Strain‑Induced Surface Interface Dual Polarization Constructs PML‑Cu/Bi_(12)O_(17)Br_(2) High‑Density Active Sites for CO_(2) Photoreduction

The insufficient active sites and slow interfacial charge trans-fer of photocatalysts restrict the efficiency of CO_(2) photoreduction.The synchronized modulation of the above key issues is demanding and chal-lenging.Herein,strain-induced strategy is developed to construct the Bi–O-bonded interface in Cu porphyrin-based monoatomic layer(PML-Cu)and Bi_(12)O_(17)Br_(2)(BOB),which triggers the surface interface dual polarization of PML-Cu/BOB(PBOB).In this multi-step polarization,the built-in electric field formed between the interfaces induces the electron transfer from con-duction band(CB)of BOB to CB of PML-Cu and suppresses its reverse migration.Moreover,the surface polarization of PML-Cu further promotes the electron converge in Cu atoms.The introduction of PML-Cu endows a high density of dispersed Cu active sites on the surface of PBOB,significantly promoting the adsorption and activation of CO_(2) and CO desorption.The conversion rate of CO_(2) photoreduction to CO for PBOB can reach 584.3μmol g-1,which is 7.83 times higher than BOB and 20.01 times than PML-Cu.This work offers valuable insights into multi-step polarization regulation and active site design for catalysts.

Cryo-induced closely bonded heterostructure for effective CO2 conversion:The case of ultrathin BP nanosheets/g-C3N4

Black phosphorus(BP),an interesting and multi-functional non-metal material,has attracted widespread attention.In this work,2D BP/2D g-C3N4 heterostructure had been fabricated at extremely low temperature,which was used to reduce CO2 for the first time.With introduction of 2D BP,the separation of photogenerated holes and electrons was extremely boosted,and composites showed excellent photocatalytic performance(CO2 to CO).Meanwhile,the targeted composite could keep high selectivity for CO generation and CO generation rate can be up to 187.7μmol g−1 h^−1.The formation process of the unique heterostructure and the key factor affecting the photocatalytic performance were also discussed.This work provides a new approach for designing metal free photocatalyst,which is used for CO2 reduction.

Multidimensional In_(2)O_(3)/In_(2)S_(3) heterojunction with lattice distortion for CO_(2) photoconversion

Photocatalytic CO_(2)reduction to sustainably product of fuels is a potential route to achieve clean energy conversion.Unfortunately,the sluggish charge transport dynamics and poor CO_(2)activation performance result in a low CO_(2)conversion efficiency.Herein,we develop a multidimensional In_(2)O_(3)/In_(2)S_(3)(IO/IS)heterojunction with abundant lattice distortion structure and high concentration of oxygen defects.The close contact interfaces between the junction of the two phases ensure undisturbed transmission of electrons with high‐speed.The increased free electron concentration promotes the adsorption and activation of CO2 on the catalyst surface,leaving the key intermediate*COOH at a lower energy barrier.The perfect combination of the band matching oxide and sulfide effectively reduces the internal energy barrier of the CO2 reduction reaction.Furthermore,the lattice distortion structure not only provides additional active sites,but also optimizes the kinetics of the reaction through microstructural regulation.Remarkably,the optimal IO/IS heterojunction exhibits superior CO_(2)reduction performance with CO evolution rate of 12.22μmol g^(−1)h^(−1),achieving about 4 times compared to that of In_(2)O_(3)and In2S3,respectively.This work emphasizes the importance of tight interfaces of heterojunction in improving the performance of CO_(2)photoreduction,and provides an effective strategy for construction of heterojunction photocatalysts.

Construction of 2D/2D Z-scheme MnO_(2-x)/g-C_(3)N_(4) photocatalyst for efficient nitrogen fixation to ammonia

Reducing nitrogen to ammonia with solar energy has become a wide concern when it comes to photocatalysis research.It is considered to be one of the more promising alternate options for the conventional Haber-Bosch cycle.Herein,2D g-C_(3)N_(4)composites with modifying ultrathin sheet MnO_(2-x)were prepared and used as nitrogen fixation photocatalyst.With the assistance of the nature of MnO_(2-x),the generation rate of NH_(3)reached 225 mmol g^(-1)h^(-1),which is more than twice over the rate of pristine 2D g-C_(3)N_(4)(107 mmol g^(-1)h^(-1)).The presence of ultrathin sheet MnO_(2-x)shortens the gap of the carriers to the surface of photocatalyst.Thus the speed of electron transfer gets increased.Besides,the construction of Z-scheme heterojunction boosts the separation and migration of photogenerated carriers.As a result,the nitrogen reduction reaction(NRR)performance gets enhanced.The work may provide an example of promoting the NRR performance of non-metallic compound.

