Science China Chemistry最新文献

Developing high-performance catalysts for dry reforming of methane (DRM) requires balancing activity, stability, and carbon resistance. Here, we reported a high-entropy oxide (HEO) nanosheet catalyst, (Mg_0.4Fe_0.2Co_0.2Ni_0.2)Al₂O₄, synthesized via a solvent-free citrate-assisted route, which achieved exceptional DRM performance. The HEO nanosheets exhibited outstanding activity at 750 °C, with CH₄ and CO₂ conversions exceeding 89% and 92%, respectively, while maintaining stability for >400 h—far surpassing sol-gel-derived counterparts (CH₄/CO₂ conversions <77%/84% within 6 h) and Ni-only catalysts (CH₄/CO₂ <72%/81% in 14 h). Post-reduction, FeCoNi ternary alloy nanoparticles are exsolved from the HEO matrix, combining high metal dispersion with strong interfacial interactions. Density functional theory (DFT) calculations revealed that the upward shift of the d-band center in FeCoNi (−1.59 eV) compared to pure Ni (−2.42 eV) enhanced charge transfer to reactants, weakening C-H and C-O bonds. This electronic modulation, coupled with the nanosheet morphology, suppressed sintering and carbon deposition, as evidenced by negligible mass loss (98% retention) after 400 h. Raman and TEM analyses confirmed that the HEO nanosheets resisted graphitic carbon formation, unlike conventional catalysts plagued by fibrous coke. This work demonstrates how HEO-derived alloy catalysts synergize structural robustness and electronic optimization to advance DRM technology.

Despite the rapid development of organic light-emitting diodes (OLEDs) in the field of displays, obtaining deep-blue OLEDs with high efficiency, small full-width at half-maximum (FWHM), and low efficiency roll-off is still a challenge. Herein, we report a new strategy to develop an efficient and narrow-band deep-blue emitter based on tetradentate Pt(II), labeled PtKW1; this approach involved increasing the ³LE character of the lowest triplet state (T₁) by extending the π conjugation in the carbazole moiety, followed by locking the N-heterocyclic carbene (NHC) and phenyl moiety with a six-membered alkyl ring, aiming to enhance the molecular rigidity. Satisfactorily, PtKW1 showed a low Huang-Rhys factor (S_M) value of 0.285 and an FWHM of only 18.4 nm in dichloromethane at room temperature. Furthermore, a PtKW1-doped exciplex host film exhibited a quantum efficiency of up to 99% and a short excited state lifetime of 3.17 μs. A PtKW1-doped deep-blue OLED achieved an FWHM of 26 nm, Commission Internationale de l’Eclairage (CIE) coordinates of (0.125, 0.189), a maximum luminescent brightness (L_max) of up to 41074 cd/m², and a maximum external quantum efficiency (EQE_max) of 27.4%, with a low-efficiency roll-off rate of only 1.46% at 1000 cd/m². This work provides new insights for designing robust, narrow-band tetradentate Pt(II) emitters to develop highly efficient and stable deep-blue OLEDs with low efficiency roll-off and high luminescence.

Herein, we report a novel, visible-light-induced approach for the selective construction of both gem-difluoroalkenes and trifluoromethyl alkanes from α-trifluoromethyl olefins using alcohol-derived N-alkoxyphthalimides as alkyl radical precursors. This strategy leverages Eosin Y as a photocatalyst in a defluorinative alkylation reaction and a catalyst-free electron donor-acceptor (EDA) complex-mediated hydroalkylation process. By modulating the reaction conditions, the desired products were selectively obtained with excellent chemo-selectivity and in high yields. The protocol accommodates a wide variety of substrates, including primary, secondary, and tertiary alcohols, as well as diverse α-trifluoromethyl styrenes, and is applicable to late-stage functionalization of natural products and bioactive molecules.

The electrosynthesis of hydrogen peroxide (H₂O₂) has been widely considered as an environmentally friendly and sustainable alternative to the conventional anthraquinone protocol. Covalent organic frameworks (COFs) have emerged as promising metal-free catalysts for oxygen reduction reaction (ORR) processes. The designable molecular structures of COFs render adjustable catalytic selectivity towards two-electron (2e⁻) ORR pathway for the electrosynthesis of H₂O₂. Here, we synthesized a viologen-linked cationic COF, namely PTBD, via Zincke reaction using a conventional solvothermal strategy. To investigate the correlation between the structure and the catalytic performance, imine-linked neutral COFs of PTBP and PBBP with varying heteroatom nitrogen contents are prepared via Schiff-base condensation reaction. Notably, the PTBD COF, which is constructed by di-cationic viologen linkages and triazine blocks, delivers an exceptional H₂O₂ selectivity of ~92%, considerably surpassing the imine-bridged neutral PTBP (~30%) and PBBP (~78%) COFs. Theoretical calculations are performed to uncover how the thermodynamic tendency of PTBD COF towards 2e⁻ ORR route is related to its proper activation of O₂. This work highlights the role of linkage and heteroatom contents in COFs regarding the catalytic selectivity, paving a way for designing metal-free catalysts for the selective electrosynthesis of H₂O₂.

Poly(ester amide)s (PEAs) represent promising biomaterials because of their well-balanced mechanical properties, biodegradability, and biocompatibility. However, practical applications of PEAs are still limited by challenges in functional versatility and environmental adaptability. Here, we present the first synthesis of periodic selenium-incorporated PEAs (Se-PEAs) via a rapid, catalyst-free selenol-yne click polymerization process. By harnessing the versatility of selenium, we achieved precise modulation of material properties. The resulting Se-PEAs demonstrated tunable mechanical behavior, spanning rigid plastics to elastomers, alongside exceptional thermal stability and high optical clarity. Programmable degradation profiles ensure long-term stability in physiological environments while facilitating rapid oxidative degradation at the end of the lifecycle. Surface selenoniumization further conferred robust antibacterial efficacy without compromising mechanical integrity. This multifunctionality positions Se-PEAs as transformative materials for biomedical implants, sustainable packaging, and high-refractive-index optics. Our work advanced functional polymer design and underscored the potential of selenium chemistry in addressing global challenges in terms of plastic waste and ecological sustainability.

