Research Progress in Mechanochemistry of Inorganic Materials

With the progress of science and technology,China has gradually attached importance to research and exploration in chemistry,and the achievements in exploring mechanochemistry are also quite significant.Therefore,it is necessary to study and explore mechanochemistry.This article mainly discusses the application of mechanochemistry in powder and some silicate materials,as well as in special ceramics,and provides a brief introduction to provide reference for relevant researchers.

Unlocking the electrocatalytic activity of natural chalcopyrite using mechanochemistry

Manipulating the structure self-reconstruction of transition metal sulfide-based(pre)catalysts during the oxygen evolution reaction(OER) process is of great interest for developing cost-effective OER catalysts,which remains a central challenge. Here we realize a deep structure self-reconstruction of natural chalcopyrite to unlock its OER performance via mechanochemical activation. Compared with the manually milled counterpart(CuFeS_(2)-HM), the mechanically milled catalyst(CuFeS_(2)-BM) with a reduced crystallinity exhibits a 7.11 times higher OER activity at 1.53 V vs. RHE. In addition, the CuFeS_(2)-BM requires a low overpotential of 243 mV for generating 10 mA cm^(-2) and exhibits good stability over 24 h. Further investigations suggest that the excellent OER performance of CuFeS_(2)-BM mainly originates from the decreased crystallinity induced the in situ deep structure self-reconstruction of the originally sulfides into the electroactive and stable metal(oxy)hydroxide phase(e.g., a-Fe OOH) via S etching under OER conditions. This study demonstrates that regulating the crystallinity of catalysts is a promising design strategy for developing highly efficient OER catalysts via managing the structure self-reconstruction process, which can be further extended to the design of efficient catalysts for other advanced energy conversion devices. In addition, this study unveils the great potentials of engineering abundant natural minerals as cost-effective catalysts for diverse applications.

Solid-state mechanochemistry advancing two dimensional materials for lithium-ion storage applications:A mini review

The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical and flexibility properties,etc.Modern technologies for production of 2D materials include but are not limited to mechanochemical(solid-state/liquid-phase)exfoliation,the solvothermal method and chemical vapor deposition.In this review,strategies leading to the production of 2D materials via solid-state mechanochemistry featuring traditional high energy ball-milling and Sichuan University patented pan-milling are highlighted.The mechanism involving exfoliation,edge selective carbon radical generation of the 2D materials is delineated and this is followed by detailed discussion on representative mechanochemical techniques for tailored and improved lithium-ion storage performance.In the light of the advantages of the solid-state mechanochemical method,there is great promise for the commercialization of 2D materials for the next-generation high performance LIBs.

Mechanochemistry of catch bonds between integrins and ligands

Integrins are a large family of adhesion molecules broadly expressed on the surface of a wide variety of cells as heterodimers.Binding of integrins to ligands provides anchorage and signals for the cell,making them prime candidates for mechanosensing molecules.To elucidate how force regulates integrin/ligand dissociation,we used molecular mechanics experiments

Polymer Mechanochemistry on Reactive Species Generated from Mechanochemical Reactions

Comprehensive Summary Polymer mechanochemistry on reactive species has attracted more and more attentions over the past 20 years,as the mechanochemical generation of reactive species has a great potential in developing different polymeric materials for various purposes,such as stress detection,self-healing,self-strengthening,controllable degradation and release of small molecules.In this review,we first discuss the recent progress on polymer mechanochemistry of the reactive species that are generated from the mechanochemical reactions of mechanophores.Five types of reactive species,including radical,zwitterion,ionic,carbene and neutral intermediates,and their applications were reviewed in detail.Since mechanochemical reactions are sensitive to the mechanophore structure and polymer framework,we then discuss how mechanophore isomerism,polymer structure,polymer attachment point,and polymer architecture influence the mechanophore activation.At last,we provide our perspectives on the polymer mechanochemistry of reactivespecies.

Emerging Bio-relevant Applications of Polymer Mechanochemistry

Polymer mechanochemistry has rapidly evolved since the mid-20o0s.Recent advancements highlight the development of mechanophore platforms for the controlled release of bioactive payloads and the exploration of biocompatible activation strategies.These platforms,ranging from furan-maleimide Diels-Alder adducts to disulfide motifs withβ-carbonate linkages,demonstrate promising prospects in targeted drug delivery.Additionally,supramolecular assemblies and free radical-generating mechanophores present innovative avenues for potential therapeutic applications.Biocompatible activation methods,notably high-intensity and/or low-intensity focused ultrasound,hold potential for in vivo applications.However,challenges persist in comprehending the fundamental physics of ultrasound and its utilization for activation.

