Ulsan National Institute of Science and Technology · Materials Science
Professor Javeed Mahmood's research lab specializes in the design, synthesis, and characterization of advanced two-dimensional (2D) nanomaterials with tailored electronic and catalytic properties. The lab focuses on developing novel covalent organic frameworks (COFs), nitrogen-doped carbon-based materials like C2N, and conductive polymers such as polyaniline and polypyrrole for applications in energy conversion and storage. Key research directions include the rational design of efficient electrocatalysts for hydrogen evolution and borohydride-based hydrogen generation, as well as exploring the integration of transition metals into 2D frameworks to enhance catalytic performance. The lab combines advanced synthesis techniques with in-depth characterization using scanning tunneling microscopy, X-ray diffraction, and spectroscopic methods to achieve atomic-level understanding of material structures and functions.
Figures are computed from collected data and may differ slightly.
Recent graphene research has triggered enormous interest in new two-dimensional ordered crystals constructed by the inclusion of elements other than carbon for bandgap opening. The design of new multifunctional two-dimensional materials with proper bandgap has become an important challenge. Here we report a layered two-dimensional network structure that possesses evenly distributed holes and nitrogen atoms and a C2N stoichiometry in its basal plane. The two-dimensional structure can be efficient
The formation of 2D polyaniline (PANI) has attracted considerable interest due to its expected electronic and optoelectronic properties. Although PANI was discovered over 150 y ago, obtaining an atomically well-defined 2D PANI framework has been a longstanding challenge. Here, we describe the synthesis of 2D PANI via the direct pyrolysis of hexaaminobenzene trihydrochloride single crystals in solid state. The 2D PANI consists of three phenyl rings sharing six nitrogen atoms, and its structural u
With cobalt oxides as promising catalysts for hydrogen generation, 2D network polymer-supported cobalt-oxide catalysts with good crystallinity are highly anticipated to enhance catalytic performance. Here we report the fabrication of a 2D nitrogenated network polymer-encapsulated cobalt-oxide (Co@C2N) catalyst via an in situ solvothermal synthesis. Co@C2N exhibits outstanding catalytic activities for hydrogen (H2) generation from the hydrolysis of alkaline sodium borohydride (NaBH4) solutions. T
Developing efficient and durable electrocatalysts is key to optimizing the electrocatalytic hydrogen evolution reaction (HER), currently one of the cleanest and most sustainable routes for producing hydrogen. Here, a unique and efficient approach to fabricate and embed uniformly dispersed Ir nanoparticles in a 3D cage-like organic network (CON) structure is reported. These uniformly trapped Ir nanoparticles within the 3D CON (Ir@CON) effectively catalyze the HER process. The Ir@CON electrocataly
Ordered two-dimensional covalent organic frameworks (COFs) have generally been synthesized using reversible reactions. It has been difficult to synthesize a similar degree of ordered COFs using irreversible reactions. Developing COFs with a fused aromatic ring system via an irreversible reaction is highly desirable but has remained a significant challenge. Here we demonstrate a COF that can be synthesized from organic building blocks via irreversible condensation (aromatization). The as-synthesi
Hybrid polypyrrole (PPy) nanoparticles were prepared using a low-temperature oxidative polymerization process in an acidic solution with polyethyleneimine (PEI) as a template and amine source. The results showed that the nanoparticles have an amorphous structure in the X-ray diffractogram and exhibited good dispersibility in water, uniform size, and a specific conductivity ranging from 0.1 to 6.9 S/cm. The particle size could be tuned from 85 to 300 nm by varying the reactant concentration. Undo
A three-dimensional (3D) cage-like organic network (3D-CON) structure synthesized by the straightforward condensation of building blocks designed with gas adsorption properties is presented. The 3D-CON can be prepared using an easy but powerful route, which is essential for commercial scale-up. The resulting fused aromatic 3D-CON exhibited a high Brunauer-Emmett-Teller (BET) specific surface area of up to 2247 m<sup>2</sup> g<sup>-1</sup> . More importantly, the 3D-CON displayed outstanding low
Fused aromatic network (FAN) structures are a category of ordered porous polymers that permit the specific fusion of building blocks into extended porous network structures with designed skeletons and pores. One significant feature of FANs is that their structures can be tailorable with fused aromatic rings without rotatable single-bond connectivity. As a result, the geometry and space orientation of the building blocks are easily incorporated to guide the topological expansion of the architectu
Recently, studies of 2D organic layered materials with unique electronic properties have generated considerable interest in the research community. However, the development of organic materials with functional electrical transport properties is still needed. Here, a 2D fused aromatic network (FAN) structure with a C<sub>5</sub> N basal plane stoichiometry is designed and synthesized, and thin films are cast from C<sub>5</sub> N solution onto silicon dioxide substrates. Then field-effect transist
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