S-scheme core-shell nanorods heterojunction of g-C₃N₄ quantum dots modified Er:WO₃/CdS towards visible light H₂ evolution via up-conversion fluorescence synergism

S-scheme core-shell nanorods heterojunction of Er:WO3/CdS/g-C3N4 QDs is fabricated via hydrothermalchemical-annealing method. Er:WO3/CdS/g-C3N4 QDs S-scheme heterojunction exhibits prominent enhanced photocatalytic HER (-1912.12 mu mol g-1 h-1) and degradation than WO3 (no HER/-5.0 folds), CdS (-20 folds/ -3.5 folds) and g-C3N4 QDs (-62 folds/-4.0 folds). There, the Er:WO3/CdS S-scheme heterojunction with carrier quenching and greater potential gradient can improve carrier separation, the CdS with higher absorption and Er:WO3 with near-infrared up-conversion fluorescence can increase solar efficiency, the g-C3N4 QDs with high quantum yield can increase carrier injection, all these can optimize the carrier efficiency, including transportation increasing, lifetime prolonging, recombination decreasing, and can be supported by the DFT. In addition, the CdS nanoparticles shell and g-C3N4 QDs can provide vast active sites, the core-shell nanorods structure can provide carrier pathway to inhibit photocorrosion, while maintaining good stability.