Objective The formation of hydrogen atoms on the surface of hydrogen pipeline steel serves as the critical link between the external hydrogen environment and internal hydrogen-induced damage. While existing research heavily focuses on hydrogen diffusion, hydrogen trapping, and macroscopic mechanical property degradation, systematic reviews regarding the dissociative adsorption of hydrogen on pipeline steel surfaces remain insufficient, hindering direct support for the safety evaluation of in-service hydrogen pipelines.

Methods Centering on the initial process of the dissociative adsorption of hydrogen, recent research regarding gaseous hydrogen embrittlement and hydrogen behavior in pipeline steel was summarized across three dimensions: theoretical foundations, experimental testing, and numerical simulations. The application scopes of multiple methodologies—including surface characterization, hydrogen permeation testing, density functional theory, ab initio molecular dynamics, and the finite element method—were systematically compared. Furthermore, influencing factors such as surface states, oxide films, impurity gases, alloying elements, temperature, and stress were integrated into a unified analytical framework.

Results Statistical analysis indicated that in the field of gaseous hydrogen embrittlement, studies on macroscopic mechanical properties and hydrogen embrittlement mechanisms accounted for approximately 72％, those on hydrogen diffusion in steel accounted for roughly 15％, and only around 8％ directly addressed surface dissociative adsorption—revealing insufficient research on this initial process. Comparative analysis of typical numerical simulation methods revealed that density functional theory was applicable to analyzing stable adsorption sites, adsorption energy, and dissociation energy barriers at a scale of 0.1–10.0 nm. Ab initio molecular dynamics described dynamic interfacial processes at finite temperatures for scales of 0.1–20.0 nm, though it was limited by system size and time scale. The finite element method could reach micrometer scales and even component scales, but it relied on atomic-scale input parameters. Experimental results further demonstrated that surface roughness, grain boundaries, dislocation emergences, and inclusion interfaces increased local active site density. While oxide films and passive layers generally hindered hydrogen ingress, gas impurities introduced distinct chemical behaviors: O₂ and CO primarily induced competitive adsorption and surface poisoning, CO₂ exhibited environment-dependent characteristics, and H₂S tended to facilitate the ingress of atomic hydrogen into the steel matrix.

Conclusion The dissociative adsorption of hydrogen on pipeline steel surfaces should not be regarded as an isolated surface reaction, but rather as the starting point of the entire degradation sequence: surface hydrogen generation – interfacial hydrogen ingress – bulk hydrogen diffusion – hydrogen trapping and enrichment – damage evolution. Future research should focus on in-situ characterization under high-pressure gas phases, standardized gaseous hydrogen permeation testing, and multi-scale coupling models to provide quantitative benchmarks for material selection, gas quality management, and the safety evaluation of in-service hydrogen pipelines.