scholarly journals Site-Specific Electrodeposition Enables Self-Terminating Growth of Atomically Dispersed Metal Catalysts

Author(s):  
Yi Shi ◽  
Wenmao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhongqiu Li ◽  
...  

<p>The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition (UPD) of a single-atom nonnoble metal onto the chalcogen atoms of chemically exfoliated transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition (SSED) enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this SSED methodology could be extended to the synthesis of a variety of ADMCs (for example, Pt, Pd, Rh, Cu, Pb, Bi, and Sn single atoms), showing its general scope for the large-scale production of functional ADMCs in heterogenous catalysis. </p>

2020 ◽  
Author(s):  
Yi Shi ◽  
Wenmao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhongqiu Li ◽  
...  

<p>The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition (UPD) of a single-atom nonnoble metal onto the chalcogen atoms of chemically exfoliated transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition (SSED) enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this SSED methodology could be extended to the synthesis of a variety of ADMCs (for example, Pt, Pd, Rh, Cu, Pb, Bi, and Sn single atoms), showing its general scope for the large-scale production of functional ADMCs in heterogenous catalysis. </p>


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi Shi ◽  
Wen-Mao Huang ◽  
Jian Li ◽  
Yue Zhou ◽  
Zhong-Qiu Li ◽  
...  

Abstract The growth of atomically dispersed metal catalysts (ADMCs) remains a great challenge owing to the thermodynamically driven atom aggregation. Here we report a surface-limited electrodeposition technique that uses site-specific substrates for the rapid and room-temperature synthesis of ADMCs. We obtained ADMCs by the underpotential deposition of a non-noble single-atom metal onto the chalcogen atoms of transition metal dichalcogenides and subsequent galvanic displacement with a more-noble single-atom metal. The site-specific electrodeposition enables the formation of energetically favorable metal–support bonds, and then automatically terminates the sequential formation of metallic bonding. The self-terminating effect restricts the metal deposition to the atomic scale. The modulated ADMCs exhibit remarkable activity and stability in the hydrogen evolution reaction compared to state-of-the-art single-atom electrocatalysts. We demonstrate that this methodology could be extended to the synthesis of a variety of ADMCs (Pt, Pd, Rh, Cu, Pb, Bi, and Sn), showing its general scope for functional ADMCs manufacturing in heterogeneous catalysis.


Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 601
Author(s):  
Dinh-Tuan Nguyen ◽  
Hsiang-An Ting ◽  
Yen-Hsun Su ◽  
Mario Hofmann ◽  
Ya-Ping Hsieh

The success of van-der-Waals electronics, which combine large-scale-deposition capabilities with high device performance, relies on the efficient production of suitable 2D materials. Shear exfoliation of 2D materials’ flakes from bulk sources can generate 2D materials with low amounts of defects, but the production yield has been limited below industry requirements. Here, we introduce additive-assisted exfoliation (AAE) as an approach to significantly increase the efficiency of shear exfoliation and produce an exfoliation yield of 30%. By introducing micrometer-sized particles that do not exfoliate, the gap between rotor and stator was dynamically reduced to increase the achievable shear rate. This enhancement was applied to WS2 and MoS2 production, which represent two of the most promising 2D transition-metal dichalcogenides. Spectroscopic characterization and cascade centrifugation reveal a consistent and significant increase in 2D material concentrations across all thickness ranges. Thus, the produced WS2 films exhibit high thickness uniformity in the nanometer-scale and can open up new routes for 2D materials production towards future applications.


2D Materials ◽  
2021 ◽  
Author(s):  
Kun Ye ◽  
Lixuan Liu ◽  
Liying Chen ◽  
Wenlong Li ◽  
Bochong Wang ◽  
...  

Abstract The layered transition metal dichalcogenides (TMDs) exhibit the intriguing physical properties and potential application in novel electronic devices. However, controllable growth of multilayer TMDs remains challenging. Herein, large-scale and high-quality multilayer prototype TMDs of W(Mo)Se2 were synthesized via chemical vapor deposition. For Raman and PL measurements, 2H and 3R multilayer WSe2 crystals displayed significant layer-dependent peak position and intensity feature. Besides, different from the oscillatory relationship of SHG intensity for odd-even layer numbers in 2H-stacked multilayer WSe2, the second harmonic generation intensity of 3R-stacked ones parabolically increased with the thickness due to the absence of inversion symmetry. For device application, photodetectors based on WSe2 with increasing thickness exhibited p-type (bilayer), ambipolar (trilayer), and n-type (4 layers) semiconductor behaviors, respectively. Furthermore, photodetectors based on the as-synthesized 3R-stacked WSe2 flakes displayed an excellent responsivity (R) of 7.8×103 mA/W, high specific detectivity (Da*) of 1.7×1014 Jones, outstanding external quantum efficiency (EQE) of 8.6×102 %, and fast response time (τRise=57 ms and τFall=53 ms) under 532 nm illumination with bias voltage of Vds=5 V. Similar results have also been achieved in multilayer MoSe2 crystals. All these findings indicate great potential of 3R-stacked TMDs in two-dimensional optoelectronic applications.


ACS Nano ◽  
2019 ◽  
Vol 13 (5) ◽  
pp. 5611-5615
Author(s):  
Peng Chen ◽  
Yun-Ting Chen ◽  
Ro-Ya Liu ◽  
Han-De Chen ◽  
Dengsung Lin ◽  
...  

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