P-type tin monoxide (SnO) decorated TiO2 nanoparticles have been synthesized by the powder atomic layer deposition (p-ALD) method in a fluidized bed reactor at 150-250 degrees C. Successful deposition of SnO on a TiO2 surface was realized using a precursor combination of Sn(dmamp)(2) and H2O as Sn source and reactant, respectively. Prepared SnO/TiO2 nanoparticles were characterized by XRF, XPS, XRD, and TEM-EDS. Formation of a p-SnO/n-TiO2 heterojunction resulted in improved photocatalytic methylene blue degradation performance compared to using a TiO2 photocatalyst, which might be attributed to facile separation of photo- induced electron-hole pairs as well as to increased UV/visible light absorption by adopting a narrow bandgap SnO.