Supporting Information Doping of TiO 2 as a Tool to Optimize the Water Splitting Efficiencies of Titania-Hematite Photoanodes Darinka Primc,* a,b Mario Bärtsch, a Davide Barreca, c Giorgio Carraro, d Chiara Maccato, d Cinzia Sada, e Markus Niederberger a a Laboratory for Multifunctional Materials, Department of Materials, ETH Zurich, Vladimir- Prelog-Weg 5, 8093 Zurich, Switzerland. b Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom. c CNR-ICMATE and INSTM, Department of Chemistry, Padova University, 35131 Padova, Italy. d Department of Chemistry, Padova University and INSTM, 35131 Padova, Italy. e Department of Physics and Astronomy, Padova University, 35131 Padova, Italy Electronic Supplementary Material (ESI) for Sustainable Energy & Fuels. This journal is © The Royal Society of Chemistry 2017