The present investigation examines an innovative method for improving the efficiency of thermal separation of binary gas mixtures in a parallel plate configuration. The Direct Simulation Monte Carlo (DSMC) approach was employed for precisely modeling flow in rarefied regimes at micro-scales. The study explores separating a 50%-50% heliumxenon mixture between two plates, highlighting the potential of using specular and diffusive surfaces to generate effective separation flows. We investigated the influence of Knudsen numbers (Kn), specifically Kn=0.05, 0.1, 0.5, and 1, by analyzing temperature, velocity, and molar fraction distributions. In this configuration, the temperature gradient is 600 K, with distinct thermal properties on the upper and lower walls, the latter equally divided between specular and diffusive surfaces. Key aspects include enhancement of flow field dynamics and species separation efficiency through non-mechanical geometries leveraging ambient heat and surface property variation. Observations reveal that helium accumulates along the hot wall while xenon collects along the cold wall due to opposing diffusive velocities.