A Co₃O₄/BiOBr heterojunction was synthesized via a facile one-step solvothermal method for highly selective photocatalytic CO₂ reduction. The optimized Co₃O₄/BiOBr-0.8 catalyst exhibited CO and CH₄ evolution rates of 112.2 and 5.5 μmol·g^-1·h^-1, respectively, representing 6.3-fold and 3.9-fold enhancements over pristine BiOBr. The heterojunction demonstrated broadened light absorption, enhanced photoelectrochemical activity, reduced charge-transfer resistance, and improved separation efficiency of photogenerated carriers (e^-/h⁺). These synergistic effects were attributed to the formation of a Z-scheme heterostructure, which facilitated solar energy utilization and electron reduction capacity while suppressing carrier recombination.