Ultra-long room temperature phosphorescence of indium-based organic inorganic metal halides for naked-eye-visible afterglow

Solid-state molecules based on room-temperature phosphorescent(RTP)emission have received extensive attention due to their special optical properties of triplet excitons.However,there are still few solid molecular systems with naked-eye-visible afterglow characteristics.Herein,we introduce 4-phenylbenzylamine(namely PBA)with a long conjugated system into common non-toxic In^(3+)to form an indium-based organic inorganic halide,whose chemical formula is PBA_(3)[InCl_6]·H_(2)O.Interestingly,this hybrid halide generates a RTP emission at 617 nm with a lifetime decay as long as 290.4 ms,expressing a naked-eye-visible afterglow for more than 7 s.The mechanism study shows that the long lifetime RTP originated from the specific lamellar stacking of organic molecules and metal halide units,facilitating the interaction between the inorganic layers and organic layers.Therefore,the material can be potentially used in emergency lighting,information security,and other fields.Meanwhile,this work provides a reference for the design and implementation of a more efficient organic-inorganic hybrid system with the ultralong RTP emission.

Rational design of graphyne-based dual-atom site catalysts for CO oxidation

There are increasing concerns about the environmental impact of rising atmospheric carbon monoxide concentrations,thus it is necessary to develop new catalysts for efficient CO oxidation.Based on first-principles calculations,the potential ofγ-graphyne(GY)as substrate for metals in the 4th and 5th periods under single-atom and dual-atoms concentration modes has been systematically investigated.It was found that single-atom Co,Ir,Rh,and Ru could effectively oxidate CO molecules,especially for single Rh.Furthermore,proper atoms concentration could boost the CO oxidation activity by supplying more reaction centers,such as Rh^(2)/GY.It was determined that two Rh atoms in Rh^(2)/GY act different roles in the catalytic reaction:one structural and another functional.Screening tests suggest that substituting the structural Rh atom in the center of acetylenic ring by Co or Cu atom is a possible way to maintain the reaction performance while reducing the noble metal cost.This systemic investigation will help in understanding the fundamental reaction mechanisms on GY-based substrates.We emphasize that properly exposed frontier orbital of functional metal atom is crucial in adsorption configuration as well as entire catalytic performance.This study constructs a workflow and provides valuable information for rational design of CO oxidation catalysts.

Cobalt single atom site catalysts with ultrahigh metal loading for enhanced aerobic oxidation of ethylbenzene

The oxidation of hydrocarbons to produce high value-added compounds(ketones or alcohols)using oxygen in air as the only oxidant is an efficient synthetic strategy from both environmental and economic views.Herein,we successfully synthesized cobalt single atom site catalysts(Co SACs)with high metal loading of 23.58 wt.%supported on carbon nitride(CN),which showed excellent catalytic properties for oxidation of ethylbenzene in air.Moreover,Co SACs show a much higher turn-over frequency(19.6 h^(−1))than other reported non-noble catalysts under the same condition.Comparatively,the as-obtained nanosized or homogenous Co catalysts are inert to this reaction.Co SACs also exhibit high selectivity(97%)and stability(unchanged after five runs)in this reaction.DFT calculations reveal that Co SACs show a low energy barrier in the first elementary step and a high resistance to water,which result in the robust catalytic performance for this reaction.

Cobalt diselenide (001) surface with short-range Co-Co interaction triggering high-performance electrocatalytic oxygen evolution

Oxygen evolution reaction (OER) still suffers from the bottleneck in electrocatalytic water splitting. Herein, in virtue of volcano plots drawn by theoretical calculation, the (001) facet was screened as the superb facet of orthorhombic CoSe_(2) for OER. Afterwards, CoSe_(2)(001) nanosheets were synthesized and the exposure ratio of (001) facet is controllable with thermodynamics methods effectively. The single-facet CoSe2(001) delivered an overpotential as low as 240 mV at 10 mA·cm^(−2) in 1 M KOH, which outperformed the bulk (380 mV) as well as other CoSe_(2)-base OER catalysts reported before. Especially, a shorter Co-Co path was observed in CoSe_(2)(001) by X-ray absorption spectroscopy. Further density functional theory (DFT) studies revealed that the reversible compression on the shorter Co-Co path could regulate the electronic structure of active sites during the OER process, and thus the energy barrier of the rate-determining step was reduced by 0.15 eV. This work could inspire more insights on the modification of electronic structure for OER electrocatalysts.

Interplay between invasive single atom Pt and native oxygen vacancy in rutile TiO_(2)(110)surface:A theoretical study

Oxygen vacancy(O_(v))as well as Ov migration in metal oxide are of great importance in structural evolution of active center in single-atom catalysts(SACs).Here,the interplay between invasive single Pt atom and native O_(v) in SA-Pt/rutile TiO_(2)(110)surface,as well as their synergetic effect on water dissociation are investigated by density functional theory(DFT)calculations.We show that importing Pt atom as Pt-ads,Pt_(2c),Pt_(5c) and Pt6c modes could decelerate the O_(v) migration effectively,especially in Pt6c mode.Under oxygen-rich conditions,Pt6c substitution could make oxygen Ov formation easier,but migration harder.On Pt_(6c)/Ti_(1-y)O_(2-x1)(110)surface,as a bimetal center,Pt_(4c)-Ti_(5c) concave could not make water dissociation process easier;however,the O2c closed to Pt become a good proton acceptor to make water dissociation on Ti_(5c)-O_(2c) more convenient with the aid of topmost Ti_(5c).