Using Raman spectroscopy to identify spectral features of and detect hydrogen peroxide‐potential application for Mars exploration

Abstract The Martian surface is oxidizing. An important oxidant, H 2 O 2 (hydrogen peroxide), has been detected in the Martian atmosphere and is supported even below the Martian surface. H 2 O 2 is an important target that can be used to better understand the Martian surface environment and explore extraterrestrial life and thus must be accurately detected and analyzed under Martian‐relevant temperature conditions. In this study, the Raman spectral features and the limit of detection (LOD) of H 2 O 2 were investigated for aqueous solutions and mud mixtures. The low‐temperature spectral features and UV decomposition characteristics of H 2 O 2 were also investigated because low temperatures and UV radiation are key environmental factors that can affect the existence of H 2 O 2 on the Martian surface. Our results show that H 2 O 2 has a remarkable Raman peak at 877 cm −1 , which is distinguishable from H 2 O and other mixed minerals, making it easy to detect with an LOD of 400 ± 50 ppm in an H 2 O 2 solution and 1666 ± 450 ppm in a kaolinite matrix (2000 ± 500 ppm in a gypsum matrix). There was no peak shift and only a certain degree of reduction in intensity for this peak in a H 2 O 2 solution under low temperature, even for frozen H 2 O 2 . Split peaks at ~228 cm −1 appeared after freezing H 2 O 2 , whereas there was no discernable split in the peak at ~3326 cm −1 below −60°C; however, the H 2 O peaks were splitted. The spectral features facilitate the detection and identification of H 2 O 2 on the Martian surface. In light of the Mars2020 and ExoMars rover missions, our study provides valuable information about the Raman detection of H 2 O 2 on Mars.