Steering the Chemistry of Carbon Oxides on a NiCu Catalyst

Abstract

In the perspective of a sustainable energy economy, CO2\ud reduction is attracting increasing attention as a key step toward the synthesis of fuels and valuable chemicals. A possible strategy to develop novel conversion catalysts consists in mimicking reaction centers available in nature, such as those in enzymes in which Fe, Ni, and Cu play a major role as active metals. In this respect, NiCu shows peculiar activity for both water-gas shift and methanol\ud synthesis reactions. The identification of useful descriptors to engineer and tune the reactivity of a surface in the desired way is one of the main objectives of the science of catalysis, with evident applicative interest, as in this case. To this purpose, a crucial issue is the determination of the relevant active sites and rate-limiting steps. We show here that this approach can be exploited to design and tailor the catalytic activity and selectivity of a NiCu surface

In Situ Observation of Cu–Ni Alloy Nanoparticle Formation by X‐Ray Diffraction, X‐Ray Absorption Spectroscopy, and Transmission Electron Microscopy: Influence of Cu/Ni Ratio

“…These catalysts have been prepared by using different preparation methods such as: impregnation, [18,25] coprecipitation, [28] microemulsion, [29] and sol-gel methods, [30] and have been supported on different high surface area materials such as SiO 2 , [18,25,31,32] Al 2 O 3 , [28,33,34] ZnO, [17] TiO 2 , [11,12,35] ZrO 2 , [36,37] CeO 2 , [38] zeolite, [33] and carbon nanotubes. [39] Moreover, the selectivity and/or the activity is reported to change significantly upon variation in the Cu/Ni ratio for reactions such as hydrocarbon hydrogenolysis, [14] steam reforming, [25] CO 2 hydrogenation, [40,41] CO hydrogenation, [17] and water-gas shift. [42] These changes in selectivity and/or activity are largely related to the structure of the catalysts.…”

An in situ near-ambient pressure X-ray Photoelectron Spectroscopy study of Mn polarised anodically in a cell with solid oxide electrolyte

“…In the presence of CO 2 , both without and with H 2 O, the C 1s spectra (Fig. 5-A) measured at OCP show the presence of a C deposit, as shown by the welldefined peak at 284.5 eV [41]. The presence of carbon deposits at high temperature (600 C) at the surface of the Mn pristine electrode under OCP conditions can be ascribed to accumulation of unreacted carbon stemming from dissociation of gas-phase molecules and, more likely, to carbon segregation from the bulk of the metallic electrode.…”

“…641 eV and the presence of the shake-up shoulder at ca. 647 eV lead to the unambiguous identification of the presence of MnO at the electrode [40,41,43,46,47].…”

Microwave, Ultrasound, and Mechanochemistry: Unconventional Tools that Are Used to Obtain “Smart” Catalysts for CO2 Hydrogenation

“…The chemical processes for CO 2 reutilization are catalytic [13][14][15], photocatalytic [16][17][18][19][20], electrocatalytic [21][22][23][24][25], or photoelectrocatalytic [18,26]. As a whole, the chemical reduction of CO 2 is a challenge from both the industrial and the catalytic point of view [27], but it is also a hot scientific topic, since CO 2 is an ideal C1 feedstock for producing different types of chemicals and, ultimately, fuels.…”