Three-dimensionally ordered macroporous (3DOM) ZnO-CeO 2 -Al 2 O 3 (MMO)@ZIF-8 was synthesized via a vapor-phase pseudomorphic transformation from 3DOM MMO and 2-methylimidazole that maintained the periodic, interconnected pore structure of the starting material, even for relatively small (190 nm diameter) macropores. After structural optimization via the synthesis conditions, this simple, solvent-free method resulted in a thin, uniform ZIF-8 shell on the 3DOM skeleton with a capacity of 47 mg/g for Rhodamine B (RhB) dye adsorption. The 3DOM MMO@ZIF-8 composite material was suitable for monitoring the reactivity and stability of ZIF-8 in different solvent systems simply and effectively by using the included crystalline CeO 2 phase as an internal standard for comparing powder X-ray diffraction (XRD) intensities after dye adsorption steps. By taking advantage of the internal standard, it was clearly shown that ZIF-8 dissolves slowly during dye adsorption in an aqueous system, exposing new adsorption sites during recycling. This behavior benefits the reuse of the ZIF-8 adsorbent during a few cycles, but leads to adsorbent loss in the long run.

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Nanopore-driven sequestration of ionic liquids from a silicone membrane is presented, a phenomenon that has not been reported previously. Reference electrodes with ionic liquid doped polydimethylsiloxane (PDMS) reference membranes and colloid-imprinted mesoporous carbon (CIM) as solid contact are not functional unless special attention is paid to the porosity of the solid contact. In the fabrication of such reference electrodes, a solution of a hydroxyl-terminated silicone oligomer, ionic liquid, cross-linking reagent, and polymerization catalyst is deposited on top of the carbon layer, rapidly filling the pores of the CIM carbon. The catalyzed polymerization curing of the silicone quickly results in cross-linking of the hydroxyl-terminated polydimethylsiloxane oligomers, forming structures that are too large to penetrate the CIM carbon pores. Therefore, as solvent evaporation from the top of freshly prepared membranes drives the diffusional transport of solvent toward that membrane surface, the solvent molecules that leave the CIM carbon pores can only be replaced by the ionic liquid. This depletes the ionic liquid in the reference membrane that overlies the CIM carbon solid contact and increases the membrane resistance by up to 3 orders of magnitude, rendering the devices dysfunctional. This problem can be avoided by presaturating the CIM carbon with ionic liquid prior to the deposition of the solution that contains the silicone oligomers and ionic liquid. Alternatively, a high amount of ionic liquid can be added into the membrane solution to account for the size-selective sequestration of ionic liquid into the carbon pores. Either way, a wide variety of ionic liquids can be used to prepare PDMS-based reference electrodes with CIM carbon as a solid contact. A similar depletion of the K+ ionophore BME-44 from ion-selective silicone membranes was observed too, highlighting that the depletion of active ingredients from polymeric ion-selective and reference membranes due to interactions with high surface area solid contacts may be a more common phenomenon that so far has been overlooked.

The glucose sensitivity achieved with copper(II) oxide particles with three different morphologies (spheres, platelets, and needles) for application in nonenzymatic glucose sensors was investigated. The morphologies of CuO nanoparticles were controlled by different synthesis parameters, including changes in precipitators of Cu(II) ions, pH values, calcination protocol, and the addition of surfactant and hydrogen peroxide. The role of copper(II) oxide particle morphology in nonenzymatic glucose sensing was studied. The primary driving factor in the electrocatalytic process was investigated for several morphological properties of the material. We studied the effects of exposed crystal faces, specific surface area, pore volume, and grain size of copper oxides on glucose sensitivity. This study showed that the electrocatalytic performance in glucose sensing correlates primarily with the grain size of copper oxide nanoparticles and the capacitance introduced therefrom. The needle-shaped CuO nanoparticles presented the optimal morphology in this application, resulting in good sensitivity to glucose (2.05 mA·mM–1·cm–2), a linear range of 0.05–5 mM glucose, and the best long-term stability among these materials. This work provides insight into the potential use of CuO-based materials in biosensors and into the major contributing factors of metal oxide-based nanoparticles in sensing applications.

Silver nanobelts (AgNBs) have attracted a great interest due to their excellent electrical conductivity and mechanical strength, leading a facile synthesis of these AgNBs in great demand. In here, we are reporting a simple, aqueous phase, size tunable synthesis of smooth surfaced 1D-silver nanobelts using a Polyaniline (PANi) derived polymer at room temperature. The specifically designed PANi polymer, comprising a pendant carboxyl group in the chain, acted as both a reducing agent and template. The resulting Ag nanobelts have more than 10 μm of length, mean width values ranging from 41.1 (11.5) nm to 118.5 (8.8) nm and a mean thickness value of 36.7 (12.5) nm. The UV-Visible spectrum of the AgNBs has shown two Surface Plasmon Resonance peaks at 352 nm and 383 nm.