CO Groups Research Articles

Sulfur-decorated Fe/C composite synthesized from MIL-88A(Fe) for peroxymonosulfate activation towards tetracycline degradation: Multiple active sites and non-radical pathway dominated mechanism

Peroxymonosulfate (PMS)-mediated advanced oxidation processes gain growing attention in degrading antibiotics (e.g., tetracycline (TC)) in wastewater for their high capacity and relatively low cost, while designing efficient catalysts for PMS activation remains a challenge. In this study, a sulfur-doped Fe/C catalyst (Fe@C–S) synthesized from iron metal-organic frameworks (Fe-MOFs) was developed for PMS activation towards TC removal. Under optimal conditions, the TC removal efficiency of Fe@C–S150/PMS system within 40 min was 91.2%. Meanwhile, the k value for Fe@C–S150/PMS system (0.2038 min−1) was 3.36-fold as high as the S-free Fe@C-based PMS system. Also, Fe@C–S150/PMS system showed high robustness in different water matrices. Further studies found that the TC degradation mechanism was mainly ascribed to the non-radical pathway (1O2 and electron transfer). Fe nanoparticles, S and CO groups on the catalyst all participated in the generation of reactive oxygen species (ROS). Besides, S species could enhance the Fe2+/Fe3+ redox cycle and accelerate the electron transfer process. This work highlights the critical role of S in enhancing the catalytic performance of Fe/C-based catalysts for PMS activation, which would provide meaningful insights into the design of high-performance PMS activators for the sustainable remediation of emerging contaminants-polluted water bodies.

A biochar-based catalyst prepared by potassium ferrate oxidation coupled high-temperature pyrolysis and its application for the activation of peroxymonosulfate towards the degradation of norfloxacin: Performance and mechanism insight

Developing an efficient catalyst for persulfate activation is critical to the high-efficiency degradation of organic pollutants in an aqueous solution using a persulfate-based advanced oxidation method. A biochar-based catalyst, 800Fe2BC2, was prepared using a novel technology of potassium ferrate oxidation coupled with high-temperature pyrolysis based on the biomass raw material of waste branches pruned from apple trees in an orchard. Batch tests were conducted to degrade norfloxacin using 800Fe2BC2 to activate peroxymonosulfate (PMS). Norfloxacin was almost completely degraded within 10 min. The reactive oxygen species (ROS), for instance, •OH, SO4•−, O2•−and 1O2, were generated in the 800Fe2BC2/PMS system. The iron oxides, defective structures, and CO groups in 800Fe2BC2 served as catalytic sites for generating free radicals. However, the recombination of superoxide radicals, the interaction of CO groups on the catalyst surface with PMS, and the self-decomposition of PMS contributed to generating 1O2. The quenching test showed that the degree of the contribution of •OH, SO4•−, O2•−and 1O2 to NOR degradation was approximately 1O2 > O2•− > SO4•− > •OH, respectively. We proposed three potential NOR degradation pathways: piperazine ring opening (P), quinolone ring oxidation (Q), and benzene ring defluorination (F). Then part of these intermediates was completely mineralized into inorganics like CO2, H2O, NO3− and F−. The acute and chronic toxicity of the degradation products were estimated, and the evolution of toxicity in the present catalytic system could not be ignored and should be overcome by deeper mineralization. The prepared 800Fe2BC2 demonstrated a good application prospect with good stability, recyclability, low metal leaching, and versatility to various refractory pollutants. Therefore, this study offered a new way of producing biochar-based catalysts for activating PMS using biomass wastes.

