Thermodynamic Modeling of Uranium (VI) Reductive Immobilization in Groundwater of NPCC Sludge Storages (Novosibirsk, Russia)

Ras, Mineralogy Sb; Novosibirsk,; Moscow,

doi:10.4236/gep.2018.611014

Cited by 1 publication

(2 citation statements)

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“…For Pd-based EAH catalysts with high stability, selectivity, and FE, three factors should be considered: (1) the relatively high potential of catalyst oxidation to avoid catalyst dissolution, (2) easy desorption of alkene and difficult formation of PdH x to avoid overhydrogenation, and (3) higher energy barriers for H* self-coupling than H* added to alkyne molecules to suppress competitive HER. We first compare the theoretical potentials of N, S, and P oxidation with alkyne reduction in a pH 14 electrolyte (Figure a). − The oxidation potentials of N, S, and P follow the trend of P (−2.6 V vs Hg/HgO) > S (−1.2 V vs Hg/HgO) > N (−0.8 V vs Hg/HgO). Additionally, the vacancy formation energies of Pd 2 N, Pd 2 S, and Pd 2 P anions are calculated to be 1.88, 1.55, and 1.49 eV, respectively (see Figure S1 in the Supporting Information).…”

Section: Results and Discussionmentioning

confidence: 99%

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Interstitial Modification of Palladium Nanocubes with Nitrogen Atoms Promotes Aqueous Electrocatalytic Alkyne Semihydrogenation

Song,

Cheng,

Wang

et al. 2023

ACS Materials Lett.

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Developing nanostructures to drive the selective and durable electrocatalytic semihydrogenation of alkynes to alkenes with a high Faradaic efficiency (FE) is highly desirable. Here, we propose that the desired catalytic materials should meet three requirements: (1) catalyst oxidation potential higher than alkyne reduction potential, (2) easy desorption of alkene and difficult formation of PdH x , and (3) higher energy barriers for H* self-coupling than H* adds to an alkyne molecule. Thus, Pd 2 N nanocubes with nitrogen-atom-modified Pd interstitial sites are designed and synthesized to achieve 95.7% alkyne conversion, 97.8% alkene selectivity, and 72.4% alkene FE. The catalyst can be used for 18cycle measurements without performance decline. A mechanistic study shows that the high selectivity is due to the inhibited PdH x , the weakened alkene adsorption, and the increased energy barrier for alkene hydrogenation. The high energy barrier for H* coupling to release H 2 leads to the high alkene FE. In addition, the potential-independent alkene selectivity enables Pd 2 N to fit the fluctuating voltage in a solar-powered system. Furthermore, Pd 2 N is suitable for other functionalized alkynes and deuterated alkyne semihydrogenation.

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Section: Results and Discussionmentioning

confidence: 99%

“…(a) Oxidation potential of S, P, and N in pH 14 electrolyte. − (b) Styrene adsorption energy on Pd and Pd 2 N surfaces. (c) Proposed PdH x inhibition mechanism for Pd–N.…”

Section: Results and Discussionmentioning

confidence: 99%