Stability, Energetic, and Reactivity Properties of NiPd Alloy Clusters Deposited on Graphene with Defects: A Density Functional Theory Study

Abstract

Graphene with defects is a vital support material since it improves the catalytic activity and stability of nanoparticles. Here, a density functional theory study was conducted to investigate the stability, energy, and reactivity properties of NinPdn (n = 1–3) clusters supported on graphene with different defects (i.e., graphene with monovacancy and pyridinic N-doped graphene with one, two, and three N atoms). On the interaction between the clusters and graphene with defects, the charge was transferred from the clusters to the modified graphene, and it was observed that the binding energy between them was substantially higher than that previously reported for Pd-based clusters supported on pristine graphene. The vertical ionization potential calculated for the clusters supported on modified graphene decreased compared with that calculated for free clusters. In contrast, vertical electron affinity values for the clusters supported on graphene with defects increased compared with those calculated for free clusters. In addition, the chemical hardness calculated for the clusters supported on modified graphene was decreased compared with free clusters, suggesting that the former may exhibit higher reactivity than the latter. Therefore, it could be inferred that graphene with defects is a good support material because it enhances the stability and reactivity of the Pd-based alloy clusters supported on PNG.

Theoretical study of PdNi and PdCu clusters embedded on graphene modified by monovacancy and nitrogen doping

“…[18][19][20][21][22][23][24] The stability and reactivity of nanoparticles formed by Pd and 3d transition metals deposited on modified graphene have been investigated in some theoretical studies. [25][26][27][28][29] For instance, the stability and reactivity of icosahedral M@Pd 12 (M = Fe, Co, Ni, Cu, Zn, Pd) core-shell nanoclusters deposited on single vacancy graphene (SVG) were investigated employing density functional theory (DFT). 25 The interaction energies between the M@Pd 12 nanoclusters and the SVG were larger than À5 eV, evidencing a remarkable stability of the M@Pd 12 nanoclusters supported on SVG.…”

“…In another study, the stability and reactivity of Ni n Pd n (n = 1-3) clusters deposited on SVG and PNG were investigated employing ADFT calculations. 28 It was observed that the Ni n Pd n clusters were more strongly adsorbed on SVG than on PNG. Also, the chemical hardness computed for the Ni n Pd n clusters deposited on modified graphene decreased with respect to the values reported to bare clusters, indicating that the Ni n Pd n /SVG and Ni n Pd n /PNG composites may exhibit greater reactivity than the one of bare Ni n Pd n clusters.…”

“…These studies provide good evidence on the stability and reactivity of Pd systems alloyed with 3d transition metals. [25][26][27][28][29] However, to the best of our knowledge, there exist so far are no theoretical investigations on the stability and reactivity of compounds formed by Pd and different 3d transition metals deposited on graphene with different defects. Therefore, this study is focused to explore the stability and reactivity properties of Pd 4 Ni 4 and Pd 4 Cu 4 clusters deposited on SVG and PNG based on ADFT calculations.…”

“…The stability and reactivity of nanoparticles formed by Pd and 3 d transition metals deposited on modified graphene have been investigated in some theoretical studies 25–29 . For instance, the stability and reactivity of icosahedral M@Pd 12 (M = Fe, Co, Ni, Cu, Zn, Pd) core‐shell nanoclusters deposited on single vacancy graphene (SVG) were investigated employing density functional theory (DFT) 25 .…”

Density Functional Theory-Based Approaches to Improving Hydrogen Storage in Graphene-Based Materials

“…Another route used to modify the properties of pristine graphene is through substitutional point defects such as doping. This approach substantially modifies the reactivity of pristine graphene [ 95 , 96 , 97 , 98 , 99 , 100 ]. At the DFT level, different types of doping have been investigated to modify the reactivity of graphene [ 61 , 62 , 79 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 ].…”