Photocatalytic reactions powered by solar energy are essential for capitalizing on renewable solar resources. However, efficiently utilizing the entire sunlight spectrum for reactions with high activation energy, such as alkane dehydrogenation, poses a major challenge in catalyst design. In this research, we propose a surface modification strategy that generates abundant interfacial sites on the TiN surface while preserving strong light absorption, promoting interfacial electron-hole recombination, and supporting catalytic reactions across the full spectrum. Through a combination of spectroscopic, theoretical, and experimental investigations, we demonstrate the effectiveness of this catalyst design in enhancing solar energy utilization. We have successfully developed a SrTiO₃/SrO_x-TiN catalyst that significantly enhances the activity of non-oxidative ethane dehydrogenation by 11.7-fold under solar photocatalysis. The strategy revealed in this work, which involves constructing abundant reaction sites with enhanced interfacial electron-hole recombination, is vital for developing advanced heterogeneous solar photocatalytic systems.