In various aspects, the present disclosure is directed to methods and compositions for the simultaneous production of carbon nanotubes and hydrogen gas from lower hydrocarbon comprises methane, ethane, propane, butane, or a combination thereof utilizing the disclosed catalysts. In various aspects, the disclosure relates to methods for COx-free production of hydrogen with concomitant production of carbon nanotubes. Also disclosed are methods and compostions for selective base grown carbon nanotubes over a disclosed catalyst composition. In a further aspect, the disclosure relates to mono, bimetallic, and trimetallic catalysts comprising a 3d transition metal (e.g., Ni, Fe, Co, Mn, Cr, Mo, and combinations thereof) over a support material selected from a silica, an alumina, a zeolite, titatnium dioxide, and combinations thereof. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.