Wenjun Yang

Bio: Wenjun Yang is an academic researcher from Nanjing Tech University. The author has contributed to research in topics: Umpolung & Carbene. The author has an hindex of 3, co-authored 5 publications receiving 918 citations.

Synergistic N-Heterocyclic Carbene/Palladium-Catalyzed Umpolung 1,4-Addition of Aryl Iodides to Enals

Abstract: An umpolung 1,4-addition of aryl iodides to enals promoted by cooperative (terpy)Pd/NHC catalysis was developed that generates various bioactive β,β-diaryl propanoate derivatives. This system is not only the first reported palladium-catalyzed arylation of NHC-bound homoenolates but also expands the scope of NHC-induced umpolung transformations. A diverse array of functional groups such as esters, nitriles, alcohols, and heterocycles are tolerated under the mild conditions. This method also circumvents the use of moisture-sensitive organometallic reagents.

Synthetic method of beta, beta-disubstituted propionate derivative

Abstract: The invention discloses a synthetic method of beta, beta-disubstituted propionate derivative, and belongs to the field of organic synthesis. An aldehyde compound, an iodide and an alcohol are adoptedto synthesize the beta, beta-disubstituted propionate derivative through a one-pot method, and the synthetic method is used for realizing beta-bit arylation and esterification of carbonyl groups of alpha, beta-unsaturated aldehyde to synthesize beta, beta-disubstituted methyl propionate. The synthesis steps of a traditional method are reduced, the reaction yield is increased, and according to thesynthetic method, raw materials are cheap, the operation steps are simple, the reaction condition is mild, and applicability of reaction substrates is greatly enriched.

Bulk COFs and COF nanosheets for electrochemical energy storage and conversion

Abstract: Covalent organic frameworks (COFs) as an emerging class of crystalline porous materials have received much attention due to their tunable porosity, modifiable skeletons, and atomically precise structures. Besides, COFs can provide multiple high-rate charge carrier transport (electron, hole, and ion) pathways, including conjugated skeletons, overlapped π electron clouds among the stacked layers, and open channels with a variable chemical environment. Therefore, they have shown great potential in electrochemical energy storage (EES) and conversion (EEC). However, in bulk COFs, the defects always impede charge carrier conduction, and the difficulties in reaching deep-buried active sites by either electrons or ions lead to limited performance. To overcome these obstacles, numerous research studies have been carried out to obtain COF nanosheets (NSs). This review first describes the preparation strategies of COF NSs via bottom-up and top-down approaches. Then, the applications of bulk COFs and COF NSs in EES and EEC are summarized, such as in batteries, supercapacitors, and fuel cells. Finally, key challenges and future directions in these areas are discussed.

Challenges in the material and structural design of zinc anode towards high-performance aqueous zinc-ion batteries

Abstract: Rechargeable aqueous metal-ion batteries are very promising as alternative energy storage devices during the post-lithium-ion era because of their green and safe inherent features. Among the different aqueous metal-ion batteries, aqueous zinc-ion batteries (ZIBs) have recently been studied extensively due to their unique and outstanding benefits that hold promise for large-scale power storage systems. However, zinc anode problems in ZIBs, such as zinc dendrites and side reactions, severely shorten the ZIB's cycle lifetime, thus restricting their practical application. Here, we sum up in detail the recent progress on general strategies to suppress zinc dendrites and zinc anode side reactions based on advanced materials and structure design, including the modification of the planar zinc electrode surface layer, internal structural optimization of the zinc bulk electrode, modification of the electrolyte and construction of the multifunctional separator. The various functional materials, structures and battery efficiencies are discussed. Finally, the challenges for ZIBs are identified in the production of functional zinc anodes.

Electrolyte Design for In Situ Construction of Highly Zn 2+ -Conductive Solid Electrolyte Interphase to Enable High-Performance Aqueous Zn-Ion Batteries under Practical Conditions.

Abstract: Rechargeable aqueous Zn-ion batteries promise high capacity, low cost, high safety, and sustainability for large-scale energy storage The Zn metal anode, however, suffers from the dendrite growth and side reactions that are mainly due to the absence of an appropriate solid electrolyte interphase (SEI) layer Herein, the in situ formation of a dense, stable, and highly Zn2+ -conductive SEI layer (hopeite) in aqueous Zn chemistry is demonstrated, by introducing Zn(H2 PO4 )2 salt into the electrolyte The hopeite SEI (≈140 nm thickness) enables uniform and rapid Zn-ion transport kinetics for dendrite-free Zn deposition, and restrains the side reactions via isolating active Zn from the bulk electrolyte Under practical testing conditions with an ultrathin Zn anode (10 µm), a low negative/positive capacity ratio (≈23), and a lean electrolyte (9 µL mAh-1 ), the Zn/V2 O5 full cell retains 944% of its original capacity after 500 cycles This work provides a simple yet practical solution to high-performance aqueous battery technology via building in situ SEI layers

Intrinsic Electrocatalytic Activity Regulation of M-N-C Single-Atom Catalysts for the Oxygen Reduction Reaction.

Abstract: Single-atom catalysts (SACs) with highly active sites atomically dispersed on substrates exhibit unique advantages regarding maximum atomic efficiency, abundant chemical structures, and extraordinary catalytic performances for multiple important reactions. In particular, M-N-C SACs (M=transition metal atom) demonstrate optimal electrocatalytic activity for the oxygen reduction reaction (ORR) and have attracted extensive attention recently. Despite substantial efforts in fabricating various M-N-C SACs, the principles for regulating the intrinsic electrocatalytic activity of their active sites have not been sufficiently studied. In this Review, we summarize the regulation strategies for promoting the intrinsic electrocatalytic ORR activity of M-N-C SACs by modulation of the center metal atoms, the coordinated atoms, the environmental atoms, and the guest groups. Theoretical calculations and experimental investigations are both included to afford a comprehensive understanding of the structure-performance relationship. Finally, future directions of developing advanced M-N-C SACs for electrocatalytic ORR and other analogous reactions are proposed.