scholarly journals Static Regulation and Dynamic Evolution of Single‐Atom Catalysts in Thermal Catalytic Reactions

2018 ◽  
Vol 6 (3) ◽  
pp. 1801471 ◽  
Author(s):  
Hongliang Li ◽  
Menglin Wang ◽  
Laihao Luo ◽  
Jie Zeng
Keyword(s):  
Catalytic Reactions ◽  
Single Atom ◽  
Dynamic Evolution

Tunable Carbon Surface from Mono- to Multi-Metallic Single Atoms

2020 ◽  
Author(s):  
Weihong Lai ◽  
Heng Wang ◽  
Quan jiang ◽  
Zichao Yan ◽  
Hanwen Liu ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Structural Evolution ◽  
Charge Compensation ◽  
Catalytic Reactions ◽  
Single Atom ◽  
Carbon Surface ◽  
Hydrogen Electrode ◽  
Single Atoms ◽  
Mass Activity ◽  
Co Doped

<p>Herein, we develop a non-selective charge compensation strategy to prepare multi-single-atom doped carbon (MSAC) in which a sodium p-toluenesulfonate (PTS-Na) doped polypyrrole (S-PPy) polymer is designed to anchor discretionary mixtures of multiple metal cations, including iron (Fe<sup>3+</sup>), cobalt (Co<sup>3+</sup>), ruthenium (Ru<sup>3+</sup>), palladium (Pd<sup>2+</sup>), indium (In<sup>3+</sup>), iridium (Ir<sup>2+</sup>), and platinum (Pt<sup>2+</sup>) . As illustrated in Figure 1, the carbon surface can be tuned with different level of compositional complexities, including unary Pt<sub>1</sub>@NC, binary (MSAC-2, (PtFe)<sub>1</sub>@NC), ternary (MSAC-3, (PtFeIr)<sub>1</sub>@NC), quaternary (MSAC-4, (PtFeIrRu)<sub>1</sub>@NC), quinary (MSAC-5, (PtFeIrRuCo)<sub>1</sub>@NC), senary (MSAC-6, (PtFeIrRuCoPd)<sub>1</sub>@NC), and septenary (MSAC-7, (PtFeIrRuCoPdIn)<sub>1</sub>@NC) samples. The structural evolution of carbon surface dictates the activities of both ORR and HER. The senary MSAC-6 achieves the ORR mass activity of 18.1 A·mg<sub>metal</sub><sup>-1</sup> at 0.9 V (Vs reversible hydrogen electrode (RHE)) over 30K cycles, which is 164 times higher than that of commercial Pt/C. The quaternary MSAC-4 presented a comparable HER catalytic capability with that of Pt/C. These results indicate that the highly complexed carbon surface can enhance its ability over general electrochemical catalytic reactions. The mechanisms regarding of the ORR and HER activities of the alternated carbon surface are also theoretically and experimentally investigated in this work, showing that the synergistic effects amongst the co-doped atoms can activate or inactivate certain single-atom sites.</p>

Active site engineering of atomically dispersed transition metal-heteroatom-carbon catalysts for oxygen reduction

2021 ◽  
Author(s):  
Jiawei Zhu ◽  
Shichun Mu
Keyword(s):  
Transition Metal ◽  
Oxygen Reduction ◽  
Active Site ◽  
Catalytic Reactions ◽  
Single Atom ◽  
Carbon Catalysts

Owing to the advantage of atomic utilization, the single-atom catalyst has attracted much attention and been employed in multifarious catalytic reactions. Their definite site configuration is favorable for exploring the...

Zero-Valent Pd Atoms Anchored on Polyoxometalate for Low Temperature Hydrodeoxygenation

2020 ◽  
Author(s):  
Max J. Huelsey ◽  
Geng Sun ◽  
Bin Zhang ◽  
Yao Xu ◽  
Shipeng Ding ◽  
...  
Keyword(s):  
Low Temperature ◽  
Reaction Rates ◽  
Catalytic Reactions ◽  
Oxidation States ◽  
Single Atom ◽  
Oxide Supports ◽  
Renewable Fuel ◽  
Bond Hydrogenation ◽  
Shed Light ◽  
Positively Charged

Single-atom catalysts usually comprise positively charged atomically dispersed metal cations on oxide supports. Neutral atoms on oxides are synthetically challenging, and their performance in catalytic reactions remains ambiguous. Here, we shed light on this question with the design of Pd single-atom catalysts on polyoxometalates. Depending on the composition of the support, Pd can either exhibit oxidation states of 0 or 2+. We show that this difference is decisive for the C-O bond hydrogenolysis while displaying negligible effects on the C=O bond hydrogenation. The selective conversion of 5-hydroxymethylfurfural (5-HMF) to 2,5-dimethylfuran (2,5-DMF), a key renewable fuel compound, was shown to occur at 253 K with reaction rates up to 71.0 per hour.<br>

Dynamic evolution of specific catalytic sites on Pt nanoparticles

2016 ◽  
Vol 6 (1) ◽  
pp. 144-151 ◽  
Author(s):  
Hector Barron ◽  
George Opletal ◽  
Richard D. Tilley ◽  
Amanda S. Barnard
Keyword(s):  
Surface Defects ◽  
Pt Nanoparticles ◽  
Catalytic Reactions ◽  
Dynamic Evolution ◽  
Stages Of Growth ◽  
Early Stages ◽  
Catalytic Sites ◽  
Different Types

