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We report an investigation into the magnetic and electronic properties of partially hydrogenated vertically aligned few layers graphene (FLG) synthesized by microwave plasma enhanced chemical vapor deposition. The FLG samples are hydrogenated at different substrate temperatures to alter the degree of hydrogenation and their depth profile. The unique morphology of the structure gives rise to a unique geometry in which graphane/graphone is supported by graphene layers in the bulk, which is very different from other widely studied structures such as one-dimensional nanoribbons. Synchrotron based x-ray absorption fine structure spectroscopy measurements have been used to investigate the electronic structure and the underlying hydrogenation mechanism responsible for the magnetic properties. While ferromagnetic interactions seem to be predominant, the presence of antiferromagnetic interaction was also observed. Free spins available via the conversion of sp2 to sp3 hybridized structures, and the possibility of unpaired electrons from defects induced upon hydrogenation are thought to be likely mechanisms for the observed ferromagnetic orders.

We report on studies of physical properties of the two compounds CeFe2Al8 and CeCo2Al8 in which we have found varying degrees of electronic correlational phenomena. No magnetic ordering was detected down to 0.4 K in either of the two compounds. At elevated temperatures an incoherent Kondo interaction between the Ce 4f -electron and the conduction electrons is prevalent in both compounds. CeCo2Al8 exhibits a stable 4f -electron magnetic moment, but in CeFe2Al8 an intermediate-valent state prevails near room temperature that eventually transforms into a Fermi-liquid ground state. The low-temperature specic heat of CeCo2Al8 shows typical strongly correlated electron behaviour and a − log T upturn in its electronic specic heat below about 10 K.

The compound PrFe2Al8 possesses a three-dimensional network structure resulting from the packing of Al polyhedra centered at the transition metal element Fe and the rare earth Pr. Along the c-axis, Fe and Pr form chains which are separated from each other by the Al-network. In this paper, the magnetism and crystalline electric field effects in PrFe2Al8 are investigated through the analysis of magnetization and specific heat data. A magnetic phase transition in the Pr lattice is identified at T P r N ≈ 4 K in dc magnetization and ac susceptibility data. At 2 K, the magnetization isotherm presents a ferromagnetic saturation, however, failing to reach full spinonly ferromagnetic moment of Pr 3+ . Metamagnetic step-like low-field features are present in the magnetization curve at 2 K which is shown to shift upon field-cooling the material. Arrott plots centered around T P r N display "S"-like features suggestive of an inhomogeneous magnetic state. The magnetic entropy, Sm, estimated from specific heat outputs a value of R ln(2) at TN2 suggesting a doublet state for Pr 3+ . The magnetic specific heat is modeled by using a 9-level Schottky equation pertinent to the Pr 3+ ion with J = 4. Given the crystalline electric field situation of Pr 3+ , the inference of a doublet state from specific heat and consequent long-range magnetic order is an unexpected result.

Polymeric form of graphitic carbon nitride (CN) has attracted much attention in recent years because of their performance as a support material of various reactions. Here, we report the fabrication of CN and gold nanoparticle-decorated CN system for electrochemical methanol oxidation process. The microscopic, optical, thermal, and surface properties of the synthesized materials have been analyzed using different characterization techniques. Both the synthesized materials were successfully used as electrocatalyst for methanol oxidation reaction under the alkaline media. The stability and the tolerance of the synthesized catalysts have been studied, in connection with the title reaction, on the basis of oxophilicity of the gold. The strong coordination between gold nanoparticles and amine groups of CN facilitates the electron transfer from amine to metal, which makes the gold particles more electron rich and consequently makes the Au-CN system more active for electrocatalytic methanol oxidation reaction.