To develop promising adsorbent candidates for adsorptive denitrogenation, we screened the adsorption of NO, NO2, and NH3 in 19 M-HKUST-1 (M = Be, Fe, Ni, Cr, Co, Cu, V, Zn, Mo, Mn, W, Sn, Ti, Cd, Mg, Sc, Ca, Sr, and Ba) systematically using first-principle calculations. Of these, four variants of M-HKUST-1 (M = Ni, Co, V, and Sc) yield more negative adsorption Gibbs free energy ΔGads than the original Cu-HKUST-1 for three adsorbates, suggesting stronger adsorbate binding. Ti-HKUST-1, Sc-HKUST-1, and Be-HKUST-1 are predicted to have the largest NO, NO2, and NH3 adsorption energies within the screened M-HKUST-1 series, respectively. With the one exception of NO2 dissociation on V-HKUST-1, dissociative adsorption of NO, NO2, and NH3 molecules on the other considered M-HKUST-1 is energetically less favorable than molecular adsorption thermodynamically. The barrier calculations show that the dissociation is difficult to occur on Cu-HKUST-1 kinetically due to the very large dissociation barrier. Electronic analysis is provided to explain the bond nature between the adsorbates and M-HKUST-1. Note that the isostructural substitution of Cu to the other metals is a major simplification of the system, representing the ideal situation; however, the present study provides interesting targets for experimental synthesis and testing.

Functionalization of metal−organic frameworks (MOFs) ligands can tune the adsorption properties of the MOFs. The adsorptions of NO, NO2, NH3, C5H5N, C4H5N, and C4H4O on the pristine and five X-functionalized...

The interfacial stability of copper/diamond directly affects its mechanical properties and thermal conductivity. The atomic structures and electronic properties of Cu/diamond and Cu/X/diamond interfaces have been identified to investigate the effect of interfacial additive X (X = Ni or N) on the low-index interfacial adhesion of copper/diamond composites. For unmodified composites, the interfacial stability decreases in the order of Cu(0 0 1)/diamond(0 0 1) > Cu(1 1 1)/ diamond(1 1 1) > Cu(0 1 1)/diamond(0 1 1). The metallic interfacial additive Ni is found to enhance the Cu(0 1 1)/diamond(0 1 1) interfacial stability and exchange the interfacial stability sequence of (0 1 1) and (1 1 1) composites. The nonmetallic element N will promote the stability of Cu(1 1 1)/diamond(1 1 1) but not alter the stability order of the composites at different interfaces. To explain the origin of interfacial stability, a series of analyses on atomic structures and electronic properties have been carried out, including the identification of the type of formed interfacial boundaries, the measurement of interfacial bond lengths, and the calculations of density of states, bond populations, and atomic charge. The stability of the interface is found to be related to the type of formed interfacial boundary and bond, the interfacial bond populations, and the interfacial bond numbers. The layer-projected density of states reveals that all of the considered interfaces exhibit metal characteristics. The interfacial Ni additive is found to be an electron donor contributing the electrons to its bonded Cu and C atoms while the interfacial N atom is an electron acceptor where it mainly accepts the electrons from its bonded Cu and C.

Comprehending the bond nature of ethylene-metal clusters at the atomic level is important for the design of nanocatalysts and their applications in the fields of fine chemistry and petroleum refining. The growth of Irn (n = 1–10) on γ–Al2O3(110) and ethylene adsorption on bare and γ–Al2O3(110)-supported Irn (n = 1–10) clusters were investigated using the density functional theory (DFT) approach. The mode stability of ethylene adsorption on the bare Irn clusters followed the order π > di-σ > B-T, with the exception of Ir8 where the π structure was less stable than the di-σ configuration. On supported Irn (n = 4–7 and 10) the stability sequence was π > di-σ > di-σ′ (at interface), while on supported Irn (n = 2, 3, 8, and 9) the sequence changed to di-σ > π > di-σ′ (at interface). Two-thirds of ethylene adsorption on the supported Irn clusters were weaker than its adsorption on the bare Irn clusters. The pre-adsorbed ethylene at the interface was found to facilitate the nucleation from the even-sized supported Irn to odd-sized Irn clusters, but hindered the nucleation from the odd-sized Irn to even-sized Irn clusters.