Homogeneous catalysts (“mediators”) are useful for tuning selectivity in organic electrosynthesis. However, they can have a negative impact on the overall mass and energy balance if used only once or recycled inefficiently. In a previous work, we introduced the polymediator concept, in which soluble redox‐active polymers catalyze the electrochemical reaction, allowing for recovery by dialysis or pressure‐driven membrane filtration. Using anodic alcohol oxidation as a test case, it was shown that TEMPO‐modified polymethacrylates (TPMA) can serve as efficient and reusable mediators. In the present study, the properties of a TPMA sample with well‐defined molecular weight distribution were studied using cyclic voltammetry and compared to low‐molecular TEMPO species. The non‐catalytic profiles of TPMA are shaped by diffusive and adsorptive processes, whereby the latter only become pronounced at low mediator concentrations and high scan rates. Electrocatalytic studies suggest that under the applied conditions, TPMA‐catalyzed alcohol oxidation is a predominantly homogeneous process. The homogeneous kinetics are determined rather by the mediator potential than by steric influences of the polymer backbone.

Methods for synthesis of zinc oxide hydrosols by peptization and condensation were developed. The basic colloid-chemical properties of the sols were determined: electrokinetic properties, size and phase composition of particles, and stability of hydrosols against introduction of electrolytes. The possibility of obtaining antibacterial and UV-protecting cosmetic preparations from the hydrosols obtained was demonstrated.Owing to the combination of diverse physical and chemical properties (high melting point and heat conductivity, ability to effectively absorb UV light, high photosensitivity, largely unique piezo-and pyroeffects, rather strong luminescence, etc.), zinc oxide ZnO is extensively used in a wide variety of industries. In particular, introduction of zinc oxide into cosmetic creams and gels makes them sunlight-protective and antibacterial [1]. The efficiency of their action largely depends not only on the concentration of the active substance, zinc oxide, but also on the size of its particles, their modification, and degree of polydispersity. In particular, the higher the dispersity of the particles, the more effective a preparation on their basis [2]. This means that the task of obtaining as fine particles of this oxide as possible is a matter of current interest.Here we demonstrate the possibility of synthesizing highly dispersed zinc oxide by the sol3gel method. This technique was chosen because it can yield nanomaterials with controlled polydispersity and prescribed particle size.We chose zinc nitrate as a precursor owing to its ready availability and nontoxicity. It should be noted that synthesis of nanodispersed ZnO by the sol3gel method has already been described in the literature [3,4], but the synthesis was performed from other materials (zinc alkoxides or organometallic compounds), whose use in cosmetology is prohibited. As for other ways to obtain zinc oxide, which are not based on the sol3gel technology, they can also be found in the literature, but are rather complicated and exotic (decomposition in an electric arc, laser evaporation of a target, etc. [5,6]). In view of the aforesaid, we suggest a rather easy procedure for preparing highly dispersed ZnO (in the form of a sol) by hydrolysis of Zn(NO 3 ) 2 . EXPERIMENTALThe hydrosol was synthesized by two methods, peptization and condensation. The concentration of all the sols was determined gravimetrically, both in a sol itself and in the ultrafiltrate obtained from the sol. The ultrafiltration was done in a standard cell equipped with polysulfone membranes. The size of sol particles was monitored by photon-correlation spectroscopy (PCS), using the known procedure [7]. The phase composition of sol particles was determined by X-ray diffraction analysis on a DRON-3 diffractometer with CuK a radiation (1.54051 A).In the peptization method, a hydroxide freshly precipitated from a nitrate solution with ammonia was washed with distilled water and then peptized either with an electrolyte (zinc nitrate) solution or with dilute nitric acid. It should b...

Invited for this month's cover picture is the group of Robert Francke at the Leibniz Institute for Catalysis (LIKAT Rostock). The cover picture illustrates the anodic oxidation of 4‐methoxybenzyl alcohol catalyzed by TEMPO‐modified polymethacrylate, one of the model reactions that was used to study the catalytic behavior of the polymediator. Two transformations are shown, one proceeding at the electrode surface (left) and one in solution (right), indicating that the electrocatalytic process comprises both homogeneous and heterogeneous contributions. Read the full text of the Article at 10.1002/celc.202100768.

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