Although gold nanorods (GNRs) have been produced with different dimensions and aspect ratios, the current synthesis methods through seed-mediated growth are far from ideal, for instance, the quality (rod yield) and the quantity (gold conversion) cannot be simultaneously satisfied. More critically, there is no molecular level understanding of the growth mechanism. Here, we solved the problem by employing the stoichiometric ratio of reactants and tuning the reactivity of the reductant through adjusting the initial pH value of the growth solution to achieve both good quality and high quantity simultaneously. We also extended our strategy to other enols besides ascorbic acid, such as phenolic compounds, and found that the optimal pH for GNRs synthesis depends on the structure of the individual compound. The mechanistic insight greatly enriches the toolbox of reductants for GNRs growth and makes it possible to synthesize GNRs at both acidic and basic conditions. An interesting phenomenon is that for most of the phenolic compounds we tested, the morphology of the final products follows the same sphere-rod-sphere trend as the initial pH value of the reaction increases, whether it is under acidic or basic conditions, which cannot be explained by any previously proposed mechanism. The effect of pH is mainly attributed to the regulation of the reduction potential of the reductants, and thus the reaction rate. A model has been proposed to explain the dependence of anisotropic growth of GNRs on the concentration gradient of reactants around the seeds, which is decided by both the reaction rate and diffusion rate.

尽管已生产出具有不同尺寸和纵横比的金纳米棒（GNR），但是目前通过种子介导的生长方法合成的纳米方法远非理想，例如，不能同时满足质量（棒产量）和数量（金转化率）的要求。 。更关键的是，没有分子水平的了解其生长机理。在这里，我们通过使用反应物的化学计量比并通过调节生长溶液的初始pH值来调节还原剂的反应性来解决问题，从而同时实现了高质量和高产量。我们还将策略扩展到除抗坏血酸以外的其他烯醇，例如酚类化合物，并发现合成GNR的最佳pH值取决于单个化合物的结构。机械学的见解极大地丰富了还原剂用于GNRs生长的工具箱，并使得在酸性和碱性条件下合成GNRs成为可能。一个有趣的现象是，对于我们测试的大多数酚类化合物，最终产物的形态都遵循相同的球杆-球状趋势，因为反应的初始pH值增加了，无论是在酸性还是碱性条件下，都无法做到。可以通过任何先前提出的机制进行解释。pH值的影响主要归因于还原剂还原电位的调节，进而是反应速率的调节。已经提出了一个模型来解释GNRs的各向异性生长对种子周围反应物浓度梯度的依赖性，而该浓度梯度由反应速率和扩散速率共同决定。