Mechanochemistry of cyclobutanes

The field of polymer mechanochemistry has been revolutionized by implementing force-responsive functional groups—mechanophores.The rational design of mechanophores enables the controlled use of force to achieve constructive molecular reactivity and material responses.While a variety of mechanophores have been developed,this Mini Review focuses on cyclobutane,which has brought valuable insights into molecular reactivity and dynamics as well as innovations in materials.We discuss its reactivity and mechanism,dynamics and stereoselectivity,as well as impacts on material properties.

Construction of conjugated scaffolds driven by mechanochemistry towards energy storage applications

Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized materials possessing promising properties.Among them,highly porous conjugated scaffolds with attractive electronic conductivities and high surface areas are one of the representative categories exhibiting diverse taskspecific applications,especially in electrochemical energy storage.In recent years,the mechanochemistry-driven procedures have been deployed to construct conjugated scaffolds with engineered structures and properties leveraging the tunability in chemical structures of building blocks and polymerization capability of diverse catalysts.Therefore,a thorough review of related works is required to gain an in-depth understanding of the mechanochemical synthesis procedure and property-performance relationship of the as-produced conjugated scaffolds.Herein,the mechanochemistry-driven construction of conjugated porous networks(CPNs),the carbon-based materials(e.g.,graphite and graphyne),and carbon supported single atom catalysts(CS-SACs)are discussed and summarized.The electrochemical performance of the afforded conductive scaffolds as electrode materials in supercapacitors and alkali-ion batteries is elucidated.Finally,the challenges and potential opportunities related to the construction of conjugated scaffolds driven by mechanochemistry are also discussed and concluded.

Reversible Mechanochemistry Enabled Autonomous Sustaining of Robustness of Polymers—An Example of Next Generation Self-healing Strategy

Even under low external force,a few macromolecules of a polymer have to be much more highly stressed and fractured first due to the inherent heterogeneous microstructure.When the materials keep on working under loading,as is often the case,the minor damages would add up,endangering the safety of use.Here we show an innovative solution based on mechanochemically initiated reversible cascading variation of metal-ligand complexations.Upon loading,crosslinking density of the proof-of-concept metallopolymer networks autonomously increases,and recovers after unloading.Meanwhile,the stress-induced tiny fracture precursors are blocked to grow and then restored.The entire processes reversibly proceed free of manual intervention and catalyst.The proposed molecular-level internal equilibrium prevention mechanisms fundamentally enhance durability of polymers in service.

Mechanochemistry and hydrogen storage properties of 2Li_(3)N+Mg mixture

The Li-Mg-N-H hydrogen storage system is a promising hydrogen storage material due to its moderate operation temperature,good reversibility,and relatively high capacity.In this work,the Li-Mg-N-H composite was directly synthesized by reactive ball milling(RBM) of Li3N and Mg powder mixture with a molar ratio of 2:1 under hydrogen pressure of 9 MPa.More than 8.8 wt%hydrogen was absorbed during the RBM process.The phases and structural evolution during the in situ hydrogenation process were analyzed by means of in situ solidgas absorption and ex situ X-ray diffraction(XRD) measurements.It is determined that the hydrogenation can be divided into two steps,leading to mainly the formation of a lithium magnesium imide phase and a poorly crystallized amide phase,respectively.The H-cycling properties of the as-milled composite were determined by temperature-programmed dehydrogenation(TPD) method in a closed system.The onset dehydrogenation temperature was detected at 125℃,and it can reversibly desorb 3.1 wt% hydrogen under a hydrogen back pressure of 0.2 MPa.The structural evolution during dehydrogenation was further investigated by in situ XRD measurement.It is found that Mg(NH_(2))_(2)phase disappears at about 200 ℃,and Li_(2)Mg_(2)N_(3)H_(3),LiNH_(2),and Li_(2)MgN_(2)H_(2)phases coexist at even 300 ℃,revealing that the dehydrogenation process is step-wised and only partial hydrogen can be desorbed.

Mechanochemistry in cancer cell metastasis

Metastasis is the leading cause of death in people with cancer. In the series of steps comprising metastasis process, mechanochemistry plays crucial roles. In this review, we introduced the mechanical factors in cancer cell metastasis, intracellular mechanical sensors and methods for measuring the mechanical forces of tumor cells. The recent researches on the contribution of mechanochemistry to metastasis and future perspectives were summarized.

