Adsorption of Transition-Metal Clusters on Graphene and N-Doped Graphene: A DFT Study

Abstract

Using the dispersion-corrected density functional theory (DFT-D3) method, we systematically studied the adsorption of 15 kinds of transition-metal (TM) clusters on pristine graphene (Gr) and N-doped graphene (N-Gr). It has been found that TM n (n = 1–4) clusters adsorbed on the N-Gr surface are much stronger than those on the pristine Gr surface, while 3d series clusters present similar geometries on Gr and N-Gr surfaces. The most preferred sites of TMs migrate from hollow to bridge to the top site on the Gr surface along the d series in the periodic table, while the preferred sites of TMs migrate in a much more complex manner on the N-Gr surface. It has also been found that charge transfer decreases along the d series for adsorbed clusters on both surfaces, but adsorbed clusters present less charge transfer on the N-Gr surface than on the Gr surface. What is more interesting is that some TM (Tc, Ru, and Re) clusters change the growth mechanism from the three-dimensional (3D) growth mode on the Gr surface to the two-dimensional (2D) growth mode on the N-Gr surface. At last, it has been found that adsorbed clusters are more dispersed on the N-Gr surface than on the pristine Gr surface due to growth and average aggregation energies.

Investigation of the Stability and Hydrogen Evolution Activity of Dual-Atom Catalysts on Nitrogen-Doped Graphene

“…Comparing Table 1 and Table 2 , for elements (Cr, Mo, Pd, Ag, W, Ir, and Pt) whose B site is the best adsorption site on pure graphene, the value difference between and of Pd(Pt) is relatively small, making the C-C bonds (B site) and the single-defect vacancy (S site) to single atom in Pd− SVGN 3 (Pt− SVGN 3 ) competitive for the adsorption of a single atom, eventually resulting in one d M1−Nx that is much larger than the other two. All the results are consistent with previous works [ 40 , 42 , 43 , 44 ]. As shown in Figure 2 , we found much stronger than , which is in line with the expectation.…”

Enhanced stability of sub-nanometric iridium decorated graphitic carbon nitride for H2 production upon hydrous hydrazine decomposition

“…In the 3pN model the support to cluster charge transfer is 𝑛 𝑞 -𝑞 -𝑐𝑙𝑢𝑠 enhanced with respect to gN (Table 4). Such charge transfer is due to the pyridinic N sites, leading to strongly localized positive charges at the cluster-support interface ( = 2, = 0.79 |e -|), in agreement with 𝑛 𝑞 + 𝑞 + 𝑐𝑙𝑢𝑠 recent computational studies, 116,117 along with the highest number of negative charges distributed on the cluster surface ( = 13, = -0.31 |e -|), as shown in Figure 10. Noticeably, both the GCN models 𝑛 𝑞 -𝑞 -𝑐𝑙𝑢𝑠 exhibited a higher value of redistributed negative charges ( = -0.29 and -0.31 |e -|, respectively for gN 𝑞 -𝑐𝑙𝑢𝑠 and 3pN) compared to the graphite models ( = -0.19 and -0.25 |e -|, respectively for PG and SV).…”

Drone Delivery of Dehydro-Sulfurization Utilizing Doubly-Charged Negative Ions of Nanoscale Catalysts Inspired by the Biomimicry of Bee Species’ Bio-Catalysis of Pollen Conversion to Organic Honey

“…Oxidation-reduction speed is therefore predicted to be regulated by the size, type, and charge of any given sample of catalysts used to produce the elemental Sulfur and water products for both steps of the reaction. Hence, the quality, quantity, and overall efficiencies of the reactions can be tailored to the reactivity of each step of the ORR reaction as well as the type of nanoscale catalyst that is used [32][33][34][35]. Transition state theory is executed by performing Density Functional Theory approximations shown to be excellent for predicting chemical, physical, and electromagnetic properties of nanoscopic systems.…”