In situ establishment of Co/MoS_(2) heterostructures onto inverse opal‐structured N,S‐doped carbon hollow nanospheres:Interfacial and architectural dual engineering for efficient hydrogen evolution reaction

Rational design of low‐cost and high‐efficiency non‐precious metal‐based catalysts toward the hydrogen evolution reaction(HER)is of paramount significance for the sustainable development of the hydrogen economy.Interfacial manipulationinduced electronic modulation represents a sophisticated strategy to enhance the intrinsic activity of a non‐precious electrocatalyst.Herein,we demonstrate the straightforward construction of Co/MoS_(2) hetero‐nanoparticles anchored on inverse opal‐structured N,S‐doped carbon hollow nanospheres with an ordered macroporous framework(denoted as Co/MoS_(2)@N,S-CHNSs hereafter)via a templateassisted method.Systematic experimental evidence and theoretical calculations reveal that the formation of Co/MoS_(2) heterojunctions can effectively modulate the electronic configuration of active sites and optimize the reaction pathways,remarkably boosting the intrinsic activity.Moreover,the inverse opal‐structured carbon substrate with an ordered porous framework is favorable to enlarge the accessible surface area and provide multidimensional mass transport channels,dramatically expediting the reaction kinetics.Thanks to the compositional synergy and structural superiority,the fabricated Co/MoS_(2)@N,S-CHNSs exhibit excellent HER activity with a low overpotential of 105mV to afford a current density of 10 mA/cm^(2).The rationale of interface manipulation and architectural design herein is anticipated to be inspirable for the future development of efficient and earth‐abundant electrocatalysts for a variety of energy conversion systems.

Intrinsic electrochemical activity of Ni in Ni_(3)Sn_(4) anode accommodating high capacity and mechanical stability for fast-charging lithium-ion batteries

Fast interfacial kinetics derived from bicontinuous three-dimensional(3D)architecture is a strategic feature for achieving fast-charging lithium-ion batteries(LIBs).One of the main reasons is its large active surface and short diffusion path.Yet,understanding of unusual electrochemical properties still remain great challenge due to its complexity.In this study,we proposed a nickel–tin compound(Ni_(3)Sn_(4))supported by 3D Nickel scaffolds as main frame because the Ni_(3)Sn_(4) clearly offers a higher reversible capacity and stable cycling performance than bare tin(Sn).In order to verify the role of Ni,atomic-scale simulation based on density functional theory systematically addressed to the reaction mechanism and structural evolution of Ni_(3)Sn_(4) during the lithiation process.Our findings are that Ni enables Ni_(3)Sn_(4) to possess higher mechanical stability in terms of reactive flow stress,subsequently lead to improve Li storage capability.This study elucidates an understanding of the lithiation mechanism of Ni_(3)Sn_(4) and provides a new perspective for the design of high-capacity and high-power 3D anodes for fast-charging LIBs.

Fluorinated inverse opal carbon nitride combined with vanadium pentoxide as a Z-scheme photocatalyst with enhanced photocatalytic activity

In this work,Z-scheme V_(2)O_(5) loaded fluorinated inverse opal carbon nitride(IO F-CN/V_(2)O_(5)) was synthesized as a product of ternary collaborative modification with heterostructure construction,element doping and inverse opal structure.The catalyst presented the highest photocatalytic activity and rate constant for degradation of typical organic pollutants Rhodamine B(RhB)and was also used for the efficient removal of antibiotics,represented by norfloxacin(NOR),sulfadiazine(SD)and levofloxacin(LVX).Characterizations confirmed its increased specific surface area,narrowed bandgap,and enhanced visible light utilization capacity.Further mechanism study including band structure study and electron paramagnetic resonance(EPR)proved the successful construction of Z-scheme heterojunction,which improved photogenerated charge carrier migration and provide sufficient free radicals for the degradation process.The combination of different modifications contributed to the synergetic improvement of removal efficiency towards different organic pollutants.

Delicate synthesis of quasi-inverse opal structural Na_(3)V_(2)(PO_(4))_(3)/N-C and Na4MnV(PO_(4))_(3)/N-C as cathode for high-rate sodium-ion batteries

Poor conductivity and sluggish Na^(+) diffusion kinetic are two major drawbacks for practical application of sodium super-ionic conductor(NASICON) in sodium-ion batteries. In this work, we report a simple approach to synthesize quasi-inverse opal structural NASICON/N-doped carbon for the first time by a delicate one-pot solution-freeze drying-calcination process, aiming at fostering the overall electrochemical performance. Especially, the quasi-inverse opal structural Na_(3)V_(2)(PO_(4))_(3)/N-C(Q-NVP/N-C) displayed continuous pores, which provides interconnected channels for electrolyte permeation and abundant contacting interfaces between electrolyte and materials, resulting in faster kinetics of redox reaction and higher proportion of capacitive behavior.As a cathode material for sodium-ion batteries, the Q-NVP/N-C exhibits high specific capacity of 115 mAh·g^(-1) at 1C, still 61 mAh·g^(-1) at ultra-high current density of 100C,and a specific capacity of 89.7mAh·g^(-1) after 2000 cycles at 20C.This work displays the general validity of preparation method for not only Q-NVP/N-C,but also Na_(3)V_(2)(PO_(4))_(3),which provides a prospect for delicate synthesis of NASICON materials with excellent electrochemical performance.

Fluorescence Retention of Organosilane-polymerized Carbon Dots Inverse Opals in CuCl Suspension

A novel and fluorescence retention inverse opal has been achieved from organosilane-polymerized carbon dots（SiCDs）, which is prepared via infiltrating SiCD solution into the interstice of photonic crystal（PC） template, low temperature treatment, heating polymerization and removing the colloidal template. The as-prepared SiCD inverse opals demonstrate close-cell structure, which is completely different from conventional open-cell structure. Then the fluorescence signal of as-prepared sample keeps almost unchanged in CuCl suspension while the fluorescence of SiCD solution can be quenched by CuCl suspension through an effective electron transfer process. This phenomenon can be attributed to the combined effect of high hydrostatic pressure in the pore structure, stable crosslinking network and fluorescence enhancement by PC structure. The SiCD inverse opals have advantages of unique close-cell structure, easy preparation and good repeatability that give an important insight into the design and manufacture of novel and advanced optical devices.