Dry reforming of methane (DRM) is an attractive reaction that consumes two major greenhouse gases while producing the industrially important components of syngas. In this study, various semiconductors were examined as light-harvesting support materials to promote catalytic DRM reaction under mild conditions. Among the metal-loaded catalysts, rhodium-loaded tantalum oxynitride (Rh/TaON) drove the DRM reaction even under visible light irradiation (>400 nm), and its activity exceeded the thermal catalyst limit. According to our spectroscopic analysis and the surface temperature measurement, the bandgap excitation of TaON dominantly promotes the DRM reaction in addition to its photo-thermal effect.