The FESEM images were acquired using TESCAN MIRA3 FEG-SEM instrument equipped with an Oxford Instruments Aztec Energy X-maxN 80 EDX system. The UV-vis spectra were recorded using a Varian Cary 50 UV-vis spectrophotometer. The ICP-OES measurements were performed on a Thermo Scientific iCAP 7400 ICP-OES DUO spectrometer at the Microanalysis Service, Yusuf Hamied Department of Chemistry, University of Cambridge.