Photoelectrochemical (PEC) chloride oxidation reaction offers a green and sustainable approach for the synthesis of chlorinated chemicals, pesticides, pharmaceuticals/drugs, etc. However, until now, efficient PEC chloride activation remains highly challenging, primarily due to the lack of effective catalytically active reaction sites on the developed photoanodes. Herein, we construct a high-performance photoanode for PEC C-H chlorination by controllably embedding Pt single atoms onto positively charged TiO