<abstract abstract-type="toc"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <graphic position="anchor" id="ga" xlink:href="ark:/27927/pgj416m8bz" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" />To explore the photoelectrochemical efficiency of hematite as a photoanode, we comprehensively investigate the electronic structures of hematite doped with 4d transition-metal X (X = Y, Zr, Mo, Tc, Rh, and Ru) based on the density-functional theory (DFT).</p> </abstract>