Insight into etherification of 1,3-dimethylol-2-imidazolidinone with the primary alcohols and the hydroxyl groups of cellulose chain (n = 1–4) in acidic condition

Etherification of 1,3-dimethylol-2-imidazolidinone (DMEU) with the primary alcohols and the hydroxyl groups of cellulose chain (n = 1–4) in acidic condition were probed in both gas phase and water solvent by using the Onsager model and polarized continuum model (PCM). Geometry and energy of reactants, products, intermediate complexes, carbocation intermediate, and transition state (TS) structures were calculated by using the methods of MP2, B3LYP, PM3MM at the basis sets of 6-311+g (d), 6-311g (d,p). The computational results indicate that the etherification adheres to unimolecular nucleophilic substitution (SN1) mechanism; reactants and products can form the activated complexes with H+ ions in which H+ ions are occupied by the O-atom of CO group in the reactant complex and the product complex. Potential energy surface (PES) of the reaction has the triple-well shape. Effect of substituent R in primary alcohol R-CH2OH (R = H, CH3, CH2CH3, CH2OCH3, CH2F) on the reactivity is significant. The energy barrier of H+ ions releasing step is much higher than those of the activation steps. The calculational data is in the good agreement with the experimental data in the literature.

Biomass derived fibrous porous carbon loaded zinc oxide nanoparticles as high-performance anode materials for lithium ion batteries

The use of absorbent cotton as a biomass-derived carbon skeleton has been rarely reported. In this study, zinc oxide (ZnO) was loaded on the surface of a fibrous structure derived from absorbent cotton porous carbon (PC), thereby improving its electrochemical and rate performances. The reversible capacity of the as-fabricated ZnO@PC composite, used as anode material, reached 611.0 mAh g−1 after 200 charge–discharge cycles, and its full-battery electrochemical performance was excellent. After 880 cycles, the full-battery capacity retention rate reached 74.85 %. The improvement in the electrochemical performance of the ZnO@PC composite is attributed to (1) the introduction of N-doped carbon skeletons into the composite to improve its electrical conductivity, (2) promoting effect of the fibrous structure on the electrochemical stability of the composite, the CO group was introduced into the system during the acetylation of cellulose with CH3COO−, which gives the composite higher binding energy with Li+ increases the full battery long cycle life, and (3) increase in the number of electrochemically active sites due to the large specific surface area of the composite. The as-fabricated composite can be used in high-performance lithium-ion batteries.

Nitrogen-doped carbon dots for doxorubicin-targeted delivery and two-photon cell imaging

Nitrogen (N) doped CDs (N-CDs) were prepared using citric acid and hexamethylenetetramine by a one-step hydrothermal method, characterized by transmission electron microscopy (TEM), Powder X-ray Diffractometer (PXRD), Nuclear Magnetic Resonance (13C NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), and ultraviolet–visible (UV–vis) absorption spectra. The doping mechanism and drug-loading characteristics of N-CDs were also studied. The results showed that N-CDs had both down- and up-conversion fluorescence properties and the average particle size was about 4.28 nm. N-CDs could be used as a drug carrier for doxorubicin (DOX) (N-CDs-DOX) via the formation of the NC bond, and the drug-loading rate of N-CDs-DOX was 35.88%. The N-CDs-DOX had pH-targeted properties and low cytotoxicity. In vitro release of N-CDs-DOX belonged to the Weibull model and Fick diffusion. The results showed that N-CDs could deliver DOX successfully, and collocate with DOX in the SH-SY5Y cells through two-photon imaging. The N-CDs-DOX system had sustained-release and pH-targeted properties. N-CDs were expected to deliver a type of drugs containing CO group and be used in cancer treatment.

The role of primary amines in modified chitosan to enhance the aldol condensation of biomass-derived carbonyl compounds

Aldol condensation is a key step for converting the lignocellulosic platform compounds to fuel. The catalyst used in the aldol condensation requires the avoidance of the overactivation of aldehyde groups while fully activating ketone carbonyl groups. Herein, the modified chitosan (NaOH/CT-0.6) was applied for the efficient syntheses of single condensation product from biomass-derived furfural (FFR) and methyl isobutyl ketone (MIBK), achieving an 87.01% yield of C11 at 60 °C and 3 h. Catalyst characterization revealed that the exposure of –NH2 groups in chitosan after modification led to the formation of the imine with the CO groups of FFR. It was confirmed that the imine formation avoided the overactivation of aldehyde groups and improved cross-condensation product yield. Furthermore, the theoretical feasibility of the imine catalytic path was elucidated through DFT simulation and in situ DRIFTS analysis. Finally, the obtained condensation products were subjected to hydrodeoxygenation (HDO) over the 2 wt% Pd/Nb2O5, obtaining the hydrocarbon components suitable for bio-jet fuels. This work contributes significantly to the design of novel catalysts for aldol condensation reactions and the efficient conversion of biomass.

