This review covers recently reported polymer composites that show a thermoelectric (TE) effect and thus have potential application as thermoelectric generators and Peltier coolers. The growing need for CO2-minimizing energy sources and thermal management systems makes the development of new TE materials a key challenge for researchers across many fields, particularly in light of the scarcity or toxicity of traditional inorganic TE materials based on Te and Pb. Recent reports of composites with inorganic and organic additives in conjugated and insulating polymer matrices are covered, as well as the techniques needed to fully characterize their TE properties.

Strategies for interpreting mass spectrometric and Raman spectroscopic data have been developed to study the structure and reactivity of uranyl peroxide cage clusters in aqueous solution. We demonstrate the efficacy of these methods using the three best-characterized uranyl peroxide clusters, {U24}, {U28}, and {U60}. Specifically, we show a correlation between uranyl-peroxo-uranyl dihedral bond angles and the position of the Raman band of the symmetric stretching mode of the peroxo ligand, develop methods for the assignment of the ESI mass spectra of uranyl peroxide cage clusters, and show that these methods are generally applicable for detecting these clusters in the solid state and solution and for extracting information about their bonding and composition without crystallization.

Sunlight photolysis of uranyl nitrate and uranyl acetate solutions in pyridine produces uranyl peroxide complexes. To answer longstanding questions about the origin of these complexes, we conducted a series of mechanistic studies and demonstrate that these complexes arise from photochemical oxidation of water. The peroxo ligands are easily removed by protonolysis, allowing regeneration of the initial uranyl complexes for potential use in catalysis.

Polymer composites containing carbon nanoparticles have recently garnered much attention due to superb electronic, mechanical, and gas barrier properties. Graphene oxide (GO) and reduced graphene oxide (rGO) stand out among carbon nanofillers due to cost efficiency and scalability, but one hurdle preventing their widespread use is the lack of miscibility of GO and rGO platelets with polymer matrixes. The desired processability can be achieved by covalent functionalization of GO and rGO, but current methods necessitate anhydrous conditions and harsh reagents. Herein, we describe the rapid covalent functionalization of GO and rGO in acidic aqueous suspensions under ambient conditions using the Pinner reaction between hydroxyl groups on (r)­GO and nitriles. The modified platelets are characterized by FTIR, Raman, AFM, TGA, XPS, and four-point probe conductivity measurements. Using this methodology, GO requires little purification and no drying after preparation and multiple grams can be functionalized with a variety of small molecule and polymer nitriles in only a couple of hours. Furthermore, functionalized platelets are isolated by centrifugation or filtration, readily giving conductive platelets with tailored solubility and functionalities for further modification.

Graphene oxide (GO) is selectively functionalized on one face to prepare Janus platelets which are characterized by various spectroscopic and microscopic techniques. With this methodology, Janus GO platelets can be prepared without the use of a solid substrate and the two platelet faces can be orthogonally modified in a one-pot reaction.