Catalyst Structure-Performance Relationship Identified by High-Throughput Operando Method: New Insight for Silica-Supported Vanadium Oxide for Methanol Oxidation

The reaction mechanism of methanol oxidation catalyzed by vanadium oxides on a silica support (V₂O₅/SiO₂) was investigated in a high-throughput operando reactor coupled with a Fourier transform-infrared (FT-IR) imaging system for rapid product analysis and six parallel, in situ Raman spectroscopy probes for catalyst characterization. Up to six V₂O₅/SiO₂ catalysts with different vanadium loadings (i.e., from 0 to 7%) were simultaneously monitored under identical experimental conditions. The specific Raman bands of the different catalysts in the six parallel reaction channels are quantitatively determined in this work. Under steady-state reaction conditions, the Raman intensities of C–H stretch in Si–O–CH₃ and V–O–CH₃ were extensively studied at different reaction temperatures and different vanadium loadings. For the first time, we observed enhanced Si–O–CH₃ formation on V₂O₅/SiO₂ catalysts with low vanadium loadings. We attribute this phenomenon to surface cluster edge activation. Careful comparison of the in situ Raman intensity of V–O–CH₃ on V₂O₅/SiO₂ catalysts revealed different methoxy formation mechanisms in different reaction temperature regimes.