for refining the Raman shifts (cm -1 ). Raman bands are often influenced by strain, particle distribution, vibration bands of amorphous silica and presence of surface species. For the presented data, the wavelength of 638 nm was selected for sharp visualization of peaks and lower signal-to-noise ratio at higher wavenumber (cm -1 ). The morphologies of the catalysts were characterized by using scanning electron microscopy (SEM) JEOL JSM-7401F, with an acceleration voltage of 5 kV. The metallic concentration was verified by using ICP-OES equipment (NexION™ 350D-Optima 8300, PerkinElmer). Whereby, 1 mg of each catalyst sample was digested in a 5 % HNO3 solution prior to analysis. The measurement was performed at room temperature and in triplicates.