Single-atom catalysts offer maximal atom utilization efficiencies and high-electronegativity heteroatoms play a crucial role in coordinating reactive single metal atoms to prevent agglomeration. However, these strong coordination bonds withdraw electron density for coordinated metal atoms and consequently affect their catalytic activity. Herein we reveal the high loading (11.3 wt%) and stabilization of moderately coordinated Cu-P3 structure on black phosphorus support by a photochemical strategy with auxiliary hydrogen. Single-atom Cu sites with an exceptional electron-rich feature show the $$\triangle {G}_{{{{{{\rm{H}}}}}}*}$$
△
G
H
*
close to zero to favor catalysis. Neighboring Cu atoms work in synergy to lower the energy of key water adsorption and dissociation intermediates. The reported catalyst shows a low overpotential of only 41 mV at 10 mA cm−2 and Tafel slope of 53.4 mV dec−1 for the alkaline hydrogen evolution reaction, surpassing both isolated Cu single atoms and Cu nanoclusters. The promising materials design strategy sheds light on the design and fabrication of high-loading single metal atoms and the role of neighboring single atoms for enhanced reaction kinetics.
Encapsulation engineering is an effective strategy to improve the stability of perovskite solar cells. However, current encapsulation materials are not suitable for lead-based devices because of their complex encapsulation processes, poor thermal management, and inefficient lead leakage suppression. In this work, we design a self-crosslinked fluorosilicone polymer gel, achieving nondestructive encapsulation at room temperature. Moreover, the proposed encapsulation strategy effectively promotes heat transfer and mitigates the potential impact of heat accumulation. As a result, the encapsulated devices maintain 98% of the normalized power conversion efficiency after 1000 h in the damp heat test and retain 95% of the normalized efficiency after 220 cycles in the thermal cycling test, satisfying the requirements of the International Electrotechnical Commission 61215 standard. The encapsulated devices also exhibit excellent lead leakage inhibition rates, 99% in the rain test and 98% in the immersion test, owing to excellent glass protection and strong coordination interaction. Our strategy provides a universal and integrated solution for achieving efficient, stable, and sustainable perovskite photovoltaics.
A novel palladium-catalyzed spirocyclization through sequential Narasaka-Heck, C-H activation and [4+2] annulation has been developed. In this reaction, cheap and readily available 2-chlorobenzoic acid or ethyl phenylpropiolate was employed as...
A helically twisted ribbon-shaped nanographene 3 containing four pentagons, eighteen hexagons and four heptagons was synthesized by a cascade of classical Scholl and non-classical Scholl-type cycloheptatriene formation reactions. In the...
A visible-light-promoted cyclization and aromatization of chalcones with 2-mercaptobenzimidazoles has been successfully developed to obtain diverse imidazo[2,1-b]thiazoles, and the C-S and C-N bonds were constructed in one step. The reaction...
For the upsurge of high breakdown strength ($${{{{{{\rm{E}}}}}}}_{{{{{{\rm{b}}}}}}}$$
E
b
), efficiency ($${{{{{\rm{\eta }}}}}}$$
η
), and discharge energy density ($${{{{{{\rm{U}}}}}}}_{{{{{{\rm{e}}}}}}}$$
U
e
) of next-generation dielectrics, nanocomposites are the most promising candidates. However, the skillful regulation and application of nano-dielectrics have not been realized so far, because the mechanism of enhanced properties is still not explicitly apprehended. Here, we show that the electric field cavity array in the outer interface of nanosieve-substrate could modulate the potential distribution array and promote the flow of free charges to the hole, which works together with the intrinsic defect traps of active Co3O4 surface to trap and absorb high-energy carriers. The electric field and potential array could be regulated by the size and distribution of mesoporous in 2-dimensional nano-sieves. The poly(vinylidene fluoride-co-hexafluoropropylene)-based nanocomposites film exhibits an $${{{{{{\rm{E}}}}}}}_{{{{{{\rm{b}}}}}}}$$
E
b
of 803 MV m−1 with up to 80% enhancement, accompanied by high $${{{{{{\rm{U}}}}}}}_{{{{{{\rm{e}}}}}}}$$
U
e
= 41.6 J cm−3 and $${{{{{\rm{\eta }}}}}}\,$$
η
≈ 90%, outperforming the state-of-art nano-dielectrics. These findings enable deeper construction of nano-dielectrics and provide a different way to illustrate the intricate modification mechanism from macro to micro.
The barriers for elementary steps in the oxygen reduction reaction (ORR) catalyzed on Au(100) in alkaline solution are mapped out by ab initio molecular dynamics simulations. Due to the relatively weak binding energy of O2 and oxygenated species, the calculated O−O dissociation barrier at ~0.5 eV is indeed considerably higher than the association barrier (< 0.1 eV) to form adsorbed HOO*, pushing ORR towards the thermodynamically less favorable 2e− pathway. However, the kinetics is changed above the equilibrium potential for the association channel ~0.7 V (RHE) where the 2e− pathway is switched off. Thereafter, the 4e− pathway becomes active as the O−O dissociation barrier at ~0.5 eV is not prohibitive. For the subsequent reduction steps, the weak binding energies of oxygenated species on Au(100) are actually an advantage, making Au(100) as good an ORR catalyst as Pt. It also makes the outer sphere electron transfer to O2 as the eventual rate determining step, as supported by the j-E polarization curve, showing a small ORR current extending close to the overall 4e− ORR equilibrium potential of 1.23 V. It provides an example on how the ORR activity volcano curve based on the Sabatier Principle can be circumvented in electrocatalysis.
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