Different types of surface defects are needed for specific types of catalytic reactions, and can be promoted or suppressed by varying the temperature and rates during the early stages of growth.

scholarly journals Catalytically potent and selective clusterzymes for modulation of neuroinflammation through single-atom substitutions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haile Liu ◽  
Yonghui Li ◽  
Si Sun ◽  
Qi Xin ◽  
Shuhu Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Reactions ◽  
Single Atom ◽  
Artificial Enzymes ◽  
Signal Molecules ◽  
High Catalytic Activity ◽  
Substrate Selectivity ◽  
Catalytic Activities ◽  
Injured Brain ◽  
Enzyme Mimicking

AbstractEmerging artificial enzymes with reprogrammed and augmented catalytic activity and substrate selectivity have long been pursued with sustained efforts. The majority of current candidates have rather poor catalytic activity compared with natural molecules. To tackle this limitation, we design artificial enzymes based on a structurally well-defined Au25 cluster, namely clusterzymes, which are endowed with intrinsic high catalytic activity and selectivity driven by single-atom substitutions with modulated bond lengths. Au24Cu1 and Au24Cd1 clusterzymes exhibit 137 and 160 times higher antioxidant capacities than natural trolox, respectively. Meanwhile, the clusterzymes demonstrate preferential enzyme-mimicking catalytic activities, with Au25, Au24Cu1 and Au24Cd1 displaying compelling selectivity in glutathione peroxidase-like (GPx-like), catalase-like (CAT-like) and superoxide dismutase-like (SOD-like) activities, respectively. Au24Cu1 decreases peroxide in injured brain via catalytic reactions, while Au24Cd1 preferentially uses superoxide and nitrogenous signal molecules as substrates, and significantly decreases inflammation factors, indicative of an important role in mitigating neuroinflammation.

Pt1-O4 as active sites boosting CO oxidation via a non-classical MvK mechanism

2021 ◽  
Author(s):  
Yang Lou ◽  
Yongping Zheng ◽  
Wenyi Guo ◽  
Jingyue Liu
Keyword(s):  
Co Oxidation ◽  
Active Sites ◽  
Total Activity ◽  
Catalytic Reactions ◽  
Single Atom ◽  
Excellent Performance ◽  
Practical Applications ◽  
Square Planar

Single-atom catalysts (SACs) possess excellent performance for various catalytic reactions but it is still challenging to have adequate total activity for practical applications. Here we report the high-valence, square planar...

scholarly journals Tunable Carbon Surface from Mono- to Multi-Metallic Single Atoms

2020 ◽  
Author(s):  
Weihong Lai ◽  
Heng Wang ◽  
Quan jiang ◽  
Zichao Yan ◽  
Hanwen Liu ◽  
...  
Keyword(s):  
Synergistic Effects ◽  
Structural Evolution ◽  
Charge Compensation ◽  
Catalytic Reactions ◽  
Single Atom ◽  
Carbon Surface ◽  
Hydrogen Electrode ◽  
Single Atoms ◽  
Mass Activity ◽  
Co Doped

<p>Herein, we develop a non-selective charge compensation strategy to prepare multi-single-atom doped carbon (MSAC) in which a sodium p-toluenesulfonate (PTS-Na) doped polypyrrole (S-PPy) polymer is designed to anchor discretionary mixtures of multiple metal cations, including iron (Fe<sup>3+</sup>), cobalt (Co<sup>3+</sup>), ruthenium (Ru<sup>3+</sup>), palladium (Pd<sup>2+</sup>), indium (In<sup>3+</sup>), iridium (Ir<sup>2+</sup>), and platinum (Pt<sup>2+</sup>) . As illustrated in Figure 1, the carbon surface can be tuned with different level of compositional complexities, including unary Pt<sub>1</sub>@NC, binary (MSAC-2, (PtFe)<sub>1</sub>@NC), ternary (MSAC-3, (PtFeIr)<sub>1</sub>@NC), quaternary (MSAC-4, (PtFeIrRu)<sub>1</sub>@NC), quinary (MSAC-5, (PtFeIrRuCo)<sub>1</sub>@NC), senary (MSAC-6, (PtFeIrRuCoPd)<sub>1</sub>@NC), and septenary (MSAC-7, (PtFeIrRuCoPdIn)<sub>1</sub>@NC) samples. The structural evolution of carbon surface dictates the activities of both ORR and HER. The senary MSAC-6 achieves the ORR mass activity of 18.1 A·mg<sub>metal</sub><sup>-1</sup> at 0.9 V (Vs reversible hydrogen electrode (RHE)) over 30K cycles, which is 164 times higher than that of commercial Pt/C. The quaternary MSAC-4 presented a comparable HER catalytic capability with that of Pt/C. These results indicate that the highly complexed carbon surface can enhance its ability over general electrochemical catalytic reactions. The mechanisms regarding of the ORR and HER activities of the alternated carbon surface are also theoretically and experimentally investigated in this work, showing that the synergistic effects amongst the co-doped atoms can activate or inactivate certain single-atom sites.</p>

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