유필진 교수

A series of TiO(2)-reduced graphene oxide (RGO) nanocomposites were prepared by simple one-step hydrothermal reactions using the titania precursor, TiCl(4) and graphene oxide (GO) without reducing agents. Hydrolysis of TiCl(4) and mild reduction of GO were simultaneously carried out under hydrothermal conditions. While conventional approaches mostly utilize multistep chemical methods wherein strong reducing agents, such as hydrazine, hydroquinone, and sodium borohydride are employed, our method

Abstract Electroreduction of small molecules such as H 2 O, CO 2 , and N 2 for producing clean fuels or valuable chemicals provides a sustainable approach to meet the increasing global energy demands and to alleviate the concern on climate change resulting from fossil fuel consumption. On the path to implement this purpose, however, several scientific hurdles remain, one of which is the low energy efficiency due to the sluggish kinetics of the paired oxygen evolution reaction (OER). In response,

Physically self-assembled microstructures can be realized by utilizing the stress relief process in buckling that usually leads to the formation of random wrinkles. This physical self-assembly occurs when the wrinkle formation is guided by a periodic pattern on an elastomeric mold that is simply placed on the surface of a bilayer of metal on polymer, which is then heated above its glass-transition temperature (see Figure and inside cover).

With growing interest in the photocatalytic performance of TiO2-graphene composite systems, the ternary phase of TiO2, graphene, and Ag is expected to exhibit improved photocatalytic characteristics because of the improved recombination rate of photogenerated charge carriers and potential contribution of the generation of localized surface plasmon resonance at Ag sites on a surface of the TiO2-graphene binary matrix. In this work, Ag-TiO2-reduced graphene oxide ternary nanocomposites were succes

The design and synthesis of cellular structured materials are of both scientific and technological importance since they can impart remarkably improved material properties such as low density, high mechanical strength, and adjustable surface functionality compared to their bulk counterparts. Although reducing the density of porous structures would generally result in reductions in mechanical properties, this challenge can be addressed by introducing a structural hierarchy and using mechanically

In this study, we present a facile means of fabricating graphene thin films via layer-by-layer (LbL) assembly of charged graphene nanosheets (GS) based on electrostatic interactions. To this end, graphite oxide (GO) obtained from graphite powder using Hummers method is chemically reduced to carboxylic acid-functionalized GS and amine-functionalized GS to perform an alternate LbL deposition between oppositely charged GSs. Specifically, for successful preparation of positively charged GS, GOs are

When multiple intermolecular interactions occur simultaneously, complexed molecules undergo gelation by inter-cohesive bonding, inducing a pseudo-crosslinking effect to form a supramolecular gel. Among the number of substances that can induce supramolecular assembly, phenolic species such as 3,4-dihydroxy-l-phenylalanine (DOPA) are widely utilized for synthesizing adhesive materials. However, despite the strong adhesion capability of monomeric phenol, it lacks cohesive strength and rarely forms

Varied morphologies and compositions of bismuth tungstate nanocomposites have been investigated as promising materials for photocatalytic applications. Among these nanocomposites, hierarchically structured bismuth sulfide (Bi 2 S 3 )/bismuth tungstate (Bi 2 WO 6 ) hybrids have significant photocatalytic efficiency toward heavy metal ions. To simplify the synthetic procedure for this desirable composite, we developed a robust single-step hydrothermal synthesis for the formation of hierarchically

We report the full spectrum of the evolution of the wrinkle pattern formation in a thin bilayer film of an elastic metal on a viscoelastic polymer. Although the origin is different, the transition of an initial islandlike pattern to a labyrinthine structure without any change in the wavelength (q approximately t(0)) and the overall evolutionary process is strikingly similar to that in the spinodal system but the process is robust and takes place on a long time scale (about 10 days). The change i

MXene-supported CoP and Co₇Se₈ catalysts showed enhanced water-splitting activity. The oxidation process of the anion components (P and Se) of the hybrid catalysts, under OER conditions, significantly influenced the activity and stability.

Modulus-tunable ultraviolet (UV) curing molds allow not only physical patterning of imprinting but also chemical patterning of microcontact printing. The mechanical properties of the mold can be tailored by the chain length of an acrylate modulator in the cross-linking reaction. This tunability can be utilized to obtain a proper balance that is needed for a given patterning technique between the rigidity requirement (tensile modulus = 320 MPa) of a mold for patterning a fine structure and the fl

Because of the salient impact on the performance of oxygen evolution reaction (OER), the surface dynamics of precatalysts accompanying the surface oxidation and dissolution of catalytic components demands immense research attention. Accordingly, the change in the structural integrity under high current density generally results in inconsistent OER performances. To address this challenge, here, we present the intricate design of precatalysts, strategically followed by reconstruction treatment in

P is a mediator- and co-catalyst-free photocatalyst system. The improved photocatalytic efficiency obtained with this system compared to other ZBC systems assisted by mediators and co-catalysts establishes the critical importance of interfacial solid-solid contact and the well-balanced position of energy levels for solar-water splitting. The promising solar-water splitting under optimum composition conditions highlighted the relationship between effective charge separation and composition.