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CuO/CeO2 catalysts were widely studied as an alternative to precious metal catalysts, and the Cu–Ce synergy was essential to improve the catalytic performance. In this paper, the effects of CuO loading on Cu–Ce synergy in CuO/CeO2 nanorod catalysts and their performance in toluene combustion were systematically investigated. It was found that non-equilibrium plasma facilitated the dispersion of CuO active species on the CeO2 surface. With the increase of the CuO loading from 1 wt% to 4 wt%, the Cu–Ce synergistic effect was gradually improved, which generated Cu+/Cu2+ and Ce3+/Ce4+ redox electron pairs. The highest oxygen vacancy concentration and Cu+ content of CuCe-4 (4 wt%) resulting from strong Cu–Ce synergy accelerated the activation of chemisorbed oxygen and consequently improved the efficiency of toluene catalytic combustion. [ABSTRACT FROM AUTHOR]

The performance of the oxygen reduction reaction (ORR) can be enhanced through the utilization of multi-heteroatom doped, porous, and layered electrocatalysts. Nitrogen-doped graphene-like porous carbon (Cu–Fe–CN) was synthesized via a simple and cost-effective NaCl template method using maltose, FeCl3·6H2O, and CuCl2·H2O as precursors. This material exhibits excellent electrocatalytic activity towards the ORR. During the electrocatalysis process, the maltose-derived graphene-like porous carbon possesses abundant pores that facilitate rapid mass and electron transfer. Additionally, the incorporation of polyatomic dopants and the construction of the porous carbon framework result in an abundance of active sites. The optimized Cu–Fe–CN electrocatalyst exhibited a more positive half-wave potential (E1/2 = 0.87 V) in alkaline media, surpassing that of the commercial Pt/C (E1/2 = 0.84 V), and demonstrated exceptional durability. The average discharge voltage of Al–air batteries with the Cu–Fe–CN catalyst is always higher than that of Al–air batteries with the commercial Pt/C catalyst, at the same current density. The present study showcases a convenient approach for fabricating porous low-metal catalysts for the ORR, highlighting their immense potential in ORR catalysis and aluminum–air batteries. [ABSTRACT FROM AUTHOR]

A detailed computational mechanistic study of the copper-catalysed three-component-type electrophilic carboamination of terminal alkynes with benzyne and an archetypal O-benzoylhydroxylamine electrophile is presented. Probing various plausible pathways for relevant elementary steps and scrutinising performance degradation pathways, with the aid of a reliable computational protocol applied to a realistic catalyst model combined with kinetic analysis, identified the pathways preferably traversed in productive catalysis. It entails rapid alkynylcupration of in situ generated benzyne to deliver the arylcopper nucleophile that undergoes amination with the O-benzoylhydroxylamine electrophile to afford copper benzoate. Umpolung-enabled electrophilic amination favours a multistep SN2-type oxidative addition/N–C bond-forming reductive elimination sequence involving a short-lived formal {P^P}CuIII carboxylate amido aryl intermediate. SN2-type displacement of the benzoate leaving group at the arylcopper nucleophile, which represents the catalyst resting state, is predicted to be the turnover limiting step. Alkynolysis transforms copper benzoate back to catalytically competent alkynylcopper. The computational probe of a wider range of substrates reveals that only severely ring-strained C6-arynes, C6-cycloalkynes and electron-deficient cyclopropenes featuring a highly reactive C≡C linkage could replace benzyne. Moreover, strict control of stationary benzyne concentration is indispensable for electrophilic carboamination to ever become achievable. [ABSTRACT FROM AUTHOR]

A new copper(II) bromide/N-methylmorpholine N-oxide (NMO)-promoted method for α-amination of esters under continuous-flow conditions, with reduced catalyst loading is reported. The α-amino esters are precursors for the synthesis of α-amino acids. This method provides α-amino esters in 58-83% yields. The desired Cu(II)Br catalyst is regenerated by in situ oxidation of Cu(I)Br in the presence of NMO. [ABSTRACT FROM AUTHOR]

Methanol steam reforming is considered as a potential hydrogen supply pathway, and Cu-based catalysts are commonly used catalysts for this reaction. A series of CZAT-x catalysts were synthesized, which are derived from Cu/ZnO/Al2O3 catalysts by modifying the method of introducing TiO2 in this study. Characterization techniques (BET, XRF, XRD, H2-TPR, N2O chemisorption, TEM, and XPS) revealed that the mode of TiO2 introduction primarily influences surface Cu dispersion, reducibility and Cu–Ti interaction, subsequently affecting CZAT-x catalysts' catalytic activity and thermal stability in methanol steam reforming. The TiO2-doped catalyst prepared through solvent-assisted ball milling demonstrated the highest activity. The complete conversion of methanol could be achieved under the conditions of a water-to-methanol ratio of 1.2 and a reaction temperature of 493 K, and the H2 time-space yield could reach 103.9 mol kg−1 h−1. Furthermore, even after 10 h of thermal treatment test at 723 K, the CZAT-EA catalyst maintained a high methanol conversion rate. [ABSTRACT FROM AUTHOR]

