Xl30 esem

Thermogravimetric analysis (TGA) was used to determine the inorganic content of the samples. A TA Instrument STD600 thermobalance was used for this purpose. In a typical experiment, a ca. 5 mg sample was heated up in flowing air (100 mL min -1 ) at a heating rate of 5°C min -1 to 700°C where the sample was held isothermal for 60 min.
The residual weight was due to inorganic oxides, Ga2O3 or Fe2O3. Details of calculation can be found in Supplementary Information. The surface morphology and the metal distribution of samples were studied by a scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy. Energy-dispersive X-ray (EDX) spectroscopy was performed in conjunction with scanning electron microscopy (SEM) on a Philips XL30 ESEM with an attached Oxford Instruments x-act EDX detector. EDX spectroscopy was used to determine the elemental composition of the materials, whilst the micrographs taken provide a visual representation of the morphology of the products. About 0.5 mg of each material was placed on carbon tape; the materials were insufficiently conductive and gold sputtering was required to enhance the conductivity prior to imaging. All micrographs and EDX spectra were recorded using a beam current of 20 kV. A Thermo Scientific Nicolet iS5 spectrometer was used for FTIR spectroscopy with 16 scans for each sample at a resolution of 4 cm -1 .