Unraveling the Plasmonic Effect of Au in Promoting\nPhotocatalytic H<sub>2</sub> Generation and Organic Synthesis

Incorporating plasmonic\nnanostructures into photocatalysts significantly\nenhances catalytic efficiency due to plasmonic effects. In this study,\nwe successfully developed a heterojunction between organic semiconductor\nzinc porphyrin (Zn-TCPP) and colloidal gold (Au) nanoparticles connected\nvia Au–O bonds. The formation of Au–O bonds between\nZn-TCPP and Au facilitates charge transfer efficiency by reducing\nthe Schottky barrier at the heterojunction interface. Finite-difference\ntime-domain simulations, in situ XPS measurements, and infrared thermal\nimaging confirm that the strong localized surface plasmon resonance\neffect of Au enhances the local electric field and photothermal effect,\npromoting the separation of electron–hole pairs in the Zn-TCPP/Au\nsample and improving the reaction kinetics. The optimal Zn-TCPP/Au-2%\ncomposite demonstrates an impressive H<sub>2</sub> generation rate\nof 1610 μmol·g<sup>–1</sup>·h<sup>–1</sup>, which is 2.7 and 8.6 times greater than the Zn-TCPP and TCPP samples,\nrespectively. Additionally,\nthe Zn-TCPP/Au-2% composite shows high efficiency in the C–N\ncoupling of benzylamine to imine, achieving a yield of 45.1 mmol·g<sup>–1</sup> in 24 h. This study provides a comprehensive understanding\nof how the plasmonic effect of Au enhances the activity of organic\nsemiconductor photocatalysts.