DSA-type　Ti/RuxSn1-xO2　electrodes　were　prepared　by　thermal　decomposition　method　as　photoelectrocatalysts　(PECs)　and　extensively　characterized　by　various　sophisticated　techniques.　First-principles　calculations　was　employed　to　study　the　effects　of　Ru　content　on　the　electronic　structures　of　the　RuxSn1-xO2　coatings.　The　photoelectric-synergistic　catalytic　activity　of　the　Ti/RuxSn1-xO2　electrodes　was　evaluated　for　the　degradation　of　methyl　orange　(MO)　in　aqueous　solution.　The　results　show　that　the　RuO2-SnO2　solid　solution　could　be　formed.　The　band　gaps　of　the　RuxSn1-xO2　coatings　gradually　decreased　and　eventually　turned　into　metallic　conductivity　with　the　increase　of　ruthenium　content.　As　a　PEC　electrode,　reducing　band　gap　is　helpful　to　improve　electronic　conductivity　and　the　electrocatalytic　activity,　but　not　always　advantageous　to　increase　the　photocatalytic　activity.　Because　too　narrow　band　gap　will　sacrifice　the　photogenerated　charge　carriers　and　thus　reduce　photocatalytic　activity　of　the　electrode.　In　our　experiments,　the　rate　constant　of　Ti/Ru0.05Sn0.95O2　electrode　increased　with　increasing　Ru　content　and　exhibited　the　maximum　rate　for　5%　Ru　loading.　The　stability　test　showed　the　photoelectrocatalytic　activity　of　the　Ti/Ru0.05Sn0.95O2　electrode　almost　had　no　attenuation　after　100　h　photoelectrolysis,　revealing　that　this　electrode　has　good　long-term　stability.　(C)　2017　Elsevier　B.V.　All　rights　reserved.