Photocatalytic conversion of O2 and H2O provides a green and low-cost route for H2O2 synthesis; however, most reaction systems involve sacrificial agents, and achieving efficient photosynthesis of H2O2 in pure water remains a challenge. In this work, a Z-scheme Bi2S3/ZnIn2S4 heterojunction with rich sulfur defects was prepared by a one-step hydrothermal method. The combination of Bi2S3 with ZnIn2S4 greatly enhanced visible-light absorption. The intimate heterojunction interface bonded through sulfur bridge efficiently promoted the separation and migration of photogenerated carriers. Moreover, the enlarged specific surface area, the existence of sulfur defects and the increase of surface hydrophobicity facilitated the oxygen reduction reaction. As a result, the H2O2 production rate of the Bi2S3/ZnIn2S4 heterojunction in pure water under visible light reached 1,634 μmol·g-1·h-1, which was 5.3 and 43.0 times that of ZnIn2S4 and Bi2S3, respectively. This work provides new ideas for the construction of novel heterojunction photocatalysts for H2O2 production.
Phosphine-containing porous organic polymers are candidate materials that could realize heterogenization of the homogeneous phosphine-metal catalysts. However, their succinct synthesis from the commercialized phosphines directly is still a challenge. This work pioneers a Brønsted acid-catalyzed molecular Lego assembly, enabling modular construction of fluorinated phosphine-containing polymers (FPPs) from commercial building blocks - aryl phosphines or their metal complexes - in one step. By simply introducing a third molecular-Lego module with rigid skeleton (e.g., spirobifluorene, triptycene), the porosity of FPPs can be precisely engineered while maintaining good to high yields (60%-98%), demonstrating the plug-and-play versatility of this strategy. This work presents the synthesis of 18 different structures of FPPs with distinct structures. Among them, the Ru complex-derived FPPs-10 shows excellent CO2 uptake capability (1.15 mmol·g-1 at 0 °C) and exhibits exceptional performance in N-formylation reaction: high activity (turnover number up to 1.41 × 105), and good stability (reused at least for 5 cycles), while maintaining broad alkylamine compatibility. Overall, this work establishes a molecular Lego-like assembly paradigm for the on-demand design and regulation of phosphine-based heterogeneous catalysts.
Deep eutectic solvents (DESs) offer a sustainable and effective strategy for lignin fractionation from biomass, improving the efficiency of enzymatic hydrolysis. However, the downstream utilization of the lignin extracted in high yield through DES is a difficult problem. Herein, this work employed a novel acidic DES with phenolic modifiers to investigate their dual role in lignin extraction and structural modification, aiming to optimize the production of phenolic compounds via pyrolysis. The result showed that the choline chloride/formic acid/phenol DES with a molar ratio of 1:2:0.05 exhibited an excellent lignin extraction efficiency when pretreated at 120 °C for 6 h, and the recovered lignin maintained a high β-O-4 content, decreased molecular weight, and low char yield. High yield and selectivity of alkyl phenols were obtained by pyrolysis of the regenerated lignin extracted under the optimal pretreatment conditions. The low-condensed lignin easily generated phenolic compounds after pyrolysis. After five cycles of reuse, the recycled DES maintained a superior delignification effect but significantly decreased pyrolysis efficiency compared to the fresh DES. This indicated that the highly condensed lignin with a large molecular weight is not favorable for producing phenolic compounds by pyrolysis. These highlight the potential of DES-based strategies for the efficient extraction and structural tailoring of lignin to maximize the production of value-added phenolic compounds.
The fabrication of porous materials possessing ultrahigh specific surface areas remains a significant challenge. We report the synthesis of two novel porous aromatic frameworks, PAF-336 and PAF-337, constructed from 6- and 8-connected building blocks with triangular prismatic and cuboid geometries, respectively. PAF-336 demonstrates an ultrahigh specific surface area (~5,210 m2·g-1) and large pore volume (3.5 cm3·g-1). This high porosity translates to high hydrogen storage capacity and state-of-the-art methane storage performance, positioning PAF-336 as a potential material for clean energy storage.