Study on recovery of residual carbon from coal gasification fine slag and the influence of oxidation on its characteristics

Coal gasification fine slag (CGFS) is a kind of solid waste that is difficult to separate and utilize. In this work, ultrasonic-assisted flotation was used to recover residual carbon (RC) from CGFS. The ultrasonic treatment not only promotes the separation of RC and ash, but also improves the surface hydrophobicity of CGFS. Compared with conventional flotation, the loss on ignition (LOI) of concentrates and flotation perfect index obtained by ultrasonic-assisted flotation were increased by 12.21% and 4.57%, respectively. In addition, the RC was modified by air and steam. The characterization results of the samples show that air oxidation can significantly improve the oxygen-containing groups on the RC surface, especially the CO groups, and steam treatment is more conducive to increase the disorder of carbon microstructure. Furthermore, the textural properties of the RC were developed by air-steam treatment, and the highest specific surface area and pore volume of the oxidized RC were increased by 27.25 times and 6 times than the raw RC, respectively. RC-A2S2 obtained by air-steam alternating treatment had a high CO2 storage capacity of 2.00 mmol/g at 25 °C. The above research results have important reference value for strengthening of CGFS flotation and utilization of RC.

Efficient cavity-enhanced adsorption and recovery of low-concentration ammonia on pillar[5]arenes

Ammonia (NH3) capture has great implications for environmental protection and resource recovery. Developing effective and recyclable adsorbent materials to remove low-concentration NH3 in industrial waste gas is critical. Here, solid adsorbents per-hydroxylated pillar[5]arene (OHP[5]) and pillar[5]quinone (P[5]Q) with well-designed functional groups were synthesized and evaluated for NH3 adsorption. The results showed that both materials have high NH3 uptake capacity and excellent cycle stability. P[5]Q showed higher NH3 capacity (15.4 mmol/g) than OHP[5] (11.5 mmol/g) at ambient conditions (293.2 K and 1.0 bar). Dynamic breakthrough experiments showed that P[5]Q had good separation performance on low concentration NH3. Characterizations (including FTIR, SEM, and XPS) and density functional theory (DFT) studies revealed that the adsorption strength for NH3 on P[5]Q possessing CO groups was stronger than OHP[5] composed of phenolic hydroxyls. Also, the electron-accepting CO groups on P[5]Q could change the intramolecular charge distribution, in which an amount of NH3 enters and stores in the electron-deficient internal cavity of P[5]Q. It is demonstrated that P[5]Q with the suitable cavity has good potential for separating low concentration NH3 from industrial waste gas.

Sports Participation Promotes Beneficial Adaptations in the Erythrocyte Guanylate Nucleotide Pool in Male Athletes Aged 20-90 Years.

The guanine nucleotide pool (GTP, guanosine-5'-triphosphate; GDP, guanosine-5'-diphosphate, and GMP, guanosine-5'-monophosphate) is an essential energy donor in various biological processes (eg protein synthesis and gluconeogenesis) and secures several vital regulatory functions in the human body. The study aimed to predict the trends of age-related changes in erythrocyte guanine nucleotides and examine whether competitive sport and related physical training promote beneficial adaptations in erythrocyte guanylate concentrations. The study included 86 elite endurance runners (EN) aged 20-81 years, 58 sprint-trained athletes (SP) aged 21-90 years, and 62 untrained individuals (CO) aged 20-68 years. The concentration of erythrocyte GTP and total guanine nucleotides (TGN) were highest in the SP group, lower in the EN group, and lowest in the CO group. Both athletic groups had higher guanylate energy charge (GEC) values than the CO group (p = 0.012). Concentrations of GTP, TGN, and GEC value significantly decreased, while GDP and GMP concentrations progressively increased with age. Such a profile of change suggests a deterioration of the GTP-related regulatory function in older individuals. Our study explicitly shows that lifelong sports participation, especially of sprint-oriented nature, allows for maintaining a higher erythrocyte guanylate pool concentration, supporting cells' energy metabolism, regulatory and transcription properties, and thus more efficient overall body functioning.

