Nanostructured BaTiO3/Cu2O heterojunction with improved photoelectrochemical activity for H2 evolution: Experimental and first-principles analysis

Nanostructured BaTiO3/Cu2O heterojunction electrodes with varying thickness of Cu2O thin films were synthesized using spray deposition of porous cuprous oxide films onto the surface of spin coated nanostructured thin films of BaTiO3. First-principles based density functional theory calculations have been done for the first time on the band offsets of BaTiO3/Cu2O heterojunction interface and effective mass of electron and hole for bulk BaTiO3 and Cu2O, exhibited better separation of the photogenerated charge carriers at the BaTiO3/Cu2O interface. Experimental results on photoelectrochemical activity of BaTiO3/Cu2O heterojunction in the photoelectrochemical cell for water splitting reaction validate the theoretical results. Maximum photocurrent density value of 1.44 mA/cm2 at 0.95 V/SCE was observed for BaTiO3/Cu2O heterojunction photoelectrode with 442 nm thickness. Photo-generated charge carriers apparently transfer more easily in BaTiO3/Cu2O heterojunction than that in pristine Cu2O and BaTiO3.