Plasma catalysis is recognized as a promising technology for the elimination of diluted volatile organic compounds (VOCs). In this study, a hybrid process was carried out using dielectric barrier discharge (DBD) and MCeZr/TiO2 (M = Cu, Mn, Ni, and Co) catalysts for the degradation of VOCs. The plasma-catalytic system demonstrated a substantial improvement in toluene conversion and CO2 selectivity compared to the plasma-only system owing to the synergistic effects of plasma and thermal catalysis on toluene degradation. The performance of toluene removal follows the sequence of CuCeZr/T > NiCeZr/T > CoCeZr/T > MnCeZr/T in plasma catalysis. The CuCeZr/T catalyst demonstrated the highest toluene conversion of 99.0% and a CO2 selectivity of 91.0% at a discharge power of 30 W. Energetic electrons and reactive species generated by plasma actively participate in toluene activation in the gas phase and facilitate adsorption on the catalyst surface. The redox properties between Ce4+/Ce3+ and Cu+/Cu2+ species dictated the reducibility of the CuCeZr/T catalyst, promoting oxygen cycling during toluene oxidation and leading to enhanced catalytic performance. The pathways of toluene destruction in the plasma-catalysis system are discussed based on the analysis results of GC–MS, optical emission spectroscopy and calculations of the electron-impact reactions. [ABSTRACT FROM AUTHOR]

Pd25Cu75@SiO2 core–shell and PdCu@SiO2@Cu core–shell–satellite architectures were fabricated by silica-coating of Pd25Cu75 colloids in a reverse microemulsion. Hydrolysis of tetraethylorthosilicate in the reverse microemulsion containing hydrazine and ammonia yielded a core–shell structure, while the use of ammonia only, instead of a mixture of hydrazine and ammonia, formed a core–shell–satellite structure. The ammonia-leached copper species migrated onto the developing silica shell and formed smaller Cu clusters. Air-calcination at 673 K followed by H2-reduction at 773 K of the as-synthesized samples removed the organic surfactants and generated the permeable porous silica shells. The core–shell catalyst consisted of a metal core (8.5 nm) and a silica shell (7.8 nm), while the core–shell–satellite catalyst was composed by a metal core (7.0 nm), a silica shell (8.0 nm), and satellite Cu clusters (1.4 nm) on the silica shell. When used to catalyze the selective hydrogenation of acetylene to ethylene, the core–shell–satellite catalyst showed substantially enhanced activity and stability because of the synergetic catalysis between the metal core and the surrounding Cu clusters. [ABSTRACT FROM AUTHOR]

Controlling the spatial selectivity of the coupling sites in two-molecule reactions is critical for stereoselective product synthesis. Herein, we report a novel strategy that uses basic ETS-10 zeolite-supported copper (Cu/ETS-10) as a catalyst for the highly selective synthesis of Z-3-methyleneisoindolin-1-ones in the absence of ligands. It was found that the rigidity of the zeolite skeleton was conducive to the high configurational selectivity of the product. The Cu/ETS-10 catalyst was easily recovered by simple filtration and could be reused five times without loss of its initial activity. [ABSTRACT FROM AUTHOR]

The construction of Cu–In bi-component catalysts is an effective strategy to enhance the electrocatalytic properties towards the CO2 reduction reaction (CO2RR). However, realizing the co-promotion of In and heteroatom P on the electrocatalytic performance is still a challenge due to the poor selectivity of metal phosphides. Herein, a novel bi-component catalyst (CuO–In(PO3)3/C) was successfully synthesized via a facile one-pot reaction to realize the integration of Cu, In, and P species for the enhancement of electrocatalysis. In particular, the as-obtained nanorod-like Cu–In(PO3)3/C exhibits superior electrocatalysis towards the CO2RR, with the highest Faraday efficiency of CO (FECO) of 88.5% at −0.586 V. Furthermore, Cu–In(PO3)3/C shows better activity, selectivity, and stability in the CO2RR; in particular, the total current density can reach 178.09 mA cm−2 at −0.886 V in 2.0 M KOH solution when a flow cell is employed. This work provides a reliable method for simplifying the synthesis of novel Cu-based catalysts and exploits the application of heteroatom P in the field of efficient CO2RR. [ABSTRACT FROM AUTHOR]

Cu/SAPO-34 is a highly efficient catalyst that can be used in various catalytic fields. However, the use of phosphoric acid during the preparation process exacerbates environmental pollution issues. This article uses aluminum phosphate as a new raw material and uses direct ion exchange to effectively control and reduce pollution in the process of preparing Cu/SAPO-34. A series of physical and chemical properties and catalytic performance of the catalyst were analyzed and studied using various characterization instruments. The results indicate that the Cu/SAPO-34 catalyst has more isolated Cu2+ and Cu[OH]+ sites than the Con-Cu/SAPO-34 catalyst prepared by traditional methods, and exhibits excellent ability to remove NOx in the temperature range of 100–550 °C. [ABSTRACT FROM AUTHOR]