Antibacterial and antioxidant activities of curcumin/Zn metal complex with its chemical characterization and spectroscopic studies

Curcumin is an active component of the rhizome turmeric. Curcumin/zinc (Cur/Zn) complex was synthesized and characterized using the elemental analysis, the molar conductance, FT-IR, UV–Vis,1HNMR, scanning (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The molar conductance value is very low, referring to the absence of Cl− ions inside or outside chelate sphere confirming non electrolytic nature. Based on IR and electronic spectra curcumin CO group in enol form chelated to Zn (II) ion. The surface morphology of curcumin chelate with Zn showed elevated in particle size and irregular grains shaped with elongated morphology. Transmission electron microscopy revealed that the curcumin chelate with Zn has spherical black spots like shape with particle size range from (33–97 nm). The antioxidant activities of curcumin and Cur/Zn complex were assessed. Results showed that the Cur/Zn complex showed potent antioxidant activities than curcumin. For antibacterial activity, Curcumin/Zn showed inhibitory effect against both (+ve and –ve) gram bacteria (Bacillus subtilis and Escherichia coli) at very low concentration. Cur/Zn recorded antibacterial and inhibition activity at 0.009 against E. coli and at 0.625 against B. subtilis. Cur/Zn complex showed higher capacity in scavenging the ABTS radical, FARAP capacity and metal chelating activity than curcumin itself and it showed more scavenging and inhibition activity for DPPH. The synthesized complex of Cur/Zn showed potent antioxidant and antibacterial activities than curcumin itself and it may benefit in treatment of aging and degenerative diseases with elevated and excessive production of free radicals.

Effects of fuel-staged gasification on mechanism of steam gasification of coal gangue and corn straw

Coal gangue (CG) and corn straw (CS) are regarded as the bulk of solid wastes in China due to their high annual yield, inefficient utilization, and low added value. In this work, the comparison experiments between fuel-staged gasification and conventional co-gasification for CG and CS were conducted in a new type of three-way reactor. The effects of volatiles and AAEMs in CS on fuel-staged gasification were analyzed by investigating CS ratio in the primary bed. And the influence of diffusion resistance was studied by adjusting CG ratio in the secondary bed. The results showed that the thermal interactions of CG and CS in primary bed were considered as the oxidation of C–C and CC structures of CG by C–O–C and C–OH bonds of CS to form CO. Meanwhile, the breaking of O–CO and lactone groups could generate a significant amount of CO2 to accelerate the Boudouard reaction of primary char. In addition, calcium minerals in CS could combine with CG minerals into anorthite, which would promote the transverse fracture and longitudinal stacking of primary residue char. Besides, steam reforming of volatiles/tar and ring-opening reactions of residue char were both controlled by the diffusion resistance derived from secondary CG. The conclusions would provide some theoretical bases and engineering foundations for the industrial applications of fuel-staged gasification, such as the design of fuel-staged gasifier and the selection of two-staged fuel.

EXTRACTION EXTRACTION AND CHARACTERIZATION OF PECTIN FROM LEMON LIME PEEL WASTE (Citrus amblycarpa)

Research on the extraction and characterization of pectin from lemon lime peel waste (Citrus amblycarpa) has been done. The purpose of this research is to process lime waste into raw material of pectin source, to know pectin quality of extract obtained, and characterization pectin using FTIR spectrum. To obtain the results of research conducted several stages of research are pectin extraction, pectin precipitation, pectin washing, pectin drying and continued with the characterization of pectin which includes determination of moisture content, ash content, equivalent weight, methoxyl content, galakturonat level, esterification degree and spectrum analysis FTIR to determine the absorption of pectin functional groups obtained. The results showed that the yield% was 11.72%, the water content was 11.40%, the ash content was 1.34%, the weight of the equivalent was 871.5, the metoxyl content was 5.66, the galactonate level was 64.48 %, degree of esterification equal to 49,84% and FTIR analysis result which have conformity with standard pectin group that has OH, CH aliphatic, C = O, CH3 and CO group (secondary alcohol, carboxylic, ester, ether).

