A review on electrocatalytic CO_(2) conversion via C-C and C-N coupling

Electrochemical C-C and C-N coupling reactions with the conversion of abundant and inexpensive small molecules,such as CO_(2) and nitrogencontaining species,are considered a promising route for increasing the value of CO_(2) reduction products.The development of high-performance catalysts is the key to the both electrocatalytic reactions.In this review,we present a systematic summary of the reaction systems for electrocatalytic CO_(2) reduction,along with the coupling mechanisms of C-C and C-N bonds over outstanding electrocatalytic materials recently developed.The key intermediate species and reaction pathways related to the coupling as well as the catalyst-structure relationship will be also discussed,aiming to provide insights and guidance for designing efficient CO_(2) reduction systems.

Progress of fundamental mechanism of formic acid decomposition and electrooxidation

Formic acid(HCOOH) is considered as a promising viable fuel-cell ingredient for low temperature proton-exchange membrane fuel cells as a consequence of their high safety and energy density. As one prototype reaction, the study of HCOOH decomposition and electrooxidation is also helpful to understand the reaction mechanism of other small molecular organics. Herein, we present a comprehensive overview of HCOOH decomposition and electrooxidation in different environment conditions and analyze the reaction mechanism from both experimental and theoretical point of view. Furthermore, we discuss the known strategies for improving the performance of HCOOH decomposition and electrooxidation catalysts. Finally, this review presents a prospect for the future study of HCOOH decomposition and electrooxidation.

Morphological and crystallographic characteristics of lead powder obtained by electrodeposition from an environmentally friendly electrolyte

Lead powder obtained by potentiostatic electrodeposition from alkaline electrolyte, based on hydroxide ions, was investigated. The shape of lead crystals strongly depends on overpotentials of electrodeposition. The regular crystals are formed in the ohmic control. The shape of dendrites formed in the control of diffusion has a function of overpotentials of the electrodeposition. Increasing overpotential leads to branching of dendrites from primary type to those with developed tertiary branches. Formation of the very branchy dendrites of the strong （111） preferred orientation is explained on the basis of the affiliation of this electrolyte to the group of the complex Pb electrolytes.

AFM Height Measurements of Molecular Layers of a Carbocyanine Dye

Atomic force microscopy (AFM) was used for the morphological characterization and precise height meas-urements of two-dimensional molecular layers of carbocyanine dye 3,3’-di(r-sulfopropyl)-4,4’,5,5’-dibenzo-9-ethylthiacarbocyanine betaine pyridinium salt. The AFM measurements reveal three morphological types of molecular aggregates: leaves, stripes and spots. The leaves are stripes have same monolayer height ~1.4 nm and different crystal shapes: the leaves are monoloyers with the lens shape and the stripes are bilay-ers with the shape of extended rectangles. The monolayer height ~1.4 nm was interpreted as indicating the symmetrical packing arrangement of dye molecules. In the symmetrical monolayer, the sulfopropyl groups of all-trans monomer units are located on both monolayer sides whereas the adjacent stacked dye molecules have a lateral slippage providing the J-aggregate optical properties. The lower height of spots ~1 nm was explained by the model of an asymmetric monolayer with sulfopropyl groups of all-trans monomers occupy-ing the same position with respect to the monolayer plane. The packing arrangement of all-trans monomers in the asymmetric monolayer corresponds to H-aggregate. The alternative models of the packing arrange-ment in monolayers with mono-cis1 monomer configuration are discussed.

Sulfurized-polyacrylonitrile in lithium-sulfur batteries:Interactions between undercoordinated carbons and polymer structure under low lithiation

Lithium-sulfur battery(LSB)represents an important candidate to be used in energy storage applications,due to its high specific capacities.Sulfurized-polyacrylonitrile(SPAN)is a candidate as a host material in LSB to replace graphite,due to its ability to chemisorb polysulfides(PSs).The sulfur chains attached to the polymer can reversibly form Li2S,and SPAN indicates to have a good cyclability and better performance than graphite,thus,SPAN acts partially as an active and also as a host material.In this study,we investigated the capacity of the solvent or the SPAN to lose a hydrogen atom from the backbone,to predict possible anodic reactions between solvent and host material.The simulation suggests that the photophilic salts may preferentially react with the solvent,and possibly building a cathode electrolyte interphase(CEI).We observed that an undercoordinated carbon(C_(uc))can be thermodynamically created,due to lithiation.The Cuccan react with the solvent on the polymer backbone through different mechanisms,however,the simulations indicated that the reaction should be affected by the interaction between the solvent and C_(uc),according to SPAN’s configuration.Moreover,C_(uc)reacts with long sulfur chains attached to SPAN,capturing sulfur and forming a C-S bond.A sulfur chain from one SPAN can connect to another polymer backbone,however,this process is affected by lithiation and vice-versa.Therefore,this work also investigates the formation of interconnected SPAN structures and the multiple C_(uc)effects.

The pitfalls in electrocatalytic nitrogen reduction for ammonia synthesis

Ammonia synthesis by electrocatalytic nitrogen reduction reaction(EC-NRR)has gained momentum in recent years fueled by its potential to operate at ambient conditions,unlike the highly energyintensive yet long-standing Haber-Bosch process.However,the large disparity of the yields and Faradic efficiencies reported for EC-NRR raises serious concerns about the reliability of the experimental results.In this perspective,we elaborate on the potential sources of error when assessing EC-NRR and update the testing protocols to circumvent them,and more importantly,we pose a general call for consensus on ammonia production analysis and reporting to lay the solid foundations that this burgeoning field requires to thrive.

Glycerol Electrooxidation to Value-Added C_(1)-C_(3)Chemicals:Mechanism Analyses,Influencing Factors,Catalytic Regulation,and Paired Valorization

Glycerol,as a byproduct of biodiesel production,can be used to produce a variety of high-value C_(1),C_(2),and C_(3)chemicals by electrocatalytic glycerol oxidation reaction(EGOR).Further coupling EGOR with CO_(2)reduction reaction(CO_(2)RR)or hydrogen evolution reaction(HER)in paired electrolyzers is increasingly attractive due to the reduced input energy for the simultaneous formation of value-added products on both sides of the cell.This review article introduces the main reaction path of EGOR and the influencing factors of the reaction conditions of EGOR.The catalysts for the highly selective formation of glyceric acid,lactic acid,tartaric acid(TA),or formic acid(FA)from EGOR are highlighted.The latest research progress on design strategies of catalysts required for these reactions was reviewed.Subsequently,the paired electrolyzers coupling EGOR with HER or electrocatalytic CO_(2)RR were evaluated.Finally,the challenges and prospects in the field of EGOR are pointed out to move forward with the future development of glycerol electrocatalysis.