Selective aerobic oxidation of p-cresol with co-catalysts between metalloporphyrins and metal salts

A green and efficient method for the selective aerobic oxidation of p-cresol to p-hydroxybenzaldehyde catalyzed by co-catalysts between metalloporphyrins and metal salts was investigated and developed. The relationship between the synergistic catalytic effects and the composition as well as amount of co-catalysts was investigated. Moreover, the influence of different reaction conditions was studied in details. A high p-cresol conversion （〉99%） and p-hydroxybenzaldehyde selectivity （83%） were obtained using only 1.125 × 10- 5 mol T（p-CH3O）PPFe111Cl-Co（OAc）2 used under mild, optimized reaction conditions. A possible mechanism for the reaction was also proposed. This work would be meaningful and instructive for the further researches and applications of co-catalyst system on oxidation of cresols and could give some enlightenment on the selectively catalytic oxidation of the side-chain alkyls of aromatics.

Unveiling the decomposition mechanism of formic acid on Pd/WC(0001) surface by using density function theory

In pursuit of low-cost direct formic acid fuel cells,tungsten carbide(WC)supported Pd catalyst is considered as an ideal candidate for efficient decomposition of formic acid due to low Pd utilization and excellent performance.Herein,different adsorption configurations and active sites of the intermediates,involved in the HCOOH decomposition,on WC(0001)-supported Pd monolayer(Pd/WC(0001))surface investigated by using density functional theory.The results reveal that trans-HCOOH,HCOO,cis-COOH,trans-COOH,HCO,CO,H2 O,OH and H exhibit chemisorption on Pd/WC(0001)surface,whereas cis-HCOOH and CO2 exhibit weak interactions with Pd/WC(0001)surface.In addition,the minimum energy pathways of HCOOH decomposition are analyzed to generate CO and CO2 due to the fracture of C–H,H–O and C–O bonds.The adsorbed HCOOH,HCOO,mH COO,cis-COOH and trans-COOH configurations exhibit dissociation rather than desorption.CO formation occurs through the decomposition of cis-COOH,trans-COOH and HCO,whereas the CO2 formation happens due to the decomposition of HCOO.It is found that the most favorable pathway for HCOOH decomposition on Pd/WC(0001)surface is HCOOH→HCOO→CO2,where the formation of CO2 from HCOO dehydrogenation determines the reaction rate.Overall,CO2 is the most dominant product of HCOOH decomposition on Pd/WC(0001)surface.The presence of WC,as monolayer Pd carrier,does not alter the catalytic behavior of Pd and significantly reduces the Pd utilization.

Catalyst-free and solvent-free oxidation of cycloalkanes(C5-C8) with molecular oxygen:Determination of autoxidation temperature and product distribution

Autoxidation of cycloalkanes （C5-C8） with molecular oxygen under catalyst-free and solvent-free conditions was conducted systematically for the first time, focusing on the autoxidation temperature and product distribution. The autoxidation of cyclopentane, cyclohexane, cycloheptane and cyclooctane occurs at 120 ℃, 130 ℃, 120 ℃, and 105 ℃ respectively, with obvious oxidized products formation. At 140 ℃, 145 ℃, 130 ℃ and 125 ℃, acceptable yields of the oxidized products could be obtained for them, and the oxidized product distributions were investigated in detail. The autoxidation of cycloalkanes follows the pseudo-first-order kinetic model and the apparent activation energies （Ea） for the autoxidation of cyclopentane and cyclohexane are 159.76 kJ. tool-1 and 86.75 kJ. mol-1 respectively. This study can act as an important reference in screen of suitable reaction temperature and comparison of the performance of various catalysts in the catalytic oxidation of cycloalkanes in the attempt to enhance the oxidized product selectivity.

A succinct enhanced luminescence strategy for fluorescent ionic liquids and the application for detecting CO_(2)

An interesting phenomenon was found that fluorophore was introduced into ionic liquid(IL)to magnify fluorescence signal via the thermally activated delayed fluorescence process;thus up to 15 fold enhancements were achieved.Hence,we reported a succinct enhanced luminescence strategy to reduce single-triplet energy split by the tunability of ILs.This strategy could be extended to more kinds of ILs by the virtue of a preliminary DFT calculation screening.Moreover,the optical feature of IL sensor made it a promising candidate as a gas fluorescence sensor.

