Biodiesel is one of the renewable energy (RE) sources that has received much interest due to its promising properties. Recently, the use of coconut oil as biodiesel has caught the attention of many researchers. As a result, this paper presents a comprehensive overview of the current catalysts used to produce coconut oil biodiesel via the transesterifcation method.

Carboxymethyl cellulose (CMC) is a derivative of cellulose that shares its biodegradability, biocompatibility,and renewability while being soluble in water and some organic solvents. It is due to these characteristics that the aerogel produced from CMC will share these advantages. In this study,we produced CMC carbon aerogel from different concentrationsof CMC aerogels (1%, 2%, 3%, 4%) and under different carbonisation temperatures (300 °C, 400 °C, 500 °C, 600 °C, 700 °C and 800 °C) for a period of 1 hour and 2 hours. The prepared CMC carbon aerogel samples were then analysed based on the difference in mass loss,which differed according to the varying experimental parameters. In temperatures varying from 300 °C to 600 °C,there was a decrease in mass loss as the concentration was increased due to the physical properties of the CMC aerogel. At higher temperatures of 700 °C and 800 °C,the mass loss at higher concentrations of CMC increased due to the completed decomposition and carbonisation of CMC aerogel.

A direct, simple and low-cost approach to synthesising carbon aerogelmagnesium (CA-Mg) composites has been demonstrated in this research. It is conducted by carbonising sodium carboxymethyl cellulose (CMC) aerogels via a sol-gel and freezedrying process. Mg is used as an enhancer for CA in the preparation step and as a selective candidate for the hydrogen storage device. Note that the structure and morphology of CA-Mg composites are characterised using field emission scanning electron microscopy (FESEM), fourier transforms infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. The ability of CA-Mg composites to act as a hydrogen storage device is analysed by utilising Brunauer-Emmett-Teller (BET) and temperature-programmed desorption analysis. The CA-Mg composites comprise porous structures with a high specific surface area of 101.4407 m2 /g, and 0.002 mol of Mg2+ is the optimum concentration for synthesising CA-Mg composites. As a potential candidate for a hydrogen storage device, the CA-Mg composites show an initial dehydrogenation temperature of 377.22°C, where they desorbed the maximum amount of hydrogen gas. This study emphasises the potential for using CA as a hydrogen storage device, which fulfils the seventh goal of the Sustainable Development Goals (SDGs), affordable and clean energy, as well as Department of Energy (DOE)’s goal of using carbon-based materials.