Photocatalytic activity of metal-ceramic composites synthesized by self-propagating high-temperature synthesis (SHS) is investigated in the processes of degradation of diclofenac (DCF). Optical properties of the composites were studied, and the band gaps of ceramic matrix semiconducting components were calculated from the absorbance spectra. The effect of the phase composition, UV irradiation duration, the nature and quantity of the activator (H2C2O4 and H2O2) on the degree of oxidation destruction was investigated. The best catalytic performance (98–99 % DCF degradation) was achieved with the combination of heterogeneous boron nitride and SiAlON based composites and a homogeneous photo-Fenton system. However, DCF decomposition with a minimum number of intermediates was achieved using boron nitride-based composites.