Fast-growing energy demands and the depletion of conventional fuel resources such as crude oil and coal are among the most recent issues treating the world\\\\\\\\\\\\\\\'s energy security. Gaseous energy carriers such as methane and hydrogen seem promising abundant alternative fuel resources. However, these gasses\\\\\\\\\\\\\\\' low volumetric energy density makes their storage energy and cost extensive. High-pressure gas storage inside porous materials such as carbons is considered one way to tackle the low energy density problem of gasses. This review article represents the state-of-the-art with a focus on what has been done to improve/enhance the gas storage capacity of traditional and novel carbon-based structures. Since the fabrication condition of carbonaceous matters can significantly affect their properties (porosity and packing density) and their gas adsorption performance, we systematically analysed the recent experimental and theoretical advances in the design and preparation of these materials. We review various synthesis strategies of amorphous and nano allotrope carbons, emphasising their methane and hydrogen adsorption performance. A critical assessment was conducted to connect the structural properties of carbonaceous adsorbents and their gas adsorption capacity.

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