AI 中文总结
本文提出泵-泵光催化技术，通过超快测量区分光热与非热催化机制，明确氨分解反应中两种机制的时间尺度，发现非热机制可使H₂产量提升11倍，为光催化剂的原位诊断与活性优化提供方法。
AI 中文摘要
光可在等离激元纳米颗粒中同时诱导光热和非热催化活性，但这两种机制的程度、时间尺度和功效仍未明确。本文介绍了泵-泵光催化技术，这是一种超快激发关联光谱的改进技术，其中入射激光脉冲被分成两个空间和能量等效、具有可变时间延迟的脉冲。对于给定的反应和催化剂，可根据时间延迟、脉冲功率、激发波长、施加温度、反应物压力和脉冲不对称性，将光催化活性的时间敏感非线性增强与时间不敏感响应区分开来。通过这种方式，可在亚皮秒到纳秒的时间尺度上监测任何光催化剂的光热和非热活性的时间尺度，并可发现实现最佳化学反应性的条件。本文报道了使用Cu-Ru天线-反应器光催化剂对氨分解反应进行的超快测量：光热贡献对脉冲延迟几乎不敏感，而非热贡献在低激发强度、中等温度和亚纳秒时间尺度上最为明显；与脉冲重叠时相比，非线性非热机制可将H₂产量提高多达11倍。该技术可用于为任何化学反应的任何光催化剂提供前所未有的原位诊断和控制，最重要的是，这些测量使我们能够确定光的最佳分布，以最大化光催化活性。
英文摘要
Light can induce both photothermal and nonthermal catalytic activity in plasmonic nanoparticles, but the extent, timescale, and efficacy of these two mechanisms remain unresolved. Here we introduce pump-pump photocatalysis, an adaptation of ultrafast excitation correlation spectroscopy in which incident laser pulses are split into two spatially and energetically equivalent pulses separated by a variable time delay. For a given reaction and catalyst, time-sensitive nonlinear enhancements in photocatalytic activity may be distinguished from time-insensitive responses as a function of time delay, pulse power, excitation wavelength, applied temperature, reactant pressure, and pulse asymmetry. In this way, the timescales of photothermal and nonthermal activity of any photocatalyst may be monitored on sub picosecond to nanosecond timescales, and the conditions for optimal chemical reactivity may be discovered. Here we report ultrafast measurements of the ammonia decomposition reaction using a Cu-Ru antenna-reactor photocatalyst. Photothermal contributions exhibit little sensitivity to pulse delay, while nonthermal contributions are most apparent at low excitation intensity, moderate temperatures, and sub-nanosecond timescales. Here, nonlinear, nonthermal mechanisms enhance H$_2$ production by a factor up to eleven compared to when pulses overlap. This technique may be used to provide unprecedented \textit{in operando} diagnostics and control of any photocatalyst for any chemical reaction. Most importantly, these measurements allow us to ascertain the optimal distribution of light to maximize photocatalytic activity.
Comments17 pages, 4 figures
