Committee Members' Information:

• Ph.D. Advisor Name: Bicheng Yan
• External Examiner Name: Hadi Nasrabadi
• Committee Chair Name: Yoji Kobayashi
• 4th Committee Member Name: Hussein Hoteit

• 5th Committee Member Name: Shuyu Sun

Carbon capture and storage (CCS) is considered to be a crucial strategy for controlling CO₂ emissions and combating climate change. Concurrently, Hydrogen has emerged as a promising clean and renewable energy resource to replace fossil fuels and facilitate the transition to a decarbonized society. In both technologies, fundamental understandings of the interfacial properties of the involved system is essential. Due to the difficulty associated with purification processes, the presence of impurities such as nitrogen can significantly influence the efficiency and safety of CO₂ storage. In particular, capillary pressure plays a key role in determining CO₂ migration, trapping, and storage security in deep saline aquifers and hydrocarbon reservoirs. Therefore, elucidating the effects of such impurities on capillarity is vital for accurate prediction and process optimization. In the context of hydrogen energy, cushion gases are commonly used to facilitate the withdrawal of hydrogen stored in saline aquifers and depleted oil and gas reservoirs. The bulk and interfacial properties of hydrogen–brine and cushion gas–brine systems critically affect the efficiency, economics, and environmental performance of subsurface hydrogen storage. In this dissertation, Molecular dynamics simulations are conducted to investigate interfacial properties in systems relevant to carbon capture and storage (CCS) and hydrogen storage, including N₂–oil–water mixtures, hydrogen–brine systems, and CO₂–brine–silica systems. The findings offer insights that support the design and optimization of efficient and environmentally sustainable CCS and hydrogen storage processes.