【摘要】 pH时钟对于识别酸敏感物质和使用光谱技术阐明化学过程的机制至关重要。由于无机酸的快速酸化特性，有效控制其H⁺释放速率具有挑战性。此外，无机酸的强腐蚀性和有机酸的酸化速率随pH值的降低而减慢，进一步限制了它们在精细光谱分析中的适用性。因此，开发一种简单、安全、能够控制H⁺释放的酸化剂，并具有明确的识别窗口，对于光谱检测技术的进步至关重要。本研究提出氧化铌二氯化物（NbOCl₂）纳米片作为一种新型酸化剂，不仅可以调节H⁺释放速率，而且具有平滑的消光光谱，使其适用于监测酸响应行为。结果表明，NbOCl₂是构建pH时钟的理想平台。利用光谱动力学和时间分辨消光数据的一阶导数图像，量化了与消光光谱波长相关的关键因素。瞬态吸收结果进一步表明，NbOCl₂纳米片释放的H⁺降低了吸收，其载体动力学表现出明显的尺寸依赖性。这些特性表明NbOCl₂纳米片是酸化剂的理想候选者。更多还原

【Abstract】 The pH clock is critical for identifying acid-sensitive substances and elucidating the mechanisms of chemical processes using spectral techniques. Effectively controlling the rate of H⁺ release with inorganic acids is challenging due to their fast acidification property. In addition, the strong corrosiveness of inorganic acids and the slowing rate of acidification in organic acids with decreasing pH further limit their applicability in fine spectral analysis. Therefore, developing a simple, safe, acidifying agent capable of controlling H⁺ release with a well-defined identification window is crucial for advancing spectral detection technologies. This study presents niobium oxide dichloride（NbOCl₂） nanosheets as a novel acidifying agent that not only regulates the rate of H⁺ release but also has a smooth extinction spectrum, making it suitable for monitoring acid-responsive behavior. The results demonstrate that NbOCl₂ is an excellent platform for pH clocks. Using spectral dynamics and first derivative images of the time-resolved extinction data, we have quantified the key factors associated with the wavelength of the extinction spectrum. Transient absorption results further indicated that H⁺ released from NbOCl₂ nanosheets reduced absorption, with its carrier dynamics exhibiting pronounced size dependence. These properties suggest NbOCl₂ nanosheets to be an ideal candidate as an acidifying agent.更多还原