Bimetallic Pt@Cu nanoparticles (NPs) with low Pt loading obtained by reducing platinum precursors on Cu NPs were coated on carbon paper and used as a cathode for asymmetric hydrogenation by the electrochemical method. The Pt@Cu NPs exhibited enhanced catalytic performance in ketone electrohydrogenation. The enantioselective electrohydrogenation of pro-chiral aromatic ketones (2,2,2-trifluoroacetophenone, acetophenone, 2-phenylacetone, 4-methylacetophenone) induced by cinchonidine alkaloids was investigated in an undivided cell to obtain optically active alcohols. Optically active α-(trifluoromethyl)benzyl alcohols with 59% enantiomeric excess and 25% yield were obtained. All experimental procedures were performed under mild conditions, that is, without the utilization of high temperature and pressure. The Pt@Cu NPs showed excellent stability and reusability.

A simple one-pot synthesis of Ni nanoparticle/ordered mesoporous carbon composite electrode materials is demonstrated for electrosynthesis for the first time. The obtained nanocomposites have uniform mesopore sizes (3.0–3.7 nm), large specific surface areas (506–633 m2 g−1), high pore volumes (0.28–0.38 cm3 g−1), well-graphitized carbon frameworks, and uniformly dispersed Ni nanoparticles (7–15 nm) embedded in the carbon pore walls. The prepared materials show very high performance in the selective (∼84%) electrocatalytic reduction of aromatic ketones into alcohols (∼79%).

A highly stable and recyclable catalyst, [PYD]@Cu–Pt, was demonstrated to have dual activity for electrochemical reduction of CO2 in aqueous solution. Different alcohol products could be obtained by simply switching the working potential. Through contrast experiments, a feasible reaction pathway was proposed to explain this dual activity.

A novel bifunctional catalyst, [PYD]@Cu–Pd composite, was synthesized for the first time and used as a cathode for electrochemical reduction of CO2. Methanol with 26% and ethanol with 12% Faradaic efficiency were obtained at the same [PYD]@Cu–Pd cathode using different potentials. Under both conditions, the [PYD]@Cu–Pd cathode shows remarkable stability and reusability.

•Asymmetric electrocatalytic hydrogenation was carried out on modified Cu electrodes.•Alkaloids were encapsulated within metallic Cu, alkaloid@Cu, instead of being physisorbed.•Alkaloid@Cu had a much higher activity than pure Cu NPs.•Alkaloid@Cu had excellent stability and reusability.A novel heterogeneous catalyst, alkaloid@Cu was prepared by the entrapment of commercially purchased alkaloids within non-noble metallic copper nanoparticles. This composite was compacted into a coin and directly used as cathode for electrocatalytic asymmetric hydrogenation of aromatic ketones. Using water as hydrogen source, optically active alcohols with 71% ee value and 93% yield were obtained under very mild conditions.

An Ag-ZSM-5/SS zeolite modified electrode has been prepared by a facile one-step method, during which Ag nanoparticles were formed in situ with a ZSM-5 film grown on a stainless steel substrate. The morphology and composition were characterized by XRD, SEM, TEM, EDX, H2-TPR, XPS, etc. Ag-ZSM-5/SS possessed much higher catalytic activity towards the electroreduction and electrocarboxylation of PhCH2Cl compared with an Ag bulk electrode.

The electroreduction behavior of bromostyrenes 1 in DMF has been detected by cyclic voltammetry (CV) on GC and Ag electrodes. Under the atmospheric pressure of CO2, selective electrocarboxylation of 1 was carried out in an undivided cell at Ag cathode under potentiostatic conditions, with the corresponding vinyl-benzoic acid methyl ester 3 as the principal product, accompanied by styrene 2. Moderate to good electrocarboxylation yields were obtained by preparative electrolysis. Synthetic parameters such as supporting electrolyte, applied potential, electric charge, and temperature, were found to influence the carboxylation efficiencies. Both CV and electrolysis confirm that the positions of C–Br and CC groups strongly affect the electrocarboxylation. Higher yields were obtained by changing from ortho to meta to para isomers.

A [PYD]@Pd composite was prepared by the entrapment of a pyridine derivative within metallic palladium. Metallic Pd acts as a heterogeneous support and a pyridine ring served as an active site for electroreduction of CO2, and no additional catalyst was needed in the electrolyte. 35% Faradaic efficiency of methanol was obtained at only −0.6 V vs. SCE. Moreover, [PYD]@Pd has remarkable stability and reusability.

