We report the preparation and electrocatalytic performance of silver-containing gas diffusion electrodes (GDE) derived from a silver coordination polymer (Ag-CP). Layer-bylayer growth of the Ag-CP onto porous supports was applied to control Ag loading. Subsequent electro-decomposition of the Ag-CP resulted in highly selective (FECO > 90%) and stable CO2to-CO gas diffusion electrodes in aqueous CO2 electroreduction over a wide potential range, with jCO ≈ 30.2 mA cm −2 at −1 V vs RHE. To further explore the potential of this electrode preparation method, the MOF-mediated approach was transferred to a gas-fed flow electrolyzer for high-current density tests. The in-situ formed gas-diffusion electrode (GDE), with a remarkably low silver loading of 0.2 mg cm −2 , showed a peak performance of jCO ≈ 385 mA cm −2 at around −1.0 V vs RHE and stable operation with high FECO (> 96%) at jTotal = 300 mA cm −2 over a 4 h run. These results demonstrate that the MOF-mediated approach offers a facile route to manufacture uniformly dispersed Ag catalysts for CO2ER by eliminating the need for illdefined deposition steps (drop-casting etc.), while allowing control of the catalyst structure through self-assembly.

Methanol synthesis by means of direct CO 2 hydrogenation has the potential to contribute to climate change mitigation by turning the most important greenhouse gas into a commodity. However, for this process to become industrially relevant, catalytic systems with improved activity, selectivity and stability are required. Here we explore the potential of metal-organic frameworks (MOF) as precursors for synthesis of Co 3 O 4 -supported In 2 O 3 oxide composites for the direct CO 2 hydrogenation to methanol. Stepwise pyrolytic-oxidative decomposition of indium-impregnated ZIF-67(Co) MOF affords the formation of a nanostructured In 2 O 3 @Co 3 O 4 reticulated shell composite material able to reach a maximum methanol production rate of 0.65 g MeOH •g cat -1 •h -1 with selectivity as high as 87% over 100 h on stream. Textural characteristics of the sacrificial ZIF-67(Co) matrix and In-loading were found to be important variables for optimizing the catalyst performance such as induction time, methanol productivity and selectivity. The structural investigation on the catalytic system reveals that the catalyst undergoes reorganization under reaction conditions, transforming from a Co 3 O 4 with amorphous In 2 O 3 shell into Co 3 InC 0.75 covered by a layer consisting of a mixture of amorphous CoO x and In 2 O 3 oxides. Structural reorganization is responsible for the observed induction period, while the amorphous mixed cobalt indium oxide shell is responsible for the high methanol yield and selectivity. Additionally, these results demonstrate the tunable performance of MOF-derived In 2 O 3 @Co 3 O 4 catalyst as a function of the reaction conditions which allows to establish a reasonable trade-off between high methanol yield and selectivity in a wide temperature and pressure window.

The production of carbon-neutral fuels from CO2 presents an avenue for causing an appreciable effect in terms of volume toward the mitigation of global carbon emissions. To that end, the production of isoparaffin-rich fuels is highly desirable. Here, we demonstrate the potential of a multifunctional catalyst combination, consisting of a methanol producer (InCo) and a Zn-modified zeolite beta, which produces a mostly isoparaffinic hydrocarbon mixture from CO2 (up to ∼85% isoparaffin selectivity among hydrocarbons) at a CO2 conversion of >15%. The catalyst combination was thoroughly characterized via an extensive complement of techniques. Specifically, operando X-ray absorption spectroscopy (XAS) reveals that Zn (which plays a crucial role of providing a hydrogenating function, improving the stability of the overall catalyst combination and isomerization performance) is likely present in the form of Zn6O6 clusters within the zeolite component, in contrast to previously reported estimations.

Figure 4. Characterization of red mud and red mud promoted with 2wt% of Ka fter reaction at 350 8C, 30 bar,and 50 hT OS:a)XRD results of iron-containing phaseso fsamples beforeand after catalytic reaction (PDF 01-089-0596, PDF 04-012-7038,a nd PDF 04-014-4562 diffractogramsw ere used for hematite, magnetite,a nd iron carbidep hases, respectively). b) 308-508 2q region of samples before and after catalytic reaction. c) XPS analysis results of samples before and after catalyticreaction.

The direct hydrogenation of CO 2 to higher alcohols has the potential to turn the main contributor of global warming into a valuable feedstock. However, for this technology to become attractive, more efficient and, especially, selective catalysts are required. Here we present a high throughput study on the influence of different promoters on the CO 2 hydrogenation performance of RhÀ SiO 2 catalysts. Fe and K promoters were found to improve ethanol selectivity at the expense of undesired CH 4 . The best-performing catalyst, with a composition 2 wt.% K, 20 wt.% Fe, and 5 wt.% Rh, displays an EtOH selectivity of 16 % at CO 2 conversion level of 18.4 % and CH 4 selectivity of 46 %. The combination of different characterization techniques and catalyst screening allowed us to unravel the role of each catalyst component in this complex reaction mechanism.