Three-dimensional lily-like CoNi_2S_4 as an advanced bifunctional electrocatalyst for hydrogen and oxygen evolution reaction

Designing low-cost, highly efficient, and stable bifunctional electrocatalysts for both hydrogen evolution reaction（HER） and oxygen evolution reaction（OER） is of vital significance for water splitting.Herein, three-dimensional lily-like CoNi_2S_4 supported on nickel foam（CoNi_2S_4/Ni） has been fabricated by sulfuration of the Co–Ni precursor. As expected, CoNi_2S_4/Ni possesses such outstanding electrocatalytic properties that it requires an overpotential of only 54 mV at 10 mA cm^（-2） and 328 mV at 100 mA cm^（-2） for HER and OER, respectively. Furthermore, by utilizing the CoNi_2S_4/Ni electrodes as bifunctional electrocatalysts for overall water splitting, a current density of 10 mA cm^（-2） can be obtained at a voltage of only 1.56 V.

The Cyclization Reactions of Lawesson's Reagent with Bifunctional Substrates

The cyclizaion reactions of Lawesson's reagent(LR) with the substrates containing two functional groups such as hydroxy groups,amino groups, has been applied to prepare the O-P-O,N-P-N type 5-membered and 6-membered phosphorus heterocycles.The heterocyclizaional possibility of LR with bifunctional compounds was also discussed.

Low-Temperature Working Feasibility of Zinc–Air Batteries with Noble Metal-Free Electrocatalysts

Expanding the application scenario for rechargeable batteries is the key to the terminal utilization of renewable energy.Enabling zinc–air batteries at low temperatures is drawing increasing attention,yet the low-temperature working feasibility of zinc–air batteries with noble metalfree electrocatalysts remains indistinct.In this contribution,the low-temperature performances of zinc–air batteries with noble metal-free electrocatalysts are comprehensively investigated.Armed with a representative noble metal-free bifunctional oxygen electrocatalyst,the zinc–air batteries demonstrate satisfactory yet relatively depressed performance at low temperatures,compared with that at room temperatures.The reduced electrolyte conductivity is identified as one of the limiting factors for the reduced low-temperature performance.Furthermore,electrolyte engineering via solvation structure regulation is performed on the zinc–air batteries with noblemetal-free electrocatalysts,where an improved low-temperature performance is achieved.This work reveals the compatibility between noble metal-free electrocatalysts and low-temperature feasibility/low-temperature performance enhancement strategies for zinc–air batteries and affords new opportunities to satisfy low-cost and efficient energy storage at harsh working conditions.

Lamellar-assembled PdNi super-nanosheets as effective oxygen redox dual-electrocatalysts for rechargeable Zn-air batteries

Exploration of bifunctional electrocatalysts toward effective oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is pivotal for developing high-efficiency and rechargeable metal-air batteries but remains great challenging.Here we elaborately synthesize lamellar-assembled PdNi super-nanosheets(SNSs)with an optimized Pd/Ni molar ratio to serve as attractive ORR and OER bifunctional electrocatalysts for rechargeable high-powered Zn-air batteries(ZABs).The products are layer-by-layer stackings of ultrathin PdNi nanosheet motifs.On the drastically extended two-dimensional(2D)surface,the inserted Ni atoms can substantially lower down the d-band center of surface Pd toward improved ORR kinetics and concurrently create oxytropic NiOx sites to adsorb–OH groups for promoting the reverse OER electrocatalysis.Specifically,the ORR mass activity and specific activity of the primary Pd_(92)Ni_(8)SNSs attain 2.5 A·mg^(−1)and 3.15 mA·cm^(−2),which are respectively 14 and 9 times those of commercial Pt/C.Meanwhile,the OER activity and stability of Pd_(92)Ni_(8)SNSs/C distinctly outperform those of the RuO_(2)benchmark,suggesting excellent reversible oxygen electrocatalysis.The power density of the ZAB with Pd_(92)Ni_(8)SNSs/C as the air cathode is 2.7 times higher than that by Pt/C benchmark.Significantly,it can last for over 150 h without significant performance degradation during the charge–discharge cycle test.This work showcases a feasible strategy for developing self-assembled multimetallic 2D nanomaterials with excellent bifunctional catalytic performances toward energy conversion applications.

Phosphine-mediated enantioselective synthesis of carbocycles and heterocycles

Nucleophilic chiral phosphine catalysis has been prosperous in asymmetric synthesis over the past two decades. Various tunable chiral phosphines display excellent activity and selectivity in asymmetric transformations including acycloaddition reactions and cycloaddition reactions. Enantiomerically enriched cyclic compounds are ubiquitous in natural products and drug molecules. These phosphinecatalyzed reactions provide effective and extensive strategies for the synthesis of a series of complex cyclic compounds as well as the synthesis of chiral compounds which could be easily transformed to carbocycles and heterocycles. This minireview summarizes recent developments in this area and highlights meaningful breakthroughs.