Modified Solvothermal Strategy for Straightforward Synthesis of Cubic NaNbO3 Nanowires with Enhanced Photocatalytic H2 Evolution
Modified Solvothermal Strategy for Straightforward Synthesis of Cubic NaNbO3 Nanowires with Enhanced Photocatalytic H2 Evolution
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DOI：
10.1021/acs.jpcc.5b08018
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发表时间：
2015-11-19
影响因子：
3.7
通讯作者：
Li, Zhaosheng
中科院分区：
文献类型：
--
作者：
Gu, Qilin;Zhu, Kongjun;Li, Zhaosheng
为了进一步提高光催化析氢活性，通过改进的溶剂热策略成功合成了同时具有立方晶体结构和一维形貌的NaNbO3光催化剂。在使用乙二醇作为溶剂的合成过程中，提出在高压灭菌期间的温度波动来调节晶粒生长，而无需任何其他添加剂或煅烧。结果表明，在温度波动的条件下，溶剂的结构导向效应增强，有助于一维纳米结构的形成。否则，会产生严重聚集的不规则NaNbO3纳米颗粒。 0.5 wt% Pt 助催化剂在紫外光照射下样品的光催化析氢活性表明，NaNbO3 纳米线预计表现出 699 mu mol h(-1) g(-1) 的增强活性，接近 NaNbO3 纳米颗粒的两倍。 NaNbO3纳米线较高的光催化活性归因于其较大的比表面积、较高的化学纯度和强大的还原能力，这已通过基于晶体结构、价态、元素组成和能带结构的进一步表征和分析得到证实。改进的溶剂热策略提供了调节晶体生长的替代途径，可以有效地将独特的形貌与所需的晶体结构结合起来，从而提高光催化活性。
To further improve the photocatalytic H-2 evolution activity, NaNbO3 photocatalyts simultaneously possessing cubic crystal structure and 1D morphology have been successfully synthesized via a modified solvothermal strategy. During the process of synthesis employing ethylene glycol as solvent, a temperature fluctuation during the autoclaving period is proposed to regulate the grain growth without any other additives or calcinations. It is demonstrated that the structure-directing effect of the solvent is enhanced in the condition of the temperature fluctuation, contributing to the formation of 1D nanostructure. Otherwise, the irregular NaNbO3 nanoparticles with severe aggregation resulted. Photocatalytic H-2 evolution activities of samples under ultraviolet light irradiation with 0.5 wt % of Pt cocatalyst indicate that NaNbO3 nanowires expectedly exhibit an enhanced activity of 699 mu mol h(-1) g(-1), approaching twice that of NaNbO3 nanoparticles. The higher photocatalytic activity of NaNbO3 nanowires is attributed to their large specific surface area, high chemical purity, and powerful reduction ability, which have been confirmed by the further characterizations and analysis based on crystal structure, valence state, elemental composition, and energy band structure. The modified solvothermal strategy provides an alternative pathway to regulate the crystal growth, which can effectively integrate the unique morphology with desired crystalline structure toward increasing photocatalytic activity.