Role of functionalized graphene quantum dots in hydrogen evolution reaction: A density functional theory study. (25th December 2022)

• Record Type: Journal Article
• Authors: Sharma, Vaishali; Roondhe, Basant; Saxena, Sumit; Shukla, Alok
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 99(2022)
• Page Start: 41748
• Page End: 41758
• Publication Date: 2022-12-25
• Subjects: Hydrogen evolution reaction -- Graphene quantum dots -- Functionalization -- Density functional theory -- Overpotential; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.02.161
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Rapid advances in the field of catalysis require a microscopic understanding of the catalytic mechanisms. However, in recent times, experimental insights in this field have fallen short of expectations. Furthermore, experimental searches of novel catalytic materials are expensive and time-consuming, with no guarantees of success. As a result, density functional theory (DFT) can be quite advantageous in advancing this field because of the microscopic insights it provides and thus can guide experimental searches of novel catalysts. Several recent works have demonstrated that low-dimensional materials can be very efficient catalysts. Graphene quantum dots (GQDs) have gained much attention in past years due to their unique properties like low toxicity, chemical inertness, biocompatibility, crystallinity, etc. These properties of GQDs which are due to quantum confinement and edge effects facilitate their applications in various fields like sensing, photoelectronics, catalysis, and many more. Furthermore, the properties of GQDs can be enhanced by doping and functionalization. In order to understand the effects of functionalization by oxygen and boron based groups on the catalytic properties relevant to the hydrogen-evolution reaction (HER), we perform a systematic study of GQDs functionalized with the oxygen (O), borinic acid (BC2 O), and boronic acid (BCO2 ). All calculations that included geometry optimization, electronic and adsorption mechanism, were carried out using the Gaussian16 package, employing the hybrid functional B3LYP, and the basis set 6-31G(d, p). With the variation in functionalization groups in GQDs, we observe significant changes in their electronic properties. The adsorption energy Eads of hydrogen over O-GQD, BC2 O-GQD, and BCO2 -GQD is −0.059 eV, −0.031 eV and −0.032 eV respectively. Accordingly, Gibbs free energy (ΔG) of hydrogen adsorption is extraordinarily near the ideal value (0 eV) for all the three types of functionalized GQDs. Thus, the present work suggests pathways for experimental realization of low-cost and multifunctional GQDs based catalysts for clean and renewable hydrogen energy production. Graphical abstract: Image 1 Highlights: Hydrogen adsorption on functionalized GQDs was investigated using DFT. Effect of oxygen (O), borinic acid (BC2 O), and boronic acid (BCO2 ) was studied. H2 -O-GQD presents highest value of ϕ (4.120 eV) suggesting its higher stability. The highest E a d s of −0.059 eV is obtained for H2 -O-GQD. The ΔG of H2 -O-GQD is more favourable as compared to H2 -BC2 O-GQD and H2 -BCO2 -GQD.