Tohoku University · Materials Science
Mingwei Chen 교수의 연구실은 나노소재의 기계적 거동과 에너지 응용을 중심으로 한 다학제적 연구를 수행합니다. 특히 나노크리스탈린 알루미늄의 변형 기계 메커니즘, 다기능성 나노다공구 그래핀을 활용한 고효율 태양열 증기 생성, 그리고 다양한 도핑을 통한 그래핀 기반 촉매 개발(예: HER, ORR)에 초점을 맞추고 있습니다. 이들의 연구는 나노스케일에서의 원자 구조와 전자적 특성의 상관관계를 규명하며, 에너지 변환 및 저장 응용에 기여하고 있습니다.
Figures are computed from collected data and may differ slightly.
We report transmission electron microscope observations that provide evidence of deformation twinning in plastically deformed nanocrystalline aluminum. The presence of these twins is directly related to the nanocrystalline structure, because they are not observed in coarse-grained pure aluminum. We propose a dislocation-based model to explain the preference for deformation twins and stacking faults in nanocrystalline materials. These results underscore a transition from deformation mechanisms co
Multifunctional nanoporous graphene is realized as a heat generator to convert solar illumination into high-energy steam. The novel 3D nanoporous graphene demonstrates a highly energy-effective steam generation with an energy conversation of 80%.
Chemical doping has been demonstrated to be an effective way to realize new functions of graphene as metal-free catalyst in energy-related electrochemical reactions. Although efficient catalysis for the oxygen reduction reaction (ORR) has been achieved with doped graphene, its performance in the hydrogen evolution reaction (HER) is rather poor. In this study we report that nitrogen and sulfur co-doping leads to high catalytic activity of nanoporous graphene in HER at low operating potential, com
Single-atom nickel dopants anchored to three-dimensional nanoporous graphene can be used as catalysts of the hydrogen evolution reaction (HER) in acidic solutions. In contrast to conventional nickel-based catalysts and graphene, this material shows superior HER catalysis with a low overpotential of approximately 50 mV and a Tafel slope of 45 mV dec(-1) in 0.5 M H2SO4 solution, together with excellent cycling stability. Experimental and theoretical investigations suggest that the unusual catalyti
The widespread enthusiasm for research on bulk metallic glasses is driven by both a fundamental interest in the structure and properties of disordered materials and their unique promise for structural and functional applications. Unlike the case for crystalline materials, the disordered and nonequilibrium nature of metallic glasses causes their underlying deformation mechanisms to be poorly known. A definite correlation between mechanical behavior and the atomic/electronic structures of metallic
Nanoporous bimetallic (Co<sub>1−x</sub>Fe<sub>x</sub>)<sub>2</sub>P phosphides with tuneable Co/Fe ratios exhibit versatile catalytic activities for highly efficient electrochemical water splitting.
High-resolution electron microscope observations of shock-loaded boron carbide have revealed the formation of nanoscale intragranular amorphous bands that occur parallel to specific crystallographic planes and contiguously with apparent cleaved fracture surfaces. This damage mechanism explains the measured, but not previously understood, decrease in the ballistic performance of boron carbide at high impact rates and pressures. The formation of these amorphous bands is also an example of how shoc
The "edge-free" monolayer MoS2 films supported by 3D nanoporous gold show high catalytic activities towards hydrogen evolution reaction (HER), originating from large out-of-plane strains that are geometrically required to manage the 3D curvature of bicontinuous nanoporosity. The large lattice bending leads to local semiconductor-to-metal transition of 2H MoS2 and the formation of catalytically active sites for HER.
Electrochemical energy storage: The performance of MnO2 as a pseudo-capacitive material was enhanced by doping electrodeposited MnO2 with physically deposited gold atoms (see picture). The resulting MnO2 electrodes showed an enhanced electronic conductivity and a remarkable stability under voltammetric cycling. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery
Shear bands generally initiate strain softening and result in low ductility of metallic glasses. In this Letter, we report high-resolution electron microscope observations of shear bands in a ductile metallic glass. Strain softening caused by localized shearing was found to be effectively prevented by nanocrystallization that is in situ produced by plastic flow within the shear bands, leading to large plasticity and strain hardening. These atomic-scale observations not only well explain the extr
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