Development and Field Testing of Multi-Electrode Mixed Potential Electrochemical Sensors for Natural Gas-Hydrogen Mixture Emissions Monitoring

Transportation of hydrogen is one of the greatest hurdles to overcome in the development of a clean hydrogen economy [1]. A cost-effective solution to transportation of hydrogen is to mix it with natural gas (NG) and utilize current pipeline infrastructure for transportation [2]. However, hydrogen embrittlement, the higher diffusivity of H 2 , and the uncertain state of much of existing infrastructure makes leaks of H 2 an environmental and safety concern. Current NG leak detection technologies largely use optical sensors such as IR spectrometers that are incapable of detecting H 2 gas [3]. Mixed potential electrochemical sensors (MPES) are low-cost, robust devices capable of detecting a wide variety of gases [4], with the sensitivity and selectivity necessary for point source monitoring of natural gas leaks [5]. Multi-electrode MPES devices using Indium Tin Oxide, Au, and La 0.87 Sr 0.13 CrO 3 and Pt electrodes have previously successfully quantified CH 4 in natural gas at the 10-40 ppm level [5]. In this work, we demonstrated that the Au vs. Pt electrode has a low limit of detection of < 3 ppm for H 2 in an air atmosphere. We also performed field testing of H 2 emissions at CSU’s Methane Emissions Technology Evaluation Center (METEC) in both underground and above-ground emissions of H 2 and H 2 + natural gas mixes (Figure 1) with successful detection of H 2 at the ppm level. Finally, we evaluate the stability of the selectivity and sensitivity during prolonged exposure to H 2 and CH 4 . This work was supported by US Department of Energy Award DE-FE0031864. References: [1] R. Scita, P. P. Raimondi, and M. Noussan, Fondazione Eni Enrico Mattei (FEEM), 2020. Accessed: Dec. 01, 2023. Available: https://www.jstor.org/stable/resrep26335.5 [2] F. Öney, T. N. Veziro, and Z. Dülger, Int. J. Hydrog. Energy, vol. 19, no. 10, pp. 813–822, Oct. 1994, doi: 10.1016/0360-3199(94)90198-8. [3] T. Aldhafeeri, M.-K. Tran, R. Vrolyk, M. Pope, and M. Fowler, Inventions, vol. 5, no. 3, Art. no. 3, Sep. 2020, doi: 10.3390/inventions5030028. [4] F. H. Garzon, R. Mukundan, and E. L. Brosha, Solid State Ion., vol. 136–137, pp. 633–638, Nov. 2000, doi: 10.1016/S0167-2738(00)00348-9. [5] S. Halley, K. Ramaiyan, F. Garzon, and L. Tsui. Sens. Actuators B Chem., vol. 392, p. 134031, Oct. 2023, doi: 10.1016/j.snb.2023.134031. Figure 1. (a) Field test configuration of an above-ground emission with sampling lines drawing gas to IoT powered sensors. (b) Concentration measurements for H 2 and CH 4 captured on a Mixed Potential Sensor and an Aeris Mid-IR analyzer. Figure 1