Ultrafast Crystallization of Ordered Mesoporous Metal Oxides and Carbon from Block Copolymer Self‐Assembly and Joule Heating

Abstract

Conventional heat treatments to generate well‐ordered and crystalline mesoporous oxide and carbon structures are limited by long durations and annealing temperatures that can cause mesostructural collapse. This paper describes a facile strategy coupling block copolymer‐directed self‐assembly with high‐power Joule heating to form highly crystalline and well‐ordered mesoporous oxide and carbon nanostructures within second timeframes. The combined approach is compatible with various functional self‐assembled hybrid systems with a range of crystallization temperatures, generating mesoporous composites of γ‐Al2O3‐carbon, γ‐Al2O3/MgO‐carbon, and anatase‐TiO2‐carbon with p6mm symmetry, non‐close‐packed mesoporous carbon, as well as hierarchical mesoporous α‐Fe2O3‐carbon structures. Removing the polymer/carbon gives well‐defined, highly crystalline mesoporous all‐γ‐Al2O3 and all‐anatase‐TiO2 structures. Impregnation of chloroplatinic acid followed by Joule heating yields platinum nanoparticles decorated on the channel walls of mesoporous γ‐Al2O3‐carbon structures. The resultant Joule‐heating‐induced well‐ordered crystalline mesoporous oxide and oxide‐carbon structures have high thermal and structural stabilities and exhibit better performances in CO2 adsorption capacity and lithium‐ion batteries than conventional heat‐treated counterparts. This approach represents an energy‐efficient and time‐saving route toward ordered porous materials with high surface area and pore accessibility for a wide range of environmental applications such as carbon sequestration, renewable energy storage, and environmental filtration.

Fabrication of PtIrPd Noble Metal Medium Entropy Alloy Thin Film by Atomic Layer Deposition

“…[36][37][38] EJH of PtIrPd Thin Film: The custom-built electric Joule heating setup and heating parameters have been described elsewhere. [43,44] Briefly, as-deposited PtIrPd thin films on sapphire were placed on top of a carbon felt (Fuel Cell Earth) under mild vacuum conditions (<1 Torr). The alloy film samples were then heated at 785, 980, and 1145 °C, respectively, with a 3 s ramp dwell followed by an annealing dwell of 5 s.…”

“…[41] EJH is an ultrafast heating approach that promotes accelerated interatomic diffusion at high temperatures while kinetically inhibiting phase separation within the few-second-timescale process window. [42][43][44] Hence, we conducted the sequential ALD growth of metal components layerby-layer (i.e., Pt, Ir, and Pd), followed by the EJH post-treatment to obtain homogenous MEA thin films, as shown in Figure 1. PtIrPd MEA thin films with a thickness of %20 nm and an atomic ratio of 35:35:30 at 980 °C were obtained after 5 s EJH.…”

Laser annealing-induced phase transformation behaviors of multicomponent metal alloy, oxide and nitride nanoparticle combinations

“…3 Rapid "shock" synthesis approaches have been explored to prevent phase segregation in nanostructures of multicomponent metal, oxide and nitride (MC-M/O/N) by rapid heating and quenching of the systems to throttle atomic diffusion. Recent examples include electrical/microwave-induced Joule heating methods using a stable conductive carbon substrate as heat transfer medium under inert environments to prevent oxidation and unsafe radiation exposure 28,40,41 . Rapid electrodeposition of emulsion droplets of metal salt precursors on carbon electrodes induced the formation of large sub-micrometer glassy MCM particles 42 .…”

One-Pot Synthesis of Aminated Bimodal Mesoporous Silica Nanoparticles as Silver-Embedded Antibacterial Nanocarriers and CO2 Capture Sorbents

“…Mesoporous inorganic materials with ordered architectures, high surface area and pore volume, tailorable pore size and pore size distribution, and tunable composition and surface chemistry have stimulated widespread interest in various applications of catalysis, , separation, , optics, energy generation and storage, − biomedical, − farming, and semiconductor nanostructures. − Mesoporous silica materials are especially well explored as a model system for sol–gel chemistry , and are known for their versatility to generate periodic/quasicrystalline nanoarchitectures and pore geometries in various macroscopic forms (e.g., nanoparticles, films, and monoliths), − as well as serving as nanocasting templates to access other functional materials. ,, Owing to all of these structural features, mesoporous silica nanoparticles (MSNs) are highly sought after in drug delivery, diagnostics, and sensing applications. − , …”