Devices and methods are disclosed for near unity absorption or near zero reflection of electromagnetic radiation over a wide range of wavelengths, omnidirectionally and that use the absorbed radiation to enhance the catalysis conversion of reactant chemicals to product chemicals of interest via the patterning of subwavelength metamaterial elements as a surface, or colloidal clusters of subwavelength particles as a suspension. The arrangements, dimensions, materials and geometries of the unit elements of the meta-surface or colloidal clusters may be selected to produce an effective refractive index lower than that of the refractive index of the comprising materials, such that the effective index approaches the index of the surrounding medium. Impedance matching, plasmonic modes between the metamaterial elements or cluster nanoparticles, ohmic material losses, and bandgap absorption may be combined to achieve broadband near-unity absorption and/or modulated thermal emission bands, enhancing the catalysis rates of gas, liquid and multi-phase chemical reactions.