Recent advances in catalytic conversion of carbon dioxide to propiolic acids over coinage-metal-based catalysts

The conversion of inexpensive,available C1 feedstock of carbon dioxide(CO_(2))into value-added fine chemicals via homogeneous or heterogeneous catalysis has attracted great recent interest.Coinagemetal-based(Cu,Ag,and Au)catalysis has emerged as a synthetic strategy for a wide range of organic chemical reactions in past decades.In coinage-metal-catalyzed carboxylation,CO_(2)is adopted as a carboxylation reagent,while coinage-metal salts,complexes,and nanoparticles(NPs)serve as a Lewis acid catalyst to activate unsaturated chemicals,particularly alkynes.This mini-review focuses on the recent advances of coinage-metal-catalyzed carboxylation of terminal alkynes with CO_(2).Other respects,such as the role of bases,the influence of trace water,and solvent effects are also highlighted.

Balancing the anionic framework polarity for enhanced thermoelectric performance in YbMg_(2)Sb_(2) Zintl compounds

1-2-2-type Zintl phase compound has aroused great interest for potential thermoelectric applications.However,YbMg_(2)Sb_(2) is seldom studied due to the very low electrical conductivity resulting from the large difference in the electronegativity between Mg and Sb.In this paper,we adjust the covalently bonded network of MgeSb by replacing part of the Mg with Zn which has the electronegativity closer to that of Sb.The decreased polarity in the anionic framework offers more free distance for electrons for the enhanced Hall mobility and electrical conductivity.Together with the increased point defect and the decreased lattice thermal conductivity by introduction of Zn,the maximum ZT value of ~0.8 at 773 K is achieved in YbMg_(0.9)Zn_(1.1)Sb_(2) which is~100% enhancement compared with that of YbMg_(2)Sb_(2).

Recent advances of two-dimensional CoFe layered-double-hydroxides for electrocatalytic water oxidation

Oxygen evolution reaction(OER)is pivotal to drive green hydrogen generation from water electrolysis,but yet is strictly overshadowed by the sluggish reaction kinetics.Earth-abundant and cut-price transitionmetal compounds,particularly Co Fe layered-double-hydroxides(LDHs),show the distinct superiorities in contrast to noble metals and their derivatives.In this review,we firstly underline their fundamental issues in electrocatalytic water oxidation,including Co Fe LDHs crystal structure,the surface of(hydr)oxides confined to OER and the controversial roles of Fe species,aiming at understanding the structure-related activity and catalytic mechanism.Advanced approaches for optimizing OER activity of Co Fe LDHs are then comprehensively overviewed,which will shed light on the different working mechanisms and provide a concise analysis of their unique advantages.Finally,a perspective on the future development of Co Fe LDHs electrocatalysts is offered.We hope this review can give a concise and explicit guidance for the development of transition-metal-based electrocatalysts in the energy field.

Iontronic pressure sensor with high sensitivity and linear response over a wide pressure range based on soft micropillared electrodes

Electronic skins and flexible pressure sensors are important devices for advanced healthcare and intelligent robotics.Sensitivity is a key parameter of flexible pressure sensors.Whereas introducing surface microstructures in a capacitive-type sensor can significantly improve its sensitivity,the signal becomes nonlinear and the pressure response range gets much narrower,significantly limiting the applications of flexible pressure sensors.Here,we designed a pressure sensor that utilizes a nanoscale iontronic interface of an ionic gel layer and a micropillared electrode,for highly linear capacitance-to-pressure response and high sensitivity over a wide pressure range.The micropillars undergo three stages of deformation upon loading:initial contact(0-6 k Pa)and structure buckling(6-12 k Pa)that exhibit a low and nonlinear response,as well as a post-buckling stage that has a high signal linearity with high sensitivity(33.16 k Pa-1)over a broad pressure range of 12-176 k Pa.The high linearity lies in the subtle balance between the structure compression and mechanical matching of the two materials at the gel-electrode interface.Our sensor has been applied in pulse detection,plantar pressure mapping,and grasp task of an artificial limb.This work provides a physical insight in achieving linear response through the design of appropriate microstructures and selection of materials with suitable modulus in flexible pressure sensors,which are potentially useful in intelligent robots and health monitoring.

Boosting pH-Universal Hydrogen Evolution of Molybdenum Disulfide Particles by Interfacial Engineering

The design of high-efficiency non-noble and earth-abundant electrocatalysts for hydrogen evolution reaction(HER)is highly paramount for water splitting and renewable energy systems.Molybdenum disulfide(MoS_(2))with abundant edge sites can be utilized as a promising alternative,but its catalytic activity is greatly related to the pH values,especially in an alkaline environment due to the extremely high energy barriers for water adsorption and dissociation steps.Here we report an exceptionally efficient and stable electrocatalyst to improve the sluggish HER process of layered MoS_(2)particles in different pH electrolytes,especially in base.The electrocatalyst is constructed by in situ growing selenium-doped MoS_(2)(Se-MoS_(2))nanoparticles on three-dimensional cobalt nickel diselenide(mCo_(0.2)Ni_(0.8)Se_(2))nanostructured arrays.Due to the large number of active edge sites of Se-MoS_(2)particles exposed at the surface,robust electrical conductivity and large surface area of mCo_(0.2)Ni_(0.8)Se_(2)support,and strong interfacial interactions between Se-MoS_(2)and mCo_(0.2)Ni_(0.8)Se_(2),this hybrid catalyst shows very outstanding catalytic HER properties featured by low overpotentials of 30 and 122 mV at 10 and 100 mA/cm^(2)with good operational stability in base,respectively,which outperforms most of inexpensive catalysts consisting of layered MoS_(2),transition metal selenides and sulfides,and it performs as well as noble Pt catalysts.Meanwhile,this electrocatalyst is also very active in neutral and acidic electrolytes,requiring low overpotentials of 93 and 94 mV at 10 mA/cm^(2),respectively,demonstrating its superb pH universality as a HER electrocatalyst with excellent catalytic durability.This study provides a straightforward strategy to construct an efficient non-noble electrocatalyst for driving the HER kinetics in different electrolytes.