Boosting biogas production from recalcitrant lignin-based feedstock by adding lignin-derived carbonaceous materials within the anaerobic digestion process

Lignocellulosic biomass can add to the worldwide resource of biogas; however, the aromatic structure of lignin is recalcitrant which impairs biodegradation. Direct interspecies electron transfer (DIET) may overcome limitations in the biodegradation of lignin derivatives. Within a circular bioeconomy system, lignin-derived biochar and activated carbon were assessed for their ability to enhance the digestion of a typical lignin monomer – syringaldehyde. Biochar at 5–10 g/L significantly reduced the lag-phase time by 33–42% possibly due to the enhancement of syntrophic hydrogenotrophic methanogenesis. In comparison, activated carbon at 1–10 g/L reduced the lag-phase time by 46–85% and significantly accelerated the degradation of volatile fatty acids, due to a combinational effect of enhanced syntrophic oxidation and DIET. When activated carbon was added at a higher dosage of 20 g/L, the highest biomethane yield (426.6 ml/g) was achieved; an increase of 33% compared to the digestion of syringaldehyde alone. The enhancement was ascribed to the metabolic shift from the hydrogenotrophic to the DIET pathway, which could be implied from the microbial community dominated by Methanosaeta. The superior function of activated carbon over biochar was speculated to be associated with its larger surface area and higher abundance of the CO group.

Effect of type 1 diabetes during pregnancy and lactation on neonatal hypoxia-ischemia injury and apoptotic gene expression.

Hypoxia-ischemia (HI) is one of the major disorders that causes a variety of abnormalities and infant mortality. Type 1 diabetes is one of the most common worldwide metabolic disorders, and its prevalence has become one of the public health concerns of the 21st century. This study aims to evaluate the effect of type 1 diabetes during pregnancy and lactation on vulnerability to neonatal HI in rats. Female Wistar rats (weighing 200 ± 220 g) were randomly assigned into two groups: Group 1 (rats that received 0.5mL/day of normal saline solution) and Group 2 (type 1 diabetes was induced in rats on the second day of pregnancy with a single dose of intraperitoneal injection of alloxan monohydrate [150 mg/kg]). After delivery, offspring were divided into four groups: (a) Control (Co), (b) Diabetic (DI), (c) Hypoxia-ischemia (HI), (d) HI + Diabetic (HI + DI). Seven days after HI induction, neurobehavioral tests were performed, and then cerebral edema, infarct volume, inflammatory factors, Bax-Bcl2 expression, and oxidative stress were measured. The BAX level in the DI + HI (p = 0.0355) group was significantly higher than the HI group. The Bcl-2 expression levels in the HI (p = 0.0027) and DI + HI (p < 0.0001) groups were significantly lower than the DI group. Total antioxidant capacity (TAC) levels in the DI + HI (p < 0.0001) group were significantly lower than HI and CO groups. TNF-α, CRP, and total oxidant status (TOS) levels in the DI + HI (p < 0.0001) group were significantly higher than the HI group. Infarct volume and cerebral edema in the DI + HI (p < 0.0001) group were significantly higher than the HI group. According to the results, type 1 diabetes during pregnancy and lactation increased the destructive effects of HI injury in pups. It also decreased the expression of the anti-apoptotic Bcl-2 and increased the expression BAX apoptosis factor gene in pups.

