusting the concentration of urea. Our synthesis approach has the advantages of low cost, high reaction yields, monodisperse particles, controlled morphologies and orientations, and not requiring the use of organic solvents, templates, surfactants, hightemperatures, and long reaction times. Particularly, when compared with those reported by other investigators, the micropompon material exhibited improved photocatalytic performance for Rhodamine B due to a unique microstructure （large specific surface area, high efficiency of photoelectric conversion, small interfacial charge- transfer resistance, and active {001} exposed facets）. These results indicate a major advance in the controlled green synthesis and the application of inorganic micro- and nano-materials.