Wavelength dependent luminescence decay kinetics in ‘quantum-confined’ g-C3N4 nanosheets exhibiting high photocatalytic efficiency upon plasmonic coupling
| Autor: | Chathakudath P. Vinod, Raj Sekhar Roy, Ujjal K. Gautam, Arijit K. De, Samita Mishra, Yuvraj Vaishnav, Lipipuspa Sahoo, Sanjit Mondal |
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| Rok vydání: | 2020 |
| Předmět: |
Photoluminescence
Nanocomposite Materials science Renewable Energy Sustainability and the Environment Nanoparticle 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences Photocatalysis Particle General Materials Science Surface plasmon resonance 0210 nano-technology Luminescence Plasmon |
| Zdroj: | Journal of Materials Chemistry A. 8:20581-20592 |
| ISSN: | 2050-7496 2050-7488 |
| DOI: | 10.1039/d0ta08001b |
| Popis: | Serendipitous observations offer newer insights into materials properties. Here we describe g-C3N4 nanosheets exhibiting remarkably blue-shifted photoluminescence within the 390–580 nm range centred at 425 nm which matches more closely with its ‘quantum-dots’, and yet is excitation-wavelength independent. Moreover, surprisingly, the luminescence decay becomes increasingly slow at higher emission wavelengths, by up to 10 times. The nanosheets absorb only a fraction of visible-light. To improve this, when we designed a nanocomposite of g-C3N4 and Au nanoparticles (NPs), it retained the PL characteristics and also exhibited excellent light-harvesting and photocatalytic efficiency for benzylamine (BA) oxidation. The surface plasmon resonance of the Au NPs is responsible for the high visible-light response and assisting the reaction by the ‘hot-electron’ injection mechanism, while an uncharacteristic, pronounced co-catalytic effect by them further improves the efficiency. The conversion is 98% with >99% selectivity over 1.5 h of natural sunlight and open-air, probably the highest efficiency for BA photo-oxidation reactions. Even though such a dual role by plasmonic NPs has remained unscrutinized, we argue that the charge-transfer processes for the ‘hot-carrier’ injection and co-catalytic events are well-separated in time due to a much slower photon incident frequency on a catalyst particle, enabling both to occur simultaneously in the same particle. |
| Databáze: | OpenAIRE |
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