The photoactivity of complexation of DOM and copper in aquatic system: Implication on the photodegradation of TBBPA

The photoactivity of dissolved organic matter (DOM) has a great impact on the photodegradation of organic pollutants in natural waters. In this study, the photodegradation of TBBPA was investigated under simulated sunlight irradiation in the presence of copper ion (Cu2+), dissolved organic matter (DOM) and Cu-DOM complexation (Cu-DOM) to illustrate the effect of Cu2+ on photoactivity of DOM. The rate of photodegradation of TBBPA in the presence of Cu-DOM complex was 3.2 times higher than that in pure water. The effects of Cu2+, DOM and Cu-DOM on the photodegradation of TBBPA were highly pH dependent and hydroxyl radical(·OH) responded for the acceleration effect. Spectral and radical experiments indicated that Cu2+ had high affinity to fluorescence components of DOM, and acted as both the cation bridge and electron shuttle, resulting the aggregation of DOM and increasing of steady-state concentration of ·OH (·OHss). Simultaneously, Cu2+ also inhibited intramolecular energy transfer leading to the decrease of steady-state concentration singlet oxygen (1O2ss) and triplet of DOM (3DOM⁎ss). The interaction between Cu2+ and DOM followed the order of conjugated carbonyl CO, COO− or CO stretching in phenolic groups and carbohydrate or alcoholic CO groups. With these results, a comprehensive investigation on the photodegradation of TBBPA in the presence of Cu-DOM was conducted, and the effect of Cu2+ on the photoactivity of DOM was illustrated. These findings helped to understanding the potential mechanism of interaction among metal cation, DOM and organic pollutants in sunlit surface water, especially for the DOM-induced photodegradation of organic pollutants.

Synthesis of Hexahydropyrrolo-isoquinolines by 1,3-Dipolar cycloaddition of tetrahydroisoquinolines and cinnamaldehydes

A new method is described for the synthesis of hexahydropyrrolo-isoquinolines through the 1,3-dipolar cycloaddition of cinnamaldehydes with azomethine ylides generated from cinnamaldehydes and tetrahydroisoquinolines. The carbonyl CO groups of cinnamaldehydes serve as the precursor for the generation of azomethine ylides and the CC double bonds of cinnamaldehyde act as the dipolarophiles in the cycloaddition. The key features are easily available substrates, good functional group tolerance and mild reaction conditions. The relative configurations of products are confirmed by X-ray single crystal structure analysis, and a possible mechanism is proposed. A gram-scale experiment and some chemical transformations were conducted to show the synthetic utility of this approach. Finally, a plausible mechanism was proposed to clarify the formation of products with different configurations.

Role of alkane-[formula omitted],[formula omitted]-diamine in the nanostructure of carboxylic functionalized multiwalled carbon nanotubes grafted on amino-enriched nylon fabric toward metal ion absorption

Through a direct two-step functionalization reaction with alkane-α,ω-diamine (H2N(CH2)nNH2, n = 2, 4, 6, 8) and carboxylic functionalized multi-walled carbon nanotubes (MWCNT-COOH), the membrane labeled as C@(A[n]-nylon), is made up of nylon 6 fabric and intermediate amino-enriched nylon (A[n]-nylon) fabric. FTIR and Raman spectra confirm the efficient formation of amide bonds between the two amino heads of the alkane-α,ω-diamine, both with hydrolyzed nylon 6 and MWCNT-COOH. As a result, MWNCT-COOH were grafted to the nylon fiber side wall without causing damage to the nylon backbone. The SEM images confirm the plexus of MWCNT covering the amino-enriched nylon fibers. The long carbon chain of alkane-α,ω-diamine as an arm help amino groups reach beyond the surface of polyamide fiber, making it easier for -COOH groups of MWCNT-COOH to form amide bonds instead of being ejected when approaching CO groups on the polyamide surface. As-prepared C@(A8-nylon) membranes have metal ion rejection of more than 10% in vacuum filtration test with solution of M(CH3COO)2 (M = Ca, Co, Pb). Such membrane is long lasting for about 20 cycles, showing potential of turning polyamide fabrics with large pore sizes into highly efficient nanofiltration of reverse osmosis (RO) membranes. This unique structure opens up new possibilities for nanocomposite membranes and mass production by the proposed simple method.

