<p>Photocatalytic conversion of solar energy represents a promising pathway toward renewable energy generation, with its efficiency fundamentally dependent on the generation, separation, and utilization of photogenerated charges within nanostructured photocatalysts. While substantial research has been devoted to understanding bulk charge generation and separation processes, the quantitative assessment of surface-reaching charges, which are crucial for driving redox reactions-remains a significant scientific challenge. In this review, we present the significant advancements achieved by our research group through the development and application of adsorbate (methanol) surface elementary reaction kinetic analysis method for quantifying surface-reaching photoholes in TiO₂-based photocatalysts. We systematically discuss its the theoretical foundations of this methodology and demonstrate its applications across various photocatalytic materials. Furthermore, we emphasize the critical role of surface and interface engineering in photocatalyst design for enhancing the concentration of surface-reaching charges. Finally, we provide a forward-looking perspective on emerging opportunities, including the potential for leveraging these insights to inform the rational design of advanced photocatalysts and the further development of surface elementary reaction kinetic analysis techniques to deepen our understanding of surface-reaching charge dynamics.</p>