<p>Reaction–diffusion processes, including Langmuir’s absorption kinetics and chemical reactions in porous catalysts, have been discussed. This model’s non-linear reaction–diffusion equation includes a non-linear term associated with Langmuir–Hinshelwood kinetics. Simple analytical expressions of the reactant concentration for all kinetic and adsorption parameters are reported using the hyperbolic function and the Akbari–Ganji method. The impact of different parameters on concentration is also discussed. The simple expression of the effectiveness factor is also obtained for general geometry and all reaction orders. A satisfactory agreement is observed when our theoretical results are compared with the simulation results. Our analytical results demonstrate a notable agreement with simulation outcomes, underscoring the effectiveness and reliability of our proposed methodology.</p>