Graphene Nanosheets as a Platform for the 2D Ordering of Metal Oxide Nanoparticles: Mesoporous 2D Aggregate of Anatase TiO2 Nanoparticles with Improved Electrode Performance
Graphene Nanosheets as a Platform for the 2D Ordering of Metal Oxide Nanoparticles: Mesoporous 2D Aggregate of Anatase TiO2 Nanoparticles with Improved Electrode Performance
复制标题
DOI：
10.1002/chem.201200551
复制
发表时间：
2012-10-01
影响因子：
4.3
通讯作者：
Hwang, Seong-Ju
中科院分区：
文献类型：
--
作者：
Lee, Jang Mee;Kim, In Young;Hwang, Seong-Ju
石墨烯纳米片已成功应用于金属氧化物纳米颗粒二维排序的有效平台。通过在高温下对均匀杂化的层状钛还原氧化石墨烯 (RGO) 纳米复合材料进行热处理，合成了锐钛矿型 TiO2 纳米粒子的介孔二维聚集体。前体层状钛酸酯RGO纳米复合材料是通过阴离子RGO纳米片和阳离子TiO2纳米溶胶的自组装制备的。将所制备的层状钛酸盐RGO纳米复合材料在500℃下煅烧，导致层状钛酸盐纳米板发生结构和形态变化，转变为锐钛矿型TiO2纳米颗粒，而RGO纳米片没有发生明显的改性。将加热温度提高到 600°C 会消除 RGO 成分，从而形成不含 RGO 的 TiO2 纳米粒子的片状多孔聚集体。在 500700 摄氏度下煅烧的纳米复合材料显示出作为锂离子电池负极的有前途的功能。在目前的煅烧衍生物中，在 600℃ 下煅烧获得的 TiO2 纳米粒子的二维片状聚集体在所应用的所有电流密度条件下具有最大的比放电容量和良好的容量保持率。在600℃下煅烧的纳米复合材料如此优异的电极性能归因于二氧化钛晶体结构和晶体形态稳定性的提高以及通过扩大介孔来增强Li + 离子传输。目前的研究结果清楚地证明了 RGO 纳米片作为具有改善的电极性能的金属氧化物纳米颗粒二维有序超结构平台的有用性。
Graphene nanosheets are successfully applied as an effective platform for the 2D ordering of metal oxide nanoparticles. Mesoporous 2D aggregates of anatase TiO2 nanoparticles are synthesized by the heat treatment of the uniformly hybridized nanocomposite of layered titanatereduced graphene oxide (RGO) at elevated temperatures. The precursor layered titanateRGO nanocomposite is prepared by self-assembly of anionic RGO nanosheets and cationic TiO2 nanosols. The calcination of the as-prepared layered titanateRGO nanocomposite at 500?degrees C induces a structural and morphological change of layered titanate nanoplates into anatase TiO2 nanoparticles without significant modification of the RGO nanosheet. Increasing the heating temperature to 600?degrees C gives rise to elimination of the RGO component, leading to the formation of sheetlike porous aggregates of RGO-free TiO2 nanoparticles. The nanocomposites calcined at 500700 degrees C display promising functionality as negative electrodes for lithium ion batteries. Among the present calcined derivatives, the 2D sheet-shaped aggregate of TiO2 nanoparticles obtained from calcination at 600?degrees C delivers the greatest specific discharge capacity with good capacity retention for all current density conditions applied. Such superior electrode performance of the nanocomposite calcined at 600?degrees C is attributable both to the improved stability of the crystal structure and crystal morphology of titania and to the enhancement of Li+ ion transport through the enlargement of mesopores. The present findings clearly demonstrate the usefulness of RGO nanosheets as a platform for 2D-ordered superstructures of metal oxide nanoparticles with improved electrode performance.