A green repair pathway for spent spinel cathode material:Coupled mechanochemistry and solid-phase reactions

A way of directly repairing spent lithium-ion battery cathode materials is needed in response to environmental pollution and resource depletion.In this work,we report a green repair method involving coupled mechano-chemistry and solid-state reactions for spent lithium-ion batteries.During the ball-milling repair process,an added manganese source enters into the degraded LiMn_(2)O_(4)(LMO)crystal structure in order to fill the Mn vacancies formed by Mn deficiency due to the Jahn–Teller effect,thereby repairing the LMO's chemical composition.An added carbon source acts not only as a lubricant but also as a conductor to improve the material's electrical conductivity.Meanwhile,mechanical force reduces the crystal size of the LMO particles,increasing the amount of active sites for electrochemical reactions.Jahn–Teller distortion is successfully suppressed by cation disorder in the LMO material.The cycling stability and rate performance of the repaired cathode material are thereby greatly improved,with the discharge specific capacity being more than twice that of commercial LMO.The proposed solid-state mechanochemical in situ repair process,which is safe for the environment and simple to use,may be extended to the repair of other waste materials without consuming highly acidic or alkaline chemical reagents.

Mechanochemistry of an Interlocked Poly[2]catenane:From Single Molecule to Bulk Gel

Mechanically interlocked molecules(MIMs)are prototypical molecular machines with parts that enable controlled,large-amplitude movement with one component positioned relative to another.Incorporating MIMs into polymeric matrices is promising for the designing of functional materials with unprecedented properties.However,the central issue is the challenges involved with establishing the mechanistic linkage between the single-molecule and the bulk material.Herein,we explore the mechanochemical properties and energetic details of a linear poly[2]catenane with strong intercomponent hydrogen bonding(IHB)revealed by single-molecule force spectroscopy.Our results showed that the individual linear poly[2]catenane chain exhibited typical sawtooth pattern,corresponding to the reversible unlocking and relocking transitions under external force or upon stimulations to dissociate or re-form the strong IHB.Furthermore,when a poly[2]catenane-based polymer gel was prepared using a thiol-ene click reaction between thiol-ended poly[2]catenane and a low-molecule-weight cross-linker,the resultant gel showed excellent mechanical adaptability and dynamic properties,which correlated well with the molecular-level observations.The unique poly[2]catenane structure also contributed to the gel formation with an extraordinary IHB-mediated swelling behavior and shape memory property.Thus our present results demonstrate the functioning of bulk material in a linear tandem manner from the behavior of a single molecule,a finding which should be applicable to other systems with versatile properties and promising applications.

Fullerene Mechanochemistry:Serendipitous Discovery of Dumb-Bell-Shaped C_(120) and Beyond

The serendipitous discovery of dumb-bell-shaped C_(120) under high-speed vibration milling conditions is described.The mechanochemical protocol has been employed to synthesize the He-,H_(2)-or H_(2)O-encapsualted C_(120),the cross-dimer C_(130),trimer C_(180),bridged C_(60) dimers as well as products from many other reactions of fullerenes,carbon nanotubes and graphenes.Mechanochemistry extended to various reactions of non-fullerene molecules is briefly discussed.

Mechanochemistry enables optical-electrical multifunctional response and tunability in two-dimensional hybrid perovskites

Two-dimensional(2D)organic-inorganic hybrid perovskites(OIHPs)have attracted phenomenal attention because of their superior optoelectronic performances.The combination of their structural tunability and material stability offers an unprecedented opportunity to engineer materials with unique functionalities.However,developing a rapid and effective design method for introducing luminescence into dielectric switch and realizing controllable regulation has been an enormous challenge.Thus far,materials with tunable optoelectronic multichannel response have not been successfully implemented.In this study,we successfully developed a facile and effective mechanochemical method for realizing the integration and regulation of luminescence and dielectric switch in 2D perovskites,which is unprecedented for the design of dielectric switching materials.The mild external mechanical stimuli enabled the formation of Mn ion-doped 2D hybrid perovskites(Cyclopropylammonium)2Pb1-xMnxBr4 with excellent dielectric switch and rapidly controllable luminescence of highly efficient blue light,white light,pink light,and orange light.This work will provide a new perspective on the rapid and effective design of multifunctional materials and can inspire the future development of low-cost and high-efficiency electronics.

