Strain-Driven Phase Transitions in Delafossite Cu1-xAxAlO2: A Key to Enhanced Photo(electro)catalytic Performance.

This study investigates the impact of intrinsic strain and phase transitions on the thermodynamic stability and electronic properties of Cu1-xAxAlO2 solid solutions, which are key to their photocatalytic performance. It is demonstrated that Cu1-xAxAlO2 with A = Ag, Au, Pt can form continuous isostructural solid solutions due to relatively small compressive strain, while a substantial increase strain restricts Cu1-xPdxAlO2 to forming only limited solutions. For A = Li, Na, the formation of heterostructural solid solutions is facilitated by structural motif alterations, accommodating significant differences in ionic radii and A-O bond characteristics. Specifically, Cu1-xLixAlO2 exhibits a phase transition at x ≈ 0.333, whereas Cu1-xNaxAlO2 undergoes three distinct phase transitions. Electronic structure analysis indicates that in Cu1-xAxAlO2 (A = Ag, Au), d10-d10 closed-shell interactions dominate, enabling tunable band gaps with varying solubility. Nevertheless, increased intrinsic strain in metal sublattices, as seen in A = Pd and Pt, shifts antibonding states to the Fermi level, inducing a semiconductor-to-metal transition. Experimental evidence confirms that Ag+ ions modulate the band gaps and carrier dynamics in Cu1-xAgxAlO2, with Cu0.75Ag0.25AlO2 exhibiting heightened photoelectrochemical activity and a 38.5-fold enhancement in H2 production rate over CuAlO2. Additionally, the coordination environment changes between alkali metals and O, induced by phase transitions, effectively tune the band edge positions and carrier dynamics of Cu1-xAxAlO2 (A = Li, Na) heterostructural solid solutions. Therefore, 3R-Cu0.97Li0.03AlO2 with asymmetric nonlinear dumbbell O-Cu-O demonstrates the highest photocatalytic H2 production activity, 72.9 times greater than CuAlO2. In contrast, α-Cu1-xAxAlO2 with a smaller CuO6 octahedral splitting energy exhibits increased band gaps, resulting in diminished photocatalytic activity. This research underscores that strain-driven phase transition provides an additional control factor and new mechanism for regulating the photo(electro)catalytic activity of Cu1-xAxAlO2 solid solutions.

Tuning electronic structure for enhanced photocatalytic performance: theoretical and experimental investigation of CuM1-xM'xO2 (M, M' = B, Al, Ga, In) solid solutions.

This study introduces robust screening methodology for the efficient design of delafossite CuM1-xM'xO2 solid-solution photocatalysts using band-structure engineering. The investigation not only reveals the formation rules for various CuM1-xM'xO2 solid solutions but also highlights the dependence on both lattice compatibility and thermodynamic stability. Moreover, the study uncovers the nonlinear relationship between composition and band gaps in these solid solutions, with the bowing coefficient determined by the substitution constituents. By optimizing the constituent elements of the conduction band edge and adjusting solubility, the band structure of CuM1-xM'xO2 samples can be fine-tuned to the visible light region. Among the examined photocatalysts, CuAl0.5Ga0.5O2 exhibits the highest H2 evolution rate by striking a balance between visible-light absorption and sufficient reduction potential, showing improvements of 28.8 and 6.9 times those of CuAlO2 and CuGaO2, respectively. Additionally, CuGa0.9In0.1O2 demonstrates enhanced electron migration and surpasses CuGaO2 in H2 evolution due to a reduction in the effective mass of photogenerated electrons. These findings emphasize the pivotal role of theoretical predictions in synthesizing CuM1-xM'xO2 solid solutions and underscore the importance of rational substitution constituents in optimizing light absorption, reduction potentials, and effective mass for efficient hydrogen production.

Novel lignans from Zanthoxylum nitidum and antiproliferation activity of sesaminone in osimertinib-resistant non-small cell lung cancer cells.

Seven previously undescribed tetrahydrofuran lignans with different configurations and unusual isopentenyl substitutions, nitidumlignans D-J (corresponding to compounds 1, 2, 4, 6, 7, 9 and 10), along with 14 known lignans, were isolated from Zanthoxylum nitidum. Notably, compound 4 is an uncommon naturally occurring furan-core lignan derived from tetrahydrofuran aromatization. The antiproliferation activity of the isolated compounds (1-21) was determined in various human cancer cell lines. The structure-activity study revealed that the steric positioning and chirality of the lignans exert important effects on their activity and selectivity. In particular, compound 3 (sesaminone) exhibited potent antiproliferative activity in cancer cells, including acquired osimertinib-resistant non-small-cell lung cancer (HCC827-osi) cells. Compound 3 also inhibited colony formation and induced the apoptotic death of HCC827-osi cells. The underlying molecular mechanisms revealed that 3 downregulated the activation of the c-Met/JAK1/STAT3 and PI3K/AKT/mTOR signaling pathways in the HCC827-osi cells. In addition, the combination of 3 and osimertinib exhibited synergistic effects on the antiproliferative activity against HCC827-osi cells. Overall, these findings inform the structure elucidation of novel lignans isolated from Z. nitidum, and sesaminone was identified as a potential compound for exerting antiproliferative effects on osimertinib-resistant lung cancer cells.

[Sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine].

Two sample pretreatment methods of pesticide residues in Panax notoginseng of Chinese traditional medicine were developed. For Method I, the residues were extracted from homogenized tissue with n-hexane-dichloromethane (6:4) by means of ultrasonication, the crude extract was purified by an Envi-carb/NH2 solid-phase extraction (SPE) column. For Method II, matrix solid-phase dispersion (MSPD) technique was used for extracting and cleaning up. The eluates were concentrated by rotary evaporation, and then were redissolved in dichloromethane prior to GC-MS determination. The determination was performed in selected ion monitoring (SIM) mode with the external calibration for quantitative analysis. Under the optimal conditions, the results indicated that the methods are easier and faster, the recoveries of method I for the spiked standards at concentration of 0.01, 0.5, and 2.0 mg x kg(-1) were 81.90%-102.10% with the relative standard deviations (RSDs) of 3.60%-7.10%. The recoveries of method II were 96.26%-104.20% with the RSDs of 3.52%-7.94%. The detection limits (S/N) for residues of pesticides were in the range of 0.48-1.34 ng x g(-1). The results indicated that these multiresidue analysis methods can meet the requirements for determination of residue pesticides and can be appropriate for trace analysis of residue pesticides in Panax notoginseng.