In this work we synthesized two novel isostructural twin hybrids Comp1: [H(CHN)Cu][PMoO] & Comp2: [H(CHN)Cu][PWO], based on the Keggin ions (PMoO & PWO), Cu(I) cation, and 4,4'-bipyridine, by in situ hydrothermal reduction of Cu, facilitated through extensive standardizations of synthetic pH conditions. Both compounds crystallized in monoclinic P2/ c space group with similar lattice parameters and crystal structures. The structural similarity prompted us to explore comparative catalytic properties of the hybrids, to understand the relative role of the POM species in the activity. While characterization techniques like powder X-ray diffraction (XRD), single-crystal XRD, IR, adsorption studies, etc. confirmed the identical structural hierarchy in the twin polyoxometalate-based metal organic frameworks (POMOFs), critical analyses through X-ray photoelectron spectroscopy, X-ray absorption near-edge structure spectroscopy, and magnetic property studies elucidated the electronic and local structural properties of the two. The hybrids were highly active for heterogeneous catalysis of small-molecule oxidation, with Comp 2 showing better activity than Comp1, particularly for oxidation of ethylbenzene and cyclooctene. Comp2 also outperformed Comp1 in photocatalytic degradation of methylene blue, with higher conversion efficiency of 83% and one order higher apparent rate constant of 0.0139 min, which is comparable to that of the well-known photocatalyst, P25. Electrochemical pseudocapacitance studies revealed that these POMOFs are having the potential to act as good charge storage and conducting devices if their electrochemical stability can be improved.

CeO2 nanoboxes designed by controlling various chemical parameters enhance both the efficiency and stability of Pt nanoparticles towards the electrochemical oxidation of formic acid.

Pd17Se15 nanoparticles have been synthesized by a one-pot colloidal synthesis method. An accelerated degradation test confirms the ultra-high stability of the catalyst which gets enhanced after 50 000 cycles.

Understanding the descriptors of electrochemical activity and ways to modulate them are of paramount importance for the efficient structural engineering of electrocatalysts. Although, many studies separately elucidated the significance of...

In-depth insight into oxygen reduction reaction (ORR) electrocatalyst with high figures of merit (activity, stability, and selectivity) is highly crucial to rationally design electrocatalyst with a potential to replace state-of-the-art Pt/C. This work reports the synthesis of CoPd 2 Se 2 nanoparticles that show remarkably high stability of 50000 electrochemical cycles toward ORR. Morphology of the particles is characterized using SEM and TEM microscopy techniques and simulated using Bravais−Friedel−Donay−Harker (BFDH) morphology calculation method. A deconvoluted approach was used to understand the role of each element in the compound. DFT calculation was performed to have an in-depth analysis of the active site. Co and Pd provided an active site for the O 2 adsorption and Pd dissociates the OO bond. The back-donation of substantial electron density to the π* antibonding orbital of the molecule expedites the 4e-reduction of O 2 throughout the entire potential range. During the electrochemical stability test, Se forms a protective layer and prevents the active Co and Pd sites from OH poisoning.

The authors report the detailed growth characterization of a molecular layer deposition chemistry that utilizes a cyclic azasilane, maleic anhydride, and water in a sequential reaction sequence. They observe a three stage growth for this chemistry during which the growth rate per cycle (GPC) is initially small and increases to large steady state values. Using a quartz crystal microbalance, they observe significant diffusion of maleic anhydride and cyclic azasilane into the film that causes the large GPC. They also observe that longer purge times between precursor exposures result in a smaller GPC and an increased number of cycles required to reach steady state and large GPCs. At higher substrate temperatures, growth is suppressed due to precursor desorption. Furthermore, after long inert gas purging after film growth, significant film mass loss occurs accompanied by a loss of porosity indicated by the lack of film absorption of maleic anhydride and cyclic azasilane precursors after restarting growth. They conclude that growth using this specific chemistry is largely dominated by precursor absorption and diffusion within the film, resulting in CVD-like reactions, rather than sequential, self-limiting surface reactions.

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Thermal processing of molecular layer deposited (MLD) hybrid inorganic−organic alucone thin films produced porous and low-k materials. Alucone films were deposited by MLD using trimethyl aluminum and ethylene glycol at 120 °C. Changes in the film density and thickness during annealing were monitored using in-situ X-ray reflectivity and were compared to atomic layer deposited (ALD) alumina films. The chemical evolution of the as-deposited and annealed alucone films during post-deposition heating with and without UV was probed using infrared spectroscopy, Rutherford backscattering, nuclear reaction analysis, and 15 N spectroscopy, providing a detailed understanding of the induced changes. The concentration of OH groups decreased after depositing 1 nm of alumina capping layer as a barrier to moisture uptake, which also decreased the etch rate in CF 4 /O 2 plasma. The lowest dielectric constant of the processed alucone films (k min = 4.75) was 25% lower than the lowest values measured in ALD alumina counterparts (k min = 6.7). Large thickness decreases for alucone films were observed at ∼200 °C of anneal temperatures. Removal of retained organic components by thermal processing of MLD films is demonstrated to be a promising and versatile route to porous thin films for a wide range of applications including low dielectric constant materials.