Simultaneous enhancements in photon absorption and charge transport of bismuth vanadate photoanodes for solar water splitting

N-Type bismuth vanadate has been identified as one of the most promising photoanodes for use in a water-splitting photoelectrochemical cell. The major limitation of BiVO4 is its relatively wide bandgap (∼2.5 eV), which fundamentally limits its solar-to-hydrogen conversion efficiency. Here we show that annealing nanoporous bismuth vanadate electrodes at 350 °C under nitrogen flow can result in nitrogen doping and generation of oxygen vacancies. This gentle nitrogen treatment not only effectively reduces the bandgap by ∼0.2 eV but also increases the majority carrier density and mobility, enhancing electron-hole separation. The effect of nitrogen incorporation and oxygen vacancies on the electronic band structure…

• NS
  National Science Foundation

  Awards: 1305124, CHE-1305124
• NE
  National Energy Research Scientific Computing Center
• DO
  Division of Chemistry

  Awards: 1305124, CHE-1305124