Local hot charge density regulation: Vibration-free pyroelectric nanogenerator for effectively enhancing catalysis and in-situ surface enhanced Raman scattering monitoring

Highly efficient catalysis and monitoring play an extremely important role in the modern chemical industry. The local thermal charge density, which is proportional to the square of the local near-field enhancement, is essential to improve the catalytic efficiency. However, the vibration-free way to improve the local hot charge density at the surfaces of the catalyst still needs to be investigated. Optical energy is one of the most promising green energy sources in the natural environment. Here, we designed a pyroelectric nanogenerator by absorbing optical energy as surface enhanced Raman scattering (SERS) substrate for in-situ monitoring the complete oxidation reaction from 4-aminothiophenol (4-ATP) to 4-nitrothiophenol (4-NTP) and the oxygen reduction reaction (ORR) intermediates. The pyroelectricity could be easily generated by the simulated sunlight illumination and was investigated in theory and experiment. The electric field induced by the coupling of pyroelectric and plasmonic effect can effectively tune the hot charge density on the surface of SERS substrate, which further increases the SERS signals and efficiently drives the catalytic process. The proposed measuring strategies of catalytic and SERS enhancement can promote energy conservation and environmental protection.