Cs3Bi2Br9 decorated with crystalline-amorphous Pd nanocubes as cocatalysts is reported to photocatalytically coproduce ca. 1400 μmol h-1 g-1 of H2 and benzaldehyde from the selective benzyl alcohol oxidation. This route offers an alternative for photocatalytic H2 generation using metal halide perovskites under mild conditions.