DFT simulations of dissociative chemisorption of sulfur-, nitrogen- and oxygen-containing molecules on mixed oxides with Mg, Al and Zn

Site-Specific Hydrogen Reactivity of Zn0.05Mg0.95O Nanopowders

“…Therefore, we can retain as a guideline that the very local effect of segregated Zn is likely limited to its first oxygen neighbors. 19,27 Shoulder at 3745 cm −1 (Zn 3C /O 3C versus Mg IC /O 3C ). The low-intensity signal at 3745 cm −1 , which is observed only in the spectrum of Zn 0.05 Mg 0.95 O, might be an effect of the nonuniform local density of segregated Zn.…”

“…17,26 However, little is known to which extent doping atoms perturb the matrix of the host oxide. In particular, a crucial issue is to know whether the doping modifies the sites only locally 19,27 or if, conversely, it induces a charge redistribution which affects a wider neighborhood. Adsorbed protons are of great relevance to probe MgO and ZnO surfaces.…”

“…In this context, the most studied system is ZnO–MgO, which mixes a semiconductor and an insulator and whose band gap goes from 3.37 to 7.8. At the two ends of the phase diagram, Mg-doped ZnO and Zn-doped MgO keep the ZnO wurtzite and MgO cubic structure, respectively, while the medium composition range consist in a mixture of the two phases. − In addition to the optical and semiconductor properties, which are based in particular on the variable band gap, − Zn x Mg 1– x O combines the rich surface chemistry of the two parent oxides and has multiple catalytic, − photocatalytic, , antibacterial, − and antifungal applications . Changes in surface chemistry clearly correlate with dopant-induced electronic states that show up in valence bands of mixed oxides. , However, little is known to which extent doping atoms perturb the matrix of the host oxide.…”

“…Changes in surface chemistry clearly correlate with dopant-induced electronic states that show up in valence bands of mixed oxides. , However, little is known to which extent doping atoms perturb the matrix of the host oxide. In particular, a crucial issue is to know whether the doping modifies the sites only locally , or if, conversely, it induces a charge redistribution which affects a wider neighborhood.…”

Ciência dos Materiais: Pesquisas e desenvolvimento no âmbito da UFAM

“…Neste modelo da Figura 1b, c, d é possível observar um espaço de vaca ncia da camada que está fracamente conectadas entre si por ligações de van der Walls possibilitando (YAMAGUCHI et al, 2019). O que faz com que as suas moléculas tenham a tendência de se orientar em folhas paralelas empilhadas, para aumentar ao máximo a força atrativa entre elas pela aproximação de seus átomos (FONSECA et al, 2019). Esta orientação aproximadamente paralela nos planos (001) dos cristais confere uma estrutura laminada à bentonita o que faz com que o seu reticulado cristalino apresente uma fácil clivagem basal (GRIM; KULBICKI, 1961;KRUTPIJIT et al, 2019).…”