Asymmetric acidic/alkaline N_(2)electrofixation accelerated by high-entropy metal-organic framework derivatives

High-entropy materials are composed of five or more metal elements with equimolar or near-equimolar concentrations within one crystal structure,which offer remarkable structural properties for many applications.Despite previously reported entropy-driven stabilization mechanisms,many high-entropy materials still tend to decompose to produce a variety of derivatives under operating conditions.In this study,we use transition-metal(Ni,Co,Ni,Zn,V)-based high-entropy metal-organic frameworks(HE-MOFs)as the precursors to produce different derivatives under acidic/alkaline treatment.We have shown that HE-MOFs and derivatives have shown favorable kinetics for N_(2)electrofixation in different pH electrolytes,specifically cathodic nitrogen reduction reaction in acidic media and anodic oxygen evolution reaction in alkaline media.To buffer the pH mismatch,we have further constructed an asymmetric acidic/alkaline device prototype by using bipolar membranes.As expected,the prototype showed remarkable activities,with an NH_(3)yield rate of 42.76μg h^(−1)mg^(−1),and Faradaic efficiency of 14.75%and energy efficiency of 2.59%,which are 14.4 and 4.4 times larger than those of its symmetric acidic and alkaline counterparts,respectively.

Single NIR Laser-Activated Multifunctional Nanoparticles for Cascaded Photothermal and Oxygen-Independent Photodynamic Therapy

Inconvenient dual-laser irradiation and tumor hypoxic environment as well as limited judgment of treating region have impeded the development of combined photothermal and photodynamic therapies(PTT and PDT).Herein,Bi2Se3@AIPH nanoparticles(NPs)are facilely developed to overcome these problems.Through a one-step method,free radical generator(AIPH)and phase transition material(lauric acid,LA,44-46°C)are encapsulated in hollow bismuth selenide nanoparticles(Bi2Se3 NPs).Under a single 808-nm laser irradiation at the tumor area,hyperthermia produced by Bi2Se3 not only directly leads to cell death,but also promotes AIPH release by melting LA and triggers free radical generation,which could further eradicate tumor cells in hypoxic environments.Moreover,Bi2Se3 with high X-ray attenuation coefficient endows the NPs with high computed tomography(CT)imaging capability,which is important for treating area determination.The results exhibit that Bi2Se3@AIPH NPs possesses 31.2%photothermal conversion efficiency for enhanced PTT,ideal free radical generation for oxygen-independent PDT,and 37.77 HU mL mg?1 X-ray attenuation coefficient for CT imaging with high quality.Most importantly,the tumor growth inhibition rate by synergistic PTT,PDT,and following immunotherapy is 99.6%,and even one tumor disappears completely,which demonstrates excellent cascaded synergistic effect of Bi2Se3@AIPH NPs for the tumor therapy.

Photorheologically reversible micelle composed of polymerizable cationic surfactant and 4-phenylazo benzoic acid

A photorheologically reversible micelle composed of polymerizable cationic surfactant n-cetyl dimethylallyl ammonium chloride(CDAAC) and trans-4-phenylazo benzoic acid(trans-ACA) was prepared.The effects of molar ratio of CDAAC/trans-ACA,time of UV and visible light irradiation and temperature on the rheological properties of micellar system were investigated.The results show that before UV irradiation the system with an optimum CDAAC/trans-ACA molar ratio of 1.4 forms viscoelastic micelles at 45 °C.After 365 nm UV irradiation,the viscosities of micelle systems with different concentrations at fixed molar ratio of 1.4 are decreased by 85%–95%.The CDAAC/trans-ACA(14 mmol·L-1/10 mmol·L-1) micelle system exhibits shear thinning property and its viscosity is decreased obviously with the increases of UV irradiation time less than 1 h.The rheological process during UV irradiation for CDAAC/trans-ACA(14 mmol·L-1/10 mmol·L-1) micelle proves that viscosity,elastic modulus G′ and viscous modulus G″ will reduce quickly with the UV light.Furthermore,the micelle system after 1 h UVirradiation is able to revert to its initial high viscosity with 460 nm visible light irradiation for 4 h,and the micelle can be cycled between low and high viscosity states by repetitive UV and visible light irradiations.The UV–Vis spectra of CDAAC/trans-ACA micelle indicate that its photosensitive rheological properties are related closely to photoisomerization of trans-ACA to cis-ACA.

Achieving Intrinsic Dual-Band Excitonic Luminescence from a Single Three-Dimensional Perovskite Nanoparticle Through Ni^(2+)-Mediated Halide Anion Exchange

Rapid halide anion exchange easily occurring in metal-halide perovskite nanoparticles(NPs)makes it nearly impossible to create a single three-dimensional(3D)CsPbX_(3)(X=Cl,Br,I)NP that simultaneously comprises two separate perovskite components.To circumvent this problem,we first propose a Ni^(2+)-mediated halide anion-exchange strategy in zero-dimensional(0D)Ni^(2+)-doped Cs_(4)PbBr_(6)(Cs_(4)PbBr_(6):Ni)perovskites to achieve ultra-stable 3D CsPbX_(3)NPs with two coexisting different perovskite individuals of CsPbCl_(3)and/or CsPbBr_(3).By combining the experimental results with first-principles calculations,we confirm that the completely isolated[PbBr_(6)]4−octahedra in 0D Cs_(4)PbBr_(6):Ni NPs can restrict rapid halide anion exchange and the anion diffusion preferentially proceeds in the proximity of substitutional NiPb centers,namely[NiBr_(6)]4−octahedra in a meta-stable state,rather than in the 0D Cs_(4)PbBr_(6)and residual 3D CsPbBr_(3)regions,thereby delivering intrinsic dual-band excitonic luminescence from a single 3D CsPbX_(3)NP with a more stable and efficient CsPbCl_(3)component as compared to its counterparts synthesized using conventional methods.These new insights regarding the precise control of halide anion exchange enable the preparation of a new type of high-efficiency perovskite materials with suppressed anion interdiffusion for prospective optoelectronic devices.

Tumor acid microenvironment-activated self-targeting&splitting gold nanoassembly for tumor chemo-radiotherapy

Low accumulation and penetration of nanomedicines in tumor severely reduce therapeutic efficacy.Herein,a pH-responsive gold nanoassembly is designed to overcome these problems.Polyethylene glycol linked raltitrexed(RTX,target ligand and chemotherapy drug)and two tertiary amine molecules(1-(2-aminoethyl)pyrrolidine and N,N-dibutylethylenediamine)are modified on the surface of the 6-nm gold nanoparticles by lipoic acid to form gold nanoassembly defined as Au-NNP(RTX).The Au-NNP(RTX)nanoassembly could remain at about 160 nm at the blood circulation(pH 7.4),while split into 6-nm gold nanoparticles due to tertiary amine protonation at tumor extracellular pH(pH 6.8).This pH-responsive disassembly behavior endows Au-NNP(RTX)better tumor tissue permeability through the better diffusion brought by the size reduction.Meanwhile,after disassembly,more RTXs on the surface of gold nanoparticles are exposed from the shielded state of assembly along with 2.25-fold augment of cellular uptake capability.Most importantly,the results show that Au-NNP(RTX)possesses of high tumor accumulation and effective tumor penetration,thereby enhancing the tumor chemo-radiotherapy efficiency.