Electrochemical C-H/N-H cross-coupling of 2-phenylindolizines with phenothiazines to synthesize novel N-aryl phenothiazine derivatives

A facile and elegant method for synthesis of novel N-aryl phenothiazine derivatives from 2-phenylindolizines and phenothiazines through direct electrochemical oxidation has been developed.This approach was performed smoothly at room temperature without external oxidant and catalyst.Cyclic voltammetry and in situ FTIR techniques were applied to analyze the cross-coupling process of phenothiazines and 2-phenylindolizines,which helped to select the appropriate reaction potential.Under the optimized conditions,a broad range of substrates were well tolerated,affording the desired products in moderate to excellent isolated yields(up to 91%)with high regioselectivity.Meanwhile,a plausible mechanism involving a radical pathway has been proposed.

氧气催化氧化环己烷

本文系统综述了O_2氧化剂用于环己烷催化氧化体系的研究进展,包括金属配合物催化、金属纳米粒子催化、金属氧化物粒子催化、分子筛催化、碳材料催化、光促进催化、杂多酸催化、金属-有机骨架材料催化等。本文认为研究、开发以O_2为氧化剂,高活性高选择性的非均相环己烷催化氧化体系将成为今后环己烷催化氧化研究的主要方向,尤其是多金属甚至多元素复合体系。本综述不仅对开发高催化活性高选择性的环己烷催化氧化体系,改进目前工业上的环己醇环己酮制备工艺具有重要的参考价值,而且还对其他烃类C—H键和C—C键高效催化氧化体系甚至其他氧化体系的研究与开发也具有重要的参考价值。

Advances and perspectives in catalysts for liquid-phase oxidation of cyclohexane

The latest progress and developments in catalysts for the oxidation of cyclohexane are reviewed. Catalytic systems for the oxidation of cyclohexane including metal supported, metal oxides, molecular sieves, metal substituted polyoxometalates, photocatalysts, orga nocatalysts, Gif systems, metal-organic catalysts and metalloporphyrins are discussed with a particular emphasis on metalloporphyrin catalytic systems. The advantages and disadvantages of these methods are summarized and analyzed. Finally, the development trends in the oxidation technology of cyclohexane are examined.

Mechanism of methanol decomposition on the Pd/WC(0001) surface unveiled by first-principles calculations

In this study,the decomposition of methanol into the CO and H species on the Pd/tungsten carbide(WC)(0001)surface is systematically investigated using periodic density functional theory(DFT)calculations.The possible reaction pathways and intermediates are determined.The results reveal that saturated molecules,i.e.,methanol and formaldehyde,adsorb weakly on the Pd/WC(0001)surface.Both CO and H prefer three-fold sites,with adsorption energies of-1.51 and-2.67 eV,respectively.On the other hand,CH30 stably binds at three-fold and bridge sites,with an adsorption energy of-2.58 eV.However,most of the other intermediates tend to adsorb to the surface with the carbon and oxygen atoms in their sp3 and hydroxyl-like configurations,respectively.Hence,the Catom of CH2OH preferentially attaches to the top sites,CHOH and CH2O adsorb at the bridge sites,while COH and CHO occupy the three-fold sites.The DFT calculations indicate that the rupture of the initial C-H bond promotes the decomposition of CH3OH and CH2OH,whereas in the case of CHOH,O-H bond scission is favored over the C-H bond rupture.Thus,the most probable methanol decomposition pathway on the Pd/WC(0001)surface is CH3OH→ CH2OH→trans-CUOH→CHO→CO.The present study demonstrates that the synergistic effect of WC(as carrier)and Pd(as catalyst)alters the CH3OH decomposition pathway and reduces the noble metal utilization.

Tuning the Excited State of Tetradentate Pd(ll) and Pt(ll) Complexes through Benzannulated N-Heteroaromatic Ring and Central Metal

A series of tetra de ntate Pd(ll)and Pt(ll)complexes containing fused 5/6/6 metallocycles with phe nyl/V-heteroaromatic ben-zo[d]imidazole(pbiz),benzo[d]oxazole(pboz)or benzo[d]thiazole(pbthz)-containing ligands was developed.Systematic studies by experiments and theoret:ical calculations reveal that both the central metal and the benzannulated A/-heteroaromatic ring have sig-n ificant in flue nee on the electrochemical,photophysical and excited-state properties of the Pd(ll)and Pt(ll)complexes.In identical condition,compared to pb/z-based Pd(ll)and Pt(ll)complexes,the corresponding metal complexes with pboz and pbthz-containing ligand show significant red-shift emission spectra.

