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