Advances and outlook for deep-sea hydrogen detection using in situ Raman spectroscopy
摘要
Hydrogen, a clean energy carrier with zero carbon emissions at the point of use and high gravimetric energy density, is widely viewed as an important component of the global energy transition. In particular, naturally occurring (“gold”) hydrogen has attracted increasing attention. The ocean covers more than 70% of Earth’s surface, and widespread seafloor occurrences of ultramafic rocks (peridotite and serpentinite) provide a key geological context for natural hydrogen generation. However, seafloor hydrogen detection has long been hindered by the extreme deep-sea environment and the high diffusivity of H2. In recent years, in situ Raman spectroscopy, a rapid and noncontact analytical technique, has progressively developed into a practical tool for in situ multiphase detection of hydrogen under deep-sea conditions. Here we review the development of deep-sea in situ Raman spectroscopic techniques and summarize representative applications in hydrogen-producing settings, including real-time quantification of dissolved H2 in the Manus hydrothermal field, measurements and annual flux estimates of dissolved H2 in the Kunlun hydrothermal pipe swarm, and in situ detection of gaseous H2 release at the Qianyuan vent field in the southern Okinawa Trough. Together, these studies demonstrate the capability of in situ Raman spectroscopy to detect hydrogen across phases and over a broad concentration range in complex seafloor environments. They also highlight the diversity of natural hydrogen-generating systems in the deep ocean. Looking ahead, deep-sea in situ Raman spectroscopy is expected to integrate more closely with submersible platforms, cabled seafloor observatory networks, and in situ seafloor experimental stations, enabling sustained monitoring and dynamic resource assessment of hydrogen-rich areas and thereby supporting large-scale exploration and potential development of seafloor “gold hydrogen” resources.