Catalyst activity 42 Biodiesel 9 Catalytic performance 6 Reusability 6 Transesterification 6 Biodiesel production 5 Carbon 5 Fatty acids 5 Molar ratio 5 Nanocatalysts 5 Nickel compounds 5 Palm oil 5 Scanning electron microscopy 5 Binary alloys 4 Biomass 4 Degradation 4 Electrocatalysts 4 Enzyme activity 4 Esters 4 Heterogeneous catalyst 4 Nanostructured materials 4 Synthetic fuels 4 Temperature 4 Temperature programmed desorption 4 Thermogravimetric analysis 4 X ray diffraction 4 ]+ catalyst 4 catalyst 4 Carbon dioxide 3 Chlorine compounds 3