Aluminum compounds 2 Mg-Al layered double hydroxide % reductions 1 4-Nitrophenol 1 AuNPs/graphene 1 Binding sites 1 Charge transfer 1 Chemical bonds 1 Computation theory 1 Coprecipitation method 1 Density functional theory 1 Density functional theory studies 1 Dodecyl sulphate 1 Energy gap 1 Fiber optic sensors 1 Fourier transform infrared spectroscopy 1 Gold Nanoparticles 1 Gold nanoparticle 1 Gold nanoparticles 1 Graphene 1 Graphene nanoplatelets 1 Heavy metals 1 High resolution transmission electron microscopy 1 Hydrotalcite 1 Hydrotalcites 1 Layered-double hydroxides 1 Lead compounds 1 Magnesium compounds 1 Metal complexes 1 Metal ions 1