Hydride abstraction by triphenylcarbenium cations in the presence of terminal alkynes and alkenes results in hydrosilylation at room temperature on hydride-terminated porous silicon surfaces, leading to alkenyl- and alkyl-terminated surfaces, respectively. A wide range of surface terminations are possible as the reaction conditions tolerate a variety of functional groups. Silicon-carbon bond formation is substantiated by Fourier transform infrared and C-13 solid-state NMR spectroscopies, in addition to chemical and stability studies. Generation of an energetic surface silicon-based positive charge is thus a viable route to the formation of silicon-carbon bonds via hydrosilylation, a step previously postulated for the mechanism of exciton-mediated hydrosilylation on photoluminescent nanocrystalline silicon.