A novel way to accommodate heterogeneous catalysis, CO2 fixation and asymmetric synthesis on one catalyst is reported. The [Co]@Ag composite was prepared for the first time and used for asymmetric carboxylation of benzyl bromides with CO2. All the procedures were performed under mild conditions. Moreover, the [Co]@Ag composite has terrific stability and reusability.

An alkaloid@Ag composite was prepared for the first time and used as a cathode for the enantioselective hydrogenation. Excellent yield and a remarkable enantiomeric excess value were obtained under mild conditions. Moreover, alkaloid@Ag after extraction was demonstrated to retain some chirality by linear sweep voltammetry.

•Enantiomerically pure cyclic carbonates were electrosynthesized under mild condition.•High conversion, selectivity and excellent ee value were obtained.•The regioselectivity has been firstly studied by the DFT calculation.•Electroreduced CO2 and Mg2 + played an important role in the synthesis process.In this paper, the one-step synthesis of enantiomerically pure cyclic carbonates has been developed by electrolyzing the chiral epoxides and CO2 (0.1 MPa, rt) in an undivided cell with a 316 stainless steel (SS) cathode and a Mg sacrificial anode containing TEAI–MeCN as supporting electrolyte and solvent with a constant current. To deeply understand this reaction, the effects of various synthesis conditions were investigated using R-styrene oxide as the model compound. Under the optimized conditions, the maximum conversion is 67% with 96% selectivity and 98.8% ee value for R-styrene carbonate. Finally, the reaction mechanism has been proposed by comparative electrolysis and DFT calculation.

•Cinchona alkaloids catalysis achieve enantioselective electrocarboxylation of racemic aromatic ketones.•The applications of CO2 enantioselective electrochemical fixation into optically active hydroxyl carboxylic acids have been expanded.•The applications of alkaloids have been expanded.•The applications of asymmetric synthesis by electrochemical methodology have been expanded.The enantioselective electrocarboxylation of pro-chiral aromatic ketones (2-acetonaphthone, 1-(6-methoxy-2-naphthyl)ethanone, 1-(4-methoxy-1-naphthyl)ethanone) with atmospheric pressure of CO2 catalyzed by cinchona alkaloids in the presence of phenol was investigated in an undivided cell for the first time to give optically active 2-hydroxy-2-arylpropionic acid. For the model compound 2-acetonaphthone, the influence of various reaction conditions, such as cathode material, current density, catalyst type, ratio of proton to catalyst and catalyst quantity, on the enantiomeric excesses (ee) and yield has been investigated. Under the optimized conditions of 2-acetonaphthone, all the aromatic ketones examined are converted into corresponding optically active 2-hydroxy-2-arylpropionic acids in moderate yield (32.2% - 41.3%) and ee (48.1% - 48.6%). In addition, the electrochemical behavior of 2-acetonaphthone has been studied by cyclic voltammetry (CV) in the absence and presence of CO2. Moreover, the probable reaction pathway was proposed accordingly.

•Electrogenerated chiral [CoI(salen)]− achieves asymmetric electrocarboxylation of a racemic organic halide.•Application of chiral CoII(salen) in electrochemical asymmetric fixation of CO2 has been developed.•Applications of asymmetric synthesis by electrochemical methodology has been expanded.The feasibility of asymmetric electrocarboxylation of 1-phenylethyl chloride catalyzed by the electrogenerated chiral [CoI(salen)]− complex has been investigated for the first time. Using this system, optically active 2-phenylpropionic acid in 37% yield and 83% ee is synthesized from 1-phenylethyl chloride and CO2. The electrochemical behavior of the catalyst and the optimization of synthesis conditions are discussed. This study provides a new procedure for the asymmetric synthesis of a chiral compound and expands the applications of chiral CoII(salen) in the electrochemical asymmetric fixation of CO2.

Cinchonine was demonstrated to be adsorbed on electrodeposited Ag for enantioselective hydrogenation. Moderate ee and excellent selectivity was obtained under mild conditions. The adsorption amount of cinchonine on the electrode was proved to be related to ee by HPLC.

CuO nanoparticles with five morphologies were synthesized in large quantities using a simple method. They were in situ reduced to metallic Cu for the electroreduction of CO2. Alcohols with excellent selectivity for ethanol were obtained. The specific morphology was demonstrated to be more electrocatalytically active than others by multiple methods.

