OperandoUV-vis spectroscopy for real-time monitoring of nanoparticle size in reaction conditions: a case study on rWGS over Au nanoparticlesElectronic supplementary information (ESI) available. See DOI: https://doi.org/10.1039/d3cy01392h

We propose the use of surface plasmon resonance (SPR) as a distinctive marker for real-time monitoring in reaction conditions of gold nanoparticles supported on α-Al2O3. The study leverages the SPR shape-and-size dependency to monitor metal nanoparticles in reaction conditions, evidencing an influence of both dimensions and agglomerations on the SPR peak position. Operandomeasurements, coupling UV-vis spectroscopy and catalytic testing, allows to follow the dynamics during nanoparticle formation (Au3+to Au0reduction) and during the reverse water gas shift reaction (CO2+ H2→ CO + H2O). The catalyst structure and stability in reaction conditions was further confirmed by operandoX-ray spectroscopy and PXRD data. Overall, this approach enables the direct acquisition of information on the structure–activity relationship of metal-based supported catalysts under actual reaction conditions.