Synthesis of p-substituted tetraphenylporphyrins and corresponding ferric complexes with mixed-solvents method

By using mixed-solvents method,five kinds of p-substituted tetraphenylporphyrin compounds[T(p-R)PPH_(2),R=NO_(2),Cl,CH_(3),OCH_(3),OH]were synthesized by the condensation of p-substituted benzaldehyde with pyrrole in mixed solvents(propionic acid,acetic acid and nitrobenzene),and corresponding ferric complexes[T(p-R)PPFe^(Ⅲ)Cl]were synthesized in dimethylformamide.The above free base porphyrins were obtained in 30%-50%yields,metalation yields were up to 90%and total yields of ferric complexes were 27%-50%.Effects of reactive conditions,solvents and oxidants on yields of free base porphyrins were investigated and the relevant mechanism was discussed.Structures of the above porphyrin complexes were characterized by ultravioletvisible(UV-Vis),infrared(IR)and far infrared(FIR)spectroscopy.

Selective epoxidation of linear terminal olefins with metalloporphyrins under mild conditions

The epoxidation of linear terminal olefins with metalloporphyrins in the presence of dioxygen and isobutyraldehyde under ambient temperature and atmo-spheric pressure was investigated.The results show that all olefins could be smoothly converted to epoxides with high selectivities(70%–90%).For the metalloporphyrins with different catalytic activities within 1-hexene epoxidation in the order of Fe>Mn>Co,T(o-Cl)PPFe(III)Cl was most effective,with a 41.7%yield and 80.2%selectivity of 1,2-epoxyhexane.Various amounts of catalyst were investi-gated,and it was found that with only 10ppm catalyst the yield of 1,2-epoxyhexane and turnover number(TON)could reach up to 41.9%and 41859,respectively.

Study on a green synthetic method of TRPPMCl(M=Fe,Mn,Co)

A green synthetic method using mixted solvents of di-methyl formamide(DMF)and acids instead of single DMF to synthesize metalloporphyrins(TRPPMCl)from TRPPH_(2) and MCl_(2) metallization was proposed in this paper.A series of TRPPMCl(M=Fe,Mn,Co)were synthesized through this innovative synthetic method,and these complexes were characterized with various spectroscopic techniques,includingIR and UV-Vis spectroscopy.The results showed that the metallization time was markedly reduced from about 10h to 0.5h in contrast with the conventional synthetic methods.

Selective oxidation of o-nitrotoluene to o-nitrobenzaldehyde with metalloporphyrins as biomimetic catalysts

Selective oxidation of o-nitrotoluene to onitrobenzaldehyde with metalloporphyrins as biomimetic catalysts was studied.The peripheral substituent around porphyrin rings and various process parameters of NaOH concentration,reaction temperature,reaction time and oxygen pressure all affect the selectivity of onitrobenzaldehyde.Further,82.0%selectivity of onitrobenzaldehyde was achieved under the optimum conditions:1.0×10^(-5)mol·L^(-1)of T(p-NO_(2))PPFeCl catalyst,2.5 mol·L^(-1)of NaOH,0.2 mol·L^(-1)of o-nitrotoluene,45℃and 2.0 MPa for 6 h.

Design, synthesis, and antiviral properties of 2-aryl-1H- benzimidazole-4-carboxamide derivatives

A series of new benzimidazole derivatives were designed and synthesized.Their chemical structures were testified by 1 H NMR,infrared spectroscopy(IR),mass spectrography(MS),and elemental analysis.Their potent antiviral properties indicated the prospect of new drugs.Compound 13,16,18,19,21,22,and 23 were identified as novel antivirus with much better selective activity and inhibitory activity than the comparable ribavirin against Coxsackie virus B_(3) in VERO cells.

Study on a green synthesis of μ-oxo-bis [tetraarylphenylporphyrinatoiron]

A novel method for the synthesis ofμ-oxo-bis[tetraarylporphyrinatoiron]([TRPPFe]_(2)O)based on the reaction between tetraarylporphyrinironchloride(TRPPFeCl)and H_(2)O in toluene was investigated in this paper.Three kinds of[TRPPFe]_(2)O were synthesized by this novel synthetic method,and their structures were characterized by elemental analysis,IR spectra and UV-Vis spectroscopy.