Hydrogen adsorption on pristine and platinum decorated graphene quantum dot: A first principle study. (7th September 2020)

• Record Type: Journal Article
• Authors: Sharma, Vaishali; Kagdada, Hardik L.; Wang, Jinlan; Jha, Prafulla K.
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 44(2020)
• Page Start: 23977
• Page End: 23987
• Publication Date: 2020-09-07
• Subjects: Graphene quantum dots -- Adsorption mechanism -- Hydrogen evolution reaction -- Site dependence -- Hydrogen storage; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.09.021
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In the ever growing demand of future energy resources, hydrogen production reaction has attracted much attention among the scientific community. In this work, we have investigated the hydrogen evolution reaction (HER) activity on an open-shell polyaromatic hydrocarbon (PAH), graphene quantum dot "triangulene" using first principles based density functional theory (DFT) by means of adsorption mechanism and electronic density of states calculations. The free energy calculated from the adsorption energy for graphene quantum dot (GQD) later guides us to foresee the best suitable catalyst among quantum dots. Triangulene provides better HER with hydrogen placed at top site with the adsorption energy as −0.264 eV. Further, we have studied platinum decorated triangulene for hydrogen storage. Three different sites on triangulene were considered for platinum atom adsorption namely top site of carbon (C) atom, hollow site of the hexagon carbon ring near triangulene's unpaired electron and bridge site over C–C bond. It is found that the platinum atom is more stable on the hollow site than top and bridge site. We have calculated the density of states (DOS), highest occupied molecular orbitals (HOMO), lowest unoccupied molecular orbitals (LUMO) and HOMO-LUMO gap of hydrogen molecule adsorbed platinum decorated triangulene. Our results show that the hydrogen molecule (H2 ) dissociates instinctively on all three considered sites of platinum decorated triangulene resulting in D-mode. The fundamental understanding of adsorption mechanism along with analyses of electronic properties will be important for further spillover mechanism and synthesis of high-performance GQD for H2 storage applications. Graphical abstract: Image 1 Highlights: HER activity of graphene quantum dot "triangulene" is studied. Triangulene provides better HER with hydrogen adsorption energy of −0.264 eV. Site dependent influence of Pt over GQD is evaluated for hydrogen storage. Hydrogen on Pt decorated GQD with bridge, hollow and top sites results in D-mode.