Physics Department, University of South Florida, Tampa, FL 33620, USA.
Sensors (Basel). 2023 May 29;23(11):5171. doi: 10.3390/s23115171.
Despite its growing importance in the energy generation and storage industry, the detection of hydrogen in trace concentrations remains challenging, as established optical absorption methods are ineffective in probing homonuclear diatomics. Besides indirect detection approaches using, e.g., chemically sensitized microdevices, Raman scattering has shown promise as an alternative direct method of unambiguous hydrogen chemical fingerprinting. We investigated the suitability of feedback-assisted multipass spontaneous Raman scattering for this task and examined the precision with which hydrogen can be sensed at concentrations below 2 parts per million. A limit of detection of 60, 30, and 20 parts per billion was obtained at a pressure of 0.2 MPa in a 10-min-long, 120-min-long, and 720-min-long measurement, respectively, with the lowest concentration probed being 75 parts per billion. Various methods of signal extraction were compared, including asymmetric multi-peak fitting, which allowed the resolution of concentration steps of 50 parts per billion, determining the ambient air hydrogen concentration with an uncertainty level of 20 parts per billion.
尽管在能源发电和存储行业中越来越重要，但痕量氢的检测仍然具有挑战性，因为已有的光学吸收方法在探测同核双原子时效果不佳。除了使用化学敏化微器件等间接检测方法外，拉曼散射作为一种明确的氢化学指纹的替代直接检测方法显示出了前景。我们研究了反馈辅助多通自发拉曼散射在这一任务中的适用性，并检验了在低于 2 百万分比浓度下探测氢的精度。在 0.2 MPa 的压力下，分别在 10 分钟、120 分钟和 720 分钟的测量中，获得了 60、30 和 20 十亿分比的检测限，探测到的最低浓度为 75 十亿分比。比较了各种信号提取方法，包括不对称多峰拟合，它允许分辨率为 50 十亿分比的浓度步骤，确定环境空气中氢浓度的不确定度水平为 20 十亿分比。
