Carbon Capture, Utilization, and Storage (CCUS) technology has gained widespread attention in recent years as a critical strategy to combat global climate change, particularly in achieving carbon neutrality goals. The Guangdong-Hong Kong-Macau Greater Bay Area (GBA), as one of China's most economically active regions, serves as a key engine for economic growth while also facing considerable carbon emission challenges. This study analyzes the industrial emission volume and geographical distribution of key emitting enterprises in the GBA, summarizes their technological processes and main carbon-emitting equipment, and provides scientific support for precise mitigation policies and low-carbon development. Based on data from 176 key emitting enterprises, the study reveals that Guangzhou and Dongguan host the largest number of such enterprises. Carbon emissions are primarily concentrated in the power sector, dominated by coal- and gas-fired power units, characterized by significant spatial dispersion and uneven distribution. Beyond the power sector, the paper industry has a high number of enterprises but lower emissions. Key facilities such as boilers, cogeneration systems, and production lines are predominantly located near tributaries rivers in Dongguan and Jiangmen. The building materials sector, primarily cement production, ranks as the second-largest emitter, with high-temperature kilns and grinding equipment, particularly rotary kilns and glass furnaces, as the main sources. The petrochemical and chemical sectors have fewer enterprises and lower emissions in the GBA, mainly located in suburban industrial clusters. Carbon emissions in the GBA exhibit distinct industry concentration and geographical distribution disparities. This study provides crucial data and theoretical insights for the development of targeted emission reduction strategies, optimization of source-sink matching, and the advancement of CCUS technologies in the region, particularly from the GBA to the northern South China Sea.

Hydrogen is emerging as a clean energy carrier in the global transition toward decarbonized energy systems. Leveraging established subsurface engineering expertise, underground hydrogen storage can be realized in salt caverns, depleted hydrocarbon reservoirs, and deep saline aquifers. However, the physicochemical characteristics of hydrogen including low viscosity, high diffusivity and strong chemical reactivity create unique challenges for its containment, transport and recovery from porous media. This review systematically analyzes the known interfacial and pore-scale mechanisms governing hydrogen migration, trapping and loss in heterogeneous reservoirs. The key processes comprise capillary trapping, molecular diffusion, interfacial reactions, and microbial activity. Interactions among hydrogen, brine and mineral surfaces are evaluated in terms of wettability, interfacial tension and pore connectivity, all of which directly influence storage efficiency and recovery performance. Advanced experimental methods such as nuclear magnetic resonance, microfluidics models, and X-ray computed tomography, combined with pore-scale simulations, are assessed for their ability to characterize multiphase flow and reactive transport behavior. Furthermore, the impact of operational factors like cushion gas composition, pressure cycling and injection-production strategies on storage integrity is discussed. Addressing these multi-physics and multi-scale challenges is essential for the safe and efficient implementation of underground hydrogen storage. Finally, this review identifies priority research directions aimed at improving mechanistic predictions and optimizing the operational management of hydrogen behavior in subsurface environments.

CO₂ sequestration into saline aquifers can significantly reduce atmospheric greenhouse gas concentrations, making it a key geological carbon storage technology for mitigating climate change and achieving carbon neutrality targets. However, current research predominantly focuses on reservoir saturation states, with limited understanding of dynamic mechanisms at the gas-liquid interface. In this study, microfluidic experiments were conducted at ambient temperature to investigate CO₂ drainage and imbibition under varying capillary numbers, incorporating the remobilization process driven by gas-water interphase mass transfer. Collectively, these three processes determine the temporal distribution of CO₂ and water phase saturations within the porous medium, thereby influencing the efficiency and long-term stability of CO₂ sequestration. With the increase of the capillary number, the sweep efficiency of CO₂ during drainage showed an upward trend, increasing to 54.71%. Moreover, this study provides an in-depth analysis of the distribution and morphological evolution of CO₂ under conditions where the aqueous phase is unsaturated. Results indicate that the asynchronous contraction of cluster interfaces results in a heterogeneous and dynamic dissolution process; the gas-water interface evolution of double-pore ganglia resembles the brine snap-off process; and singlet structures undergo shrinkage and deformation during the dissolution process. These findings elucidate the complex interactions between CO₂-water in porous media and underscore the critical roles of capillary forces and interfacial dynamics in geological carbon sequestration.