School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China.
Nanoscale. 2014 May 21;6(10):5458-66. doi: 10.1039/c4nr00005f.
Graphene aerogel materials have attracted increasing attention owing to their large specific surface area, high conductivity and electronic interactions. Here, we report for the first time a novel strategy for the synthesis of nitrogen-doped activated graphene aerogel/gold nanoparticles (N-doped AGA/GNs). First, the mixture of graphite oxide, 2,4,6-trihydroxybenzaldehyde, urea and potassium hydroxide was dispersed in water and subsequently heated to form a graphene oxide hydrogel. Then, the hydrogel was dried by freeze-drying and reduced by thermal annealing in an Ar/H2 environment in sequence. Finally, GNs were adsorbed on the surface of the N-doped AGA. The resulting N-doped AGA/GNs offers excellent electronic conductivity (2.8 × 10(3) S m(-1)), specific surface area (1258 m(2) g(-1)), well-defined 3D hierarchical porous structure and apparent heterogeneous electron transfer rate constant (40.78 ± 0.15 cm s(-1)), which are notably better than that of previous graphene aerogel materials. Moreover, the N-doped AGA/GNs was used as a new sensing material for the electrochemical detection of hydroquinone (HQ) and o-dihydroxybenzene (DHB). Owing to the greatly enhanced electron transfer and mass transport, the sensor displays ultrasensitive electrochemical response to HQ and DHB. Its differential pulse voltammetric peak current linearly increases with the increase of HQ and DHB in the range of 5.0 × 10(-8) to 1.8 × 10(-4) M for HQ and 1 × 10(-8) to 2.0 × 10(-4) M for DHB. The detection limit is 1.5 × 10(-8) M for HQ and 3.3 × 10(-9) M for DHB (S/N = 3). This method provides the advantage of sensitivity, repeatability and stability compared with other HQ and DHB sensors. The sensor has been successfully applied to detection of HQ and DHB in real water samples with the spiked recovery in the range of 96.8-103.2%. The study also provides a promising approach for the fabrication of various graphene aerogel materials with improved electrochemical performances, which can be potentially applied in biosensors, electrocatalysis, and energy storage/conversion devices.
石墨烯气凝胶材料因其大的比表面积、高导电性和电子相互作用而受到越来越多的关注。在这里，我们首次报道了一种合成氮掺杂活性石墨烯气凝胶/金纳米粒子（N-掺杂 AGA/GNs）的新策略。首先，将氧化石墨、2,4,6-三羟基苯甲醛、尿素和氢氧化钾的混合物分散在水中，然后加热形成氧化石墨烯水凝胶。然后，水凝胶依次通过冷冻干燥和在 Ar/H2 环境中热退火进行干燥。最后，GNs 被吸附在 N-掺杂 AGA 的表面上。所得的 N-掺杂 AGA/GNs 具有优异的导电性（2.8×10(3) S m(-1)）、比表面积（1258 m(2) g(-1)）、明确的 3D 分级多孔结构和明显的异质电子转移速率常数（40.78±0.15 cm s(-1)），明显优于以往的石墨烯气凝胶材料。此外，N-掺杂 AGA/GNs 被用作电化学检测对苯二酚（HQ）和邻二羟基苯（DHB）的新型传感材料。由于电子转移和质量传输得到了极大的增强，该传感器对 HQ 和 DHB 表现出超灵敏的电化学响应。其差分脉冲伏安峰电流随 HQ 和 DHB 在 5.0×10(-8)到 1.8×10(-4) M 范围内呈线性增加。HQ 的检测限为 1.5×10(-8) M，DHB 的检测限为 3.3×10(-9) M（S/N=3）。与其他 HQ 和 DHB 传感器相比，该方法具有灵敏度高、重复性好、稳定性好的优点。该传感器已成功应用于实际水样中 HQ 和 DHB 的检测，加标回收率在 96.8-103.2%范围内。该研究还为制备具有改进电化学性能的各种石墨烯气凝胶材料提供了一种有前途的方法，这些材料可应用于生物传感器、电催化和储能/转换器件。
