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The incorporation of two-dimensional (2D) functional nanosheets in polymeric membranes is a promising material strategy to overcome their inherent performance trade-off behavior. Herein, we report a novel nanocomposite membrane design by incorporating MXene, a 2D sheet-like nanoarchitecture known for its advantageous lamellar morphology and surface functionalities, into a cross-linked polyether block amide (Pebax)/poly(ethylene glycol) methyl ether acrylate (PEGMEA) blend matrix, which delivered exceptional CO2/N2and CO2/H2separation performances that are critical to industrial CO2capture applications. The finely dispersed Ti3C2Txnanosheets in the blend polymer matrix led to an expansion of the free volume within the resultant mixed matrix membrane (MMM), giving rise to a substantially enhanced CO2permeability of up to 1264.6 barrer, which is 102% higher than that of the pristine polymer. Moreover, these MXene-incorporated MMMs exhibited preferential sorption for CO2over light gases, which contributed to an exceptional CO2/N2and CO2/H2selectivity (64.3 and 19.2, respectively) even at a small loading of only 1 wt %, allowing the overall performance to not only surpass the latest upper bounds but also exceed many previously reported high-performance nanosheet-based nanocomposite membranes. Long-term performance tests have also demonstrated the good stability of these membranes. This composite membrane design strategy reveals the remarkable potential of combining a blend copolymer matrix with ultrathin MXene nanosheets to achieve superior gas separation performance for environmentally important gas separations.

The polar $\beta $ -phase of polyvinylidene fluoride (PVDF) is the characteristic crystal phase of ferroelectric, pyroelectric, and piezoelectric, and it is also the strongest crystal dipole moment perpendicular to the chain direction. A single high-polarity solvent (dielectric constant >15) can increase the dipole arrangement of PVDF molecular chains, but its internal hydrogen atoms bind other atoms firmly, which makes it difficult for PVDF to obtain more active phases. Herein, adopting the low-polarity solvents as transition solvents by the “nucleophilic substitution” can easily promote the formation of dipole–dipole bonds between the “transition state” PVDF and polar solvents. Meanwhile, the continuous vacuum crystallization method is used to weaken the rapid dispersion of solvent due to heating, and a controlled process of forming a fixed crystalline phase structure from the “transition state” is achieved. The pressure sensor possesses excellent charge density (4.375 nC/cm2), sensitivity ( ${S}$ = 0.175 V/N), and stability due to high piezoelectric property ( $\text{d}_{{33}} \sim $ 35 pC/N) at the volume ratio (acetone: DMF = 8:2). The sensor is potential in detecting the mechanical motion, body signals (pronounce, breathing state, and finger tapping), and the applicability of dyspnea diseases.

The integration of structural design and compositional modulation has been a hotspot for the optimization of electrocatalytic properties due to their synergistic effect. However, the details of this synergistic effect still lacks deep study. Herein, we fabricated an Ni2P/Ni5P4electrocatalyst with a Janus nanostructure embedded in N-doped carbon through a controllable phosphidation approach. The as-obtained hybrid catalyst realized an overpotential of 104 mV and Tafel slope of 38.5 mV dec−1, which were smaller than that of the single Ni2P and Ni5P4, at a current density of −10 mA cm−2in 0.5 M H2SO4electrolyte. To reveal the reasons for the promotion of electrocatalytic properties, the synergistic effect was analyzed with the difference charge density (DCD), density of state (DOS), ΔGH*, and strength of the internal electric field (IEF) on the interface between Ni5P4and Ni2P. The results indicated that the composite structures could optimize the ΔGH*due to the change in the DOS instead of DCD. Further calculations indicated that the composite structure could modify the effective electric field, which is often overlooked and may be the reason for the change in the DOS. This study provides new insight for designing multi-component catalysts and deeply illuminating a part of the synergistic effect for high-efficiently electrocatalytic activities.

“Outstanding” electrocatalysts towards oxygen evolution reaction (OER) are springing up at present, to the extent that one questions if most nanomaterials are inherently highly active electrocatalysts. The answer is negative, for certain easy-to-ignore data processing errors could lead to potential misjudgment of electrocatalytic activity. Combing through 100 highly cited papers (ESI 1% in Web of Science) concerning OER published in the latest three years, the applications of uncompensated potential (iRs)-correction rates are severely inconsistent. Herein, taking the benchmarks RuO2and IrO2as model catalysts, the authors investigated the effects of various iRs-correction rates on OER performance (overpotential, Tafel slope, and turnover frequency). The unanticipated discoveries maybe provoke a reexamination of those reported “great” OER electrocatalysts as well as help draw attention to the iRs-correction rates in the field of electrocatalysis.

The insufficient separation of photogenerated charge carriers and faint CO2capture remains the major obstacles for photocatalytic conversion of CO2into solar fuel. Rational design of semiconductor photocatalysts with unique structures may be promising to break this bottleneck. Herein, bismuth rich Bi4O5B2hollow microspheres are designed as a robust photocatalyst for efficient CO2reduction. Thanks to the bismuth rich strategy, the highly dispersed band structure and the elevated conduction band (CB) potential facilitate the charge transfer and photoreduction ability. Meanwhile, hollow structure provides the large specific area and creates a resonance in its interior to enhance the CO2adsorption and activation. Benefiting from the collaborative promotion effect, the local charge arrangement and electronic structure are tuned so as to an exceptional efficiency of photocatalytic CO2conversion into CO (3.16 μmol g−1 h−1) and CH4(0.5 μmol g−1 h−1) is attained over hollow Bi4O5Br2, which is superior to that of solid Bi4O5Br2and BiOBr, as well as other reported Bi-based photocatalysts. This work paves new opportunities for exploring high-efficiency CO2photoreduction catalysts.