The feasibility of the enantioselective electroreduction of pro-chiral acetophenone was investigated at the silver cathode in an undivided cell for the first time. Electroreduction of acetophenone in the presence of cinchonidine (CD) yielded two main products: the optically active alcohol, and the dimer product pinacol with no optical rotation. The influence of water in the co-solvent (MeCN/H2O), supporting electrolyte, electrode material, current density, and the alkaloid type on the enantiomeric excesses (ee) and yield was investigated. Under the optimized conditions, the alcohol was obtained with a 21.6% ee and a 3.6% yield, whereas, an 83.2% yield and a 5.5 dl/meso ratio were obtained for pinacol. The electrochemical behavior of the samples was also studied through cyclic voltammetry (CV). Finally, we proposed a possible induction mechanism based on the results of the electrolysis and CV.

Electroreduction behavior of three dibromobenzenes (1) has been investigated by cyclic voltammetry on glassy carbon and silver electrodes in DMF in the absence and presence of CO2. For meta- and para-dibromobenzenes, two successive two-electron reduction peaks could be detected, attributed to sequential cleavage of two reductive C–Br bond, while most of ortho-dibromobenzene underwent four-electron transfer reduction simultaneously. Related to distinguished electroreduction behaviors of three dibromobenzenes, distinct carboxylation rules were indicated. Both meta- and para-dibromobenzenes generally gave mono-carboxylation product of methyl bromobenzoate (3), while dehalogenated carboxylation product of methyl benzoate (2) was mainly obtained for the ortho-dibromobenzene. Moderate to good electrocarboxylation yields (49–74%) were obtained by preparative electrolyses in an undivided cell equipped with Mg rod as the sacrificial anode in the presence of CO2. Among the investigated electrode materials such as Ag, Cu, Ti and Ni, both cyclic voltammetry and confirmative electrolysis revealed the catalytic ability of Ag in the electroreduction and electrocarboxylation of dibromobenzenes.Highlights► We have studied the electroreduction behavior of three dibromobenzenes by cyclic voltammetry. ► The position of the Br atom on the benzene ring influences the peak potentials of the first reduction. ► For the distinguished electroreduction behavior, different carboxylated product ratios were obtained. ► It confirms the best catalytic ability of Ag among Ag, Ti, Ni and Cu materials.

The electrocarboxylation of a series of benzophenones under galvanostatic conditions has been carried out in aprotic solvents using an undivided bulk electrolysis cell equipped with a Mg sacrificial anode. Systematic studies have been carried out in order to establish the qualitative relationships between the yield of carboxylation reaction and the operational and intrinsic parameters for the electrocarboxylation of benzophenones. For the diaryl ketones chosen for these studies, the yields of the target benzilic acids have been found to be strongly dependent on different parameters such as solvents, supporting electrolytes, cathode materials, current density, temperature and the nature of the substrates.Highlights► A high yield electrocarboxylation system on benzophenones was established. ► Investigation of the effect of operative parameters on this process. ► We examine the effect of electron-donating groups of benzophenones on this process.

The alkaloid-induced electrocarboxylation of 4-methylpropiophenone is examined in mild conditions. Comparative studies with several inductors indicate that the efficient enantiodiscrimination of the electrocarboxylation depends on the nucleophilic quinuclidine nitrogen atom and the OH group of the inductors.

A voltammetric and electrolytic study involved in the electroreductive carboxylation of multi-substituted aliphatic coujugated dienes has been successfully conducted. With methyl sorbate as the modal compound, acceptable yields of carboxylation and dimerization were achieved, which were influenced by various reaction conditions such as the supporting electrolyte, cathode nature, current density, charge passed and temperature. A correlation was first established between distinct electronic effects of the dienes and the electrochemical characteristics of their reduction and the distribution law of target products.

An alkaloid@Ag composite was prepared for the first time and used as a cathode for the enantioselective hydrogenation. Excellent yield and a remarkable enantiomeric excess value were obtained under mild conditions. Moreover, alkaloid@Ag after extraction was demonstrated to retain some chirality by linear sweep voltammetry.

A novel bifunctional catalyst, [PYD]@Cu–Pd composite, was synthesized for the first time and used as a cathode for electrochemical reduction of CO2. Methanol with 26% and ethanol with 12% Faradaic efficiency were obtained at the same [PYD]@Cu–Pd cathode using different potentials. Under both conditions, the [PYD]@Cu–Pd cathode shows remarkable stability and reusability.

A novel way to accommodate heterogeneous catalysis, CO2 fixation and asymmetric synthesis on one catalyst is reported. The [Co]@Ag composite was prepared for the first time and used for asymmetric carboxylation of benzyl bromides with CO2. All the procedures were performed under mild conditions. Moreover, the [Co]@Ag composite has terrific stability and reusability.