Surface Plasmon Resonance Enhanced Hydrogen Evolution from Water with Graphitic Carbon Nitride Photocatalyst.

Solar energy can generate hydrogen via water splitting, which could decrease the environmental pollutions. During the photocatalytic hydrogen generation, some semiconductors can improve efficiencies. Recently, graphitic carbon nitride (g-C₃N₄) attracts interests due to visible light response. However, pristine g-C₃N₄ exhibits low photocatalytic activity. In this work, Au nanorods (Au NRs) were prepared via the colloidal seed-mediated approach, which assembled different structures by L-Cysteine (L-Cys). Meanwhile, the g-C₃N₄ was synthesized by means of thermal condensation of melamine. Based on this, we reports some photocatalysts by combining different Au NRs structures (random, aligned and aggregated) with g-C₃N₄. The hydrogen generation rates of different Au NR/g-C₃N₄ composites are 30.1 μmol h⁻¹ g⁻¹ (aligned), 44.5 μmol h⁻¹ g⁻¹ (random) and 46.9 μmol h⁻¹ g⁻¹ (aggregated), respectively. Interestingly, the hydrogen evolution rates are proportional to the surface plasmon resonance (SPR) enhancements of different Au NRs structures. The random and aggregated structures with some vertical Au NRs in contact with g-C₃N₄, can provide a better circuit for continuous flow of hot charge carriers. Nevertheless, horizontally aligned Au NRs reduce the Schottky barrier between Au NRs and g-C₃N₄, which enhances the back electrons and thus slow down the hydrogen generation. Our work reveals the effective Au/semiconductor photocatalysts to fabricate the vertically oriented Au NR layer contact with the semiconductor surface. This represents one of the future directions in this field. The preparation of different photocatalysts based on pristine g-C₃N₄ and aligned Au NR structures with g-C₃N₄. Our present work reveals the effective Au/semiconductor photocatalysts are to fabricate a highly vertically oriented Au NR layer with the ends of the Au NRs in direct contact with the semiconductor surface. This represents one of the future directions in this field. [ABSTRACT FROM AUTHOR]