Rationally regulating the adsorption strength of reaction intermediates on the surface of copper-based electrocatalysts would influence the product selectivity in the electrochemical CO₂ reduction reaction (eCO₂RR). Herein, theoretical screening results reveal that among the twelve metals, Mg, Al, Cr, Mn, Fe, Co, Ni, Zn, Sn, Bi, Mo and Ce, the introduction of the metals Bi, Ce, Mg and Mn into CuOOH nanosheets not only modulates the Cu active center, but also leads to a certain degree of conformational distortion, resulting in an increased occupation of electrons in the antibonding state and accelerating the formation of the rate-determining step *HCOO. In situ spectroscopies combined with theoretical calculations confirm that Bi atoms modulate the electronic structure of Cu and enhance CO₂ activation, while Cu sites promote the adsorption of *HCOO intermediate, significantly increasing the formation of HCOOH with Faradaic efficiency exceeding 90% on the CuBiOOH. Moreover, the introduction of Mn into CuOOH nanosheets can induce the formation of key intermediates (*CHO and *CO), leading to enhanced asymmetric C-C coupling to generate ethanol. Our work provides deep insights into the structural regulation strategy of Cu sites at the atomic scale for converting CO₂ to liquid chemical products.

The development of power conversion efficiency (PCE) for organic solar cells (OSCs) based on polymer donors with benzo[1,2-b:4,5-b′]-difuran building block is slower than that of those based on benzodithiophene due to uncontrollable aggregation behavior. However, the former is expected to be more promising in realizing environmentally friendly and high-performance devices. Thereby, a smart aggregation tuning strategy is needed for boosting the efficiency of this type of OSCs. Here we report solid additives designed by self-imitation strategy, which aims to control the aggregation of the donor D18-Fu, and regulate the domain expansion of the acceptor L8-BO. Three oligomeric additives, with or without halogenation, can uniformly reduce the energy loss and enhance charge generation compared to an additive-free control device. This improvement is demonstrated through a series of morphological characterizations, photophysical analyses and theoretical simulations, indicating strong interaction between additive molecules and donor & acceptor. As a result, a 19% PCE is reported in binary OSCs, which also represents the highest level for devices based on benzo[1,2-b:4,5-b′]-difuran core contained polymer donor. Apart from high performance, our study provides new insights into manipulating the competition between the donor and acceptor’s pure phase formation through new additive design methods.

This study presents a novel polyoxometalate (POM) constructed crystalline inorganic framework, featuring a 2D layered architecture with irregular porosity and inherent proton sources. This unique configuration establishes an intrinsic hydrogen bonding network that facilitates proton hopping (Grotthuss mechanism), achieving a [100] directional proton conductivity of 1.75×10⁻3 S cm⁻¹ under a low relative humidity (RH) of 35% at 298 K. Notably, under elevated conditions (338 K, 95% RH), it attains a superprotonic conductivity of 1.61 S cm⁻¹, representing one of the highest values recorded for framework materials to date. Analysis of the molecular structure, pore geometry characteristics and topological connectivity, and water vapor adsorption experiment (offering proton diffusion coefficient), indicates that the exceptional water-mediated proton dynamics stem from the interlayer S-shaped irregular pore channels, which probably induce a siphon-like effect to significantly enhance the transport of hydrated protons under the vehicle mechanism. This work not only proposes a POM strategy for constructing 2D inorganic frameworks but also reveals the irregular pore channel-enhanced proton dynamics, providing new insights into the optimization of proton conductors.

Antibiotic pollutants have become a global environmental challenge, with tetracycline (TC) antibiotics posing a severe threat to ecosystems due to their widespread use and resistance to degradation. In this study, InVO₄ nanocrystals were synthesized using a microwave-assisted hydrothermal method. By applying a band engineering strategy, a Z-scheme heterojunction was constructed by combining InVO₄ with BiVO₄, and reduced graphene oxide (rGO) was introduced to create a BiVO₄/rGO/InVO₄ ternary photocatalyst for the efficient degradation of TC. Structural characterization and theoretical calculations indicate that the construction of the Z-scheme heterojunction facilitates the spatial separation of photogenerated charge carriers while maintaining a high redox potential of the system (with a photocurrent density of 3.46 mA/cm²). The rGO, acting as an electron transfer bridge, significantly enhances the interface charge transfer rate and material stability. The optimized ternary system exhibits degradation rate constants for TC that are 3.9 times higher than BiVO₄, 21.5 times higher than InVO₄, and 1.8 times higher than BiVO₄/InVO₄ photoanodes, maintaining stable catalytic activity after five cycles. Liquid chromatography-mass spectrometry analysis of the intermediate product evolution and toxicity assessments together verify the ecological safety of the degradation process. Density functional theory calculations combined with electron paramagnetic resonance measurements confirm that the oxidation path primarily driven by the synergistic action of h⁺, ·OH and ·O ⁻₂ radicals is the main mechanism for pollutant degradation. This study aims to develop an efficient and stable photocatalytic system by constructing a Z-scheme heterojunction composite system with a two-dimensional conductive medium, providing a theoretical basis and technical solution to address key issues such as low mass transfer efficiency and insufficient oxidation capacity in antibiotic pollution remediation.