Ftir 600

Confocal fluorescence microscopy studies were performed with a Nikon Eclipse LV150 upright microscope with a 50×0.55 NA dry objective lens. The confocal fluorescence images were collected with the use of a Nikon-Eclipse C1 head connected to the laser light sources (405, 488 and 561 nm). The emission was detected with three photomultiplier tubes in the range 425–475, 510–550 and 575–635 nm for the three lasers, respectively (in order to avoid channel overlap). Large zeolite ZSM-5 crystals were loaded into an in situ cell (Linkam FTIR 600) equipped with a temperature controller (Linkam TMS 93). The crystals were placed in a flow of 50 mL min⁻¹ O₂ and heated to 500 °C at a rate of 15 °C min⁻¹, the crystals were kept at this temperature for 1 h before being cooled to required reaction temperature (at a rate of 15 °C min⁻¹). Once the reaction temperature was achieved, the flow was changed to 50 mL min⁻¹ N₂ only. Subsequently, the N₂ flow was diverted through a bubbler containing methanol or ethanol for the desired reaction time. The fluorescence intensity was measured across both the middle and surface (top) planes of the zeolite H-ZSM-5 crystals (Figure 2) at varying times under reaction conditions.

The UV/Vis micro-spectroscopy measurements were performed with an Olympus BX41 upright microscope using a 50×0.5 NA high working-distance microscope objective lens. A 75 W tungsten lamp was used for illumination. In addition, the microscope has a 50/50 double viewpoint tube, which accommodates a CCD video camera (ColorView IIIu, Soft Imaging System GmbH) and an optical fibre mount. A 200 μm core fibre connects the microscope to a CCD UV/Vis spectrometer (AvaSpec-2048TEC, Avantes BV). The large zeolite H-ZSM-5 crystals were loaded into an in situ cell (Linkam FTIR 600) equipped with a temperature controller (Linkam TMS 93). The crystals were placed in a flow of 10 mL min⁻¹ O₂/40 mL min⁻¹ N₂ and heated to 500 °C at a rate of 15 min⁻¹, the crystals were kept at this temperature for 1 h before cooling to required reaction temperature (at a rate of 15 min⁻¹). Once the reaction temperature was achieved, the flow was changed to 50 mL min⁻¹ N₂ only. Subsequently, the N₂ flow was diverted through a bubbler containing methanol or ethanol for the desired reaction time.