Supercritical microalgae conversion to biofuel and value-added components (oxygenates, hydrocarbons, and aromatics): A catalyst characterization study

The study aimed to investigate the use of SrO/TiO₂ nano-catalysts in the one-pot production of valuable products (such as fatty acid methyl esters, oxygenates, hydrocarbons, and aromatics) from Chlorella vulgaris microalgae through a supercritical process. The research focused on examining the impact of the factors, the SrO to TiO₂ ratio, preparation method, and calcination temperature on the catalytic performance. Two calcination temperatures (600°C and 850°C), two Sr:Ti molar ratios (1 and 2), and two catalyst preparation methods (photochemical and impregnation) were considered. The catalysts were characterized using Scanning electron microscopy, transmission electron microscope, x-ray crystallography, and Brunauer-Emmett-Teller techniques. The evaluation of catalyst performance primarily focused on the production of value-added products, particularly fatty acid methyl esters (FAMEs). The results indicated that the catalyst prepared using the photochemical method with a Sr:Ti molar ratio of 2 and calcined at 850°C exhibited superior performance in terms of FAMEs and oxygenates production. It was demonstrated that the catalyst prepared using the photochemical method with higher Sr:Ti ratio had better performances in the production of biodiesel.