Guanine adsorption on gold electrodes studied by in situ surface-enhanced infrared reflection absorption spectroscopy

The adsorption of guanine on single-crystal and thin-film gold electrodes has been explored by combination of cyclic voltammetry and ATR-SEIRA ‘in situ’ spectroscopy at two pD values (8 and 11.6) employing D2O as a solvent. The experimental conditions are selected to study the adsorption / desorption of the two forms of guanine involved in the second acid-base equilibria and its tautomeric forms.The ATR-SEIRA spectra of adsorbed guanine were compared to the absorption FT-IR spectra in solution and interpreted in light of DFT calculations of the different acid-base and tautomeric forms with different solvation states of the CO group. Furthermore, the preponderance of each tautomeric form and the possible changes in orientation with the electric field have been determined by analyzing the two-dimensional correlation spectrum (2D COS) as well as the influence of the potential on the integrated intensities of the spectral signals in the 1800–1400 cm−1 region. It has been found that at pD 8 the adsorbed keto-amino tautomer of neutral guanine predominates in solution and in adsorbed state, and adsorbed guanine slightly rotate its molecular plane with the potential. At pD 11.6 the keto-amino tautomer of anionic guanine is the unique form detectable in the solution, while in adsorbed state the keto-imino tautomeric form is also present with its preponderance increasing with the electrode potential.

Fabrication of highly oxidized Pt single-atom catalysts to suppress the deep hydrogenation of unsaturated aldehydes

In this work, we first reported the fabrication of single-atom Pt catalysts with high oxidation state through a mild hydrolysis method using platinum acetylacetonate as the precursor and SBA-15 coated with functional FeOx nanoclusters as support, and evaluate their catalytic performance towards unsaturated aldehydes hydrogenation. Pt1-FeOx/SBA-15 featuring the high coordination number of Pt-O exhibited markedly high selectivity for hydrogenation of CO group (> 95 %) when cinnamaldehyde conversion is 100 %, and further hydrogenation of target product could be efficiently inhibited over a prolonged period of time, and the universality of chemoselectivity was also evidenced in other unsaturated aldehydes. The experimental results and theoretical calculations revealed that the synergism of highly electron-deficient Pt single-atoms and FeOx species is responsible for the selectivity control and the inhibition of further hydrogenation. The developed strategy offers a facile approach to the rational design of high-efficient single-atom catalysts for the selective hydrogenation with multiple intermediates.

Selective furanyl ring hydrogenation of 5-hydroxymethylfurfural at sub-ambient temperature via steric effect on decorated Pd surfaces

It is a great challenge to synthesize the medical intermediate 5-hydroxymethyltetrahydrofurfural (HMTHF) from selective hydrogenation of 5-hydroxymethylfurfural (HMF), as the branched CO group is usually preferentially hydrogenated over active metal, e.g. Pd sites. Herein, we designed a surface-decorated Pd@NSi@Al2O3 catalyst and achieved selective hydrogenation of HMF, yielding 83.5% HMTHF at sub-ambient temperature (5 °C). Combination of experiments and DFT calculations verify the steric effect caused by the decoration of Pd surfaces led to larger bond lengths between O or C in –CHO ligand of HMF and the closest surface Pd sites. The total activation barrier for the hydrogenation reactions on the –CHO group of HMF becomes larger from 0.60 eV on Pd(111) to 0.83 eV on the cramped Pd(111). As a result, CC groups in the furanyl ring was preferentially hydrogenated over the branched CO of HMF. Furthermore, hydrogen bonds between the hydroxymethyl of the adsorbed HMF and the amine groups on Pd surfaces promote the adsorption of HMF and significantly increase the catalytic activity. Notably, this catalyst is robust and readily applicable in the furanyl ring hydrogenation of furfural and 5-methylfurfural. Overall, a controllable surface decoration strategy has been delivered that tailoring an efficient catalyst for selective hydrogenation of aromatic aldehyde.