Highly defective HKUST-1 with excellent stability and SO_(2) uptake: The hydrophobic armor effect of functionalized ionic liquids

Water stability is one of the most important factors restricting the practical application of metal organic frameworks (MOFs). In this work, wefabricate a highly defective HKUST-1 framework with a mixed valence of CuI/CuIIby mechanical ball milling method. This defective HKUST-1is embellished by functionalized ionic liquids as hydrophobic armor, making the hybrid HIL1@HKUST-1 exhibits outstanding water stability,remarkable SO_(2) adsorption (up to 5.71 mmol g^(-1)), and record-breaking selectivity (1070 for SO_(2)/CO_(2) and 31,515 for SO_(2)/N_(2)) at 25 ℃ and0.1 bar, even in wet conditions.

Nitrogen-rich isoindoline-based porous polymer: Promoting knoevenagel reaction at room temperature

Nitrogen-rich porous organic polymers(POPs)with basic features have already shown promising performance in various organic reactions.But the harsh conditions,tedious synthetic methods and the requirement of specific monomers impede their further application.Herein,we introduce isoindoline chemistry into POP community.An isoindoline formation process between aniline and bromomethylbenzenedcoupling nucleophilic substitution,HBr elimination,and intramolecular cyclization in one pot,is utilized for POPs synthesis.Nitrogen-rich isoindolinebased porous polymers(IPPs)were obtained with specific surface areas up to 408 m^(2) g^(-1).Unexpectedly,mechanochemistry could enable the rapid(3 h)and solid-state synthesis of IPP catalysts.Moreover,this nitrogen-rich catalyst presents excellent activity(isolated yield:99%),scalable ability(up to 14 g per run)and recyclability(five runs)towards the Knoevenagel condensation reaction under mild reaction conditions(water as solvent at room temperature).

Structural macrokinetics of synthesizing ZnFe_2O_4 by mechanical ball milling

Powder mixtures of Fe2O3 and ZnO were milled in a high-energy planetary ball mill to synthesize ZnFe2O4 and X-ray powder diffractometry was used to obtain the relative content of phases,crystallite size and microstrain of both Fe2O3 and ZnFe2O4. The lattice constants of Fe2O3 were obtained by cell refinement method.The macrokinetics and the structure evolution of matters were studied and the results show that the dynamics process of mechanochemical synthesis of ZnFe2O4 fits Avrami-Erofe’ev model and is controlled by a nucleation-growth mechanism,and the structural macrokinetics theory in combustion synthesis research area could be used to describe the kinetic process as well.

Mechanochemical synthesis of oxygenated alkynyl carbon materials with excellent Hg(Ⅱ) adsorption performance from CaC2 and carbonates

Adsorptive removal of heavy metal ions from wastewater is very important,and the key is the development of efficient sorbents.In this work,oxygenated alkynyl carbon materials(OACMs)were synthesized via mechanochemical reaction of CaC_(2) and a carbonate(CaCO_(3),Na2CO_(3),or NaHCO_(3))at ambient temperature.The resultant OACMs are micro mesoporous carbon nanomaterials with high specific area(>648 m2 g^(-1)),highly crosslinked texture,and rich alkynyl and oxygenated groups.The OACMs exhibit excellent Hg(Ⅱ)adsorption due to the soft acid-soft base interaction between alkynyl and Hg(Ⅱ),and OACM-3 derived from CaC_(2) and NaHCO_(3) has the saturated Hg(Ⅱ)adsorbance of 483.9 mg g^(-1)along with good selectivity and recyclability.The adsorption is mainly chemisorption following the Langmuir mode.OACM-3 also shows high adsorbance for other heavy metal ions,e.g.256.6 mg g^(-1)for Pb(II),232.4 mg g^(-1)for Zn(II),and 198.7 mg g^(-1)for Cu(II).This work expands the mechnochemical reaction of CaC_(2)with carbonates and possibly other oxyanionic salts,provides a new synthesis approach for functional alkynyl carbon materials with excellent adsorption performance for heavy metal ions,as well as a feasible approach for CO2 resource utilization.

Characterization of the Microstructure Changes of Polypropylene Induced by Pan-milling

The microstructure changes of polypropylene induced by a complex combination of shearing, friction, compression and stretching actions during pan-milling were revealed by spectroscopic techniques. X-ray diffraction analysis showed that the structure of polypropylene transferred from crystal into amorphous after undergoing enough milling operation. No transformation between crystal forms was observed. The study of the high-frequency region of the Raman spectrum between 2800 and 3100cm-1 of polypropylene indicated that molecular motion and chain deformation of PP led to amorphization and deterioration of packing regularity during pan-milling. By co-panmilling PP with bis-(2,2,6,6-tetramethyl-4-piperidinyl) sebacate under ambient condition, ESR signals of free radicals formed by mechanochemical scission of main chain were observed, and an increase of ESR intensity with milling was detected.