Laser radiation, CDs and Pd-NPs: Three influential factors to enhance the hydrogen storage capacity of porous silicon

Abstract

In This study, n-type single-crystal silicon was used to make porous silicon by electrochemical and photoelectrochemical methods to investigate the hydrogen storage capacity. Carbon dots are made via a hydrothermal method, and palladium nanoparticles are decorated on porous silicon by electroless and drip processes. The morphology of the structures has been investigated using field emission scanning electron microscope, atomic force microscope and X-ray diffraction. The samples' electrochemical characteristics and hydrogen storage capacity have been studied by cyclic voltammetry and chronopotentiometry methods. The results show that laser irradiation for 0.5 h on the back of silicon wafers during the etching prosses increases the storage capacity in porous silicon by 45%. Adding carbon dots and palladium nanoparticles to porous silicon made by the photoelectrochemical method increases hydrogen storage capacity by 29% and 64%, respectively. The hydrogen storage capacity in porous silicon made by the photoelectrochemical method simultaneously decorated with palladium nanoparticles and carbon dots was 1.02% by weight, which shows an increase of 82% compared to undecorated porous silicon.