Abstract: The use of catalysts under high-temperature steam conditions enhances oil shale pyrolysis efficiency and increases the permeability of flow channels, serving as a prerequisite for the industrialization of in-situ thermal extraction of oil shale. An experimental approach was used to investigate how catalysts affect microscopic pore-structure parameters and the extent of damage to oil shale during high-temperature steam pyrolysis. We independently constructed the oil shale pyrolysis experimental system, and results show that adsorption capacity, specific surface area, pore volume, and mechanical properties vary with catalyst concentration. The main conclusions are as follows: (1) The mass loss rate of oil shale treated with MnSO4 and CrCl3 solutions increases significantly relative to untreated shale, by up to 6.9% and 4.7%, respectively. As catalyst concentration increases, oil shale pores become predominantly small mesoporous (2−10 nm); the Barrett–Joyner–Halenda (BJH) pore volume and specific surface area increase. Owing to the predominance of small mesopores, the average pore size initially increases and then decreases. The fractal dimension decreases. (3) Catalytic pyrolysis reduces the elastic modulus of oil shale to varying degrees, with greater deterioration at higher catalyst concentrations. The maximum decreases in elastic modulus are 2.43 GPa and 3.35 GPa, respectively, and the corresponding peak energy-storage densities are below 0.12 MJ/m3. Higher catalyst concentrations lead to more extensive pyrolysis, with weaker energy absorption, storage, and release, and greater energy consumption

Key words: oil shale, catalyst, pore structure, damage deterioration