Positive and negative charged stabilizing ligands, for example, ammonium surfactants and citrate, influence the catalytic activity of AuNPs greatly, due to their different electrostatic attraction ability with substrates. However, as for the more decisive factor in AuNPs catalyzed reactions, the free active surface sites of AuNPs influenced by different kinds of ammonium surfactants has not been studied yet. In this work, we prepared double chain and mono chain ammonium surfactants capped gold nanoparticles, DDAB-Au and CTAB-Au, and put them into the reduction reaction of uranine by NaBH₄. Compared to CTAB-Au, DDAB-Au favors the adsorption of BH₄⁻ and generation of metal hydride on the active sites. As a result, DDAB-Au catalyzed reduction of uranine could give shorter induction time. We attribute this phenomenon to a weaker binding affinity of DDAB to the active sites of AuNPs, resulting from the more flexible, less polar and low charge-to-molecular weight ratio properties of DDAB. Fast responding time is one of important criteria in analytical chemistry and sensor chemistry. With dramatic fluorescence changes, some DDAB-Au catalyzed reactions would facilitate the related studies in the fields of catalysis, analysis and biosensors.

带正电荷和带负电荷的稳定配体（例如铵表面活性剂和柠檬酸盐）由于其与底物的不同静电吸附能力，极大地影响了AuNPs的催化活性。然而，关于AuNPs催化反应中的决定性因素，尚未研究过不同种类的铵表面活性剂对AuNPs活性表面的影响。在这项工作中，我们制备了覆盖金纳米颗粒DDAB-Au和CTAB-Au的双链和单链铵表面活性剂，并将其用于NaBH ₄还原尿酸中。相比于CTAB金，DDAB金有利于BH的吸附₄ ^-在活性部位生成金属氢化物。结果，DDAB-Au催化的尿素还原可以缩短诱导时间。我们将此现象归因于DDAB对AuNPs活性位点的结合亲和力较弱，这是由于DDAB的弹性更大，极性更小和电荷与分子量之比较低。快速响应时间是分析化学和传感器化学的重要标准之一。随着荧光的剧烈变化，一些DDAB-Au催化的反应将促进催化，分析和生物传感器领域的相关研究。