The photocatalytic conversion of biomass into valuable chemicals offers a more energy-efficient and low-carbon alternative to traditional thermal catalysis, representing a promising strategy for fine chemical production without relying on fossil fuels. While most studies have focused on catalyst design to improve efficiency, the precise tuning of solvents has been neglected. This study examines the conversion of 5-hydroxymethylfurfural (HMF) into 2,5-diformylfuran (DFF) as a representative biomass alcohol oxidation reaction, revealing a novel strategy for enhancing photocatalytic efficiency through solvent fine-tuning. The introduction of minute quantities of water into an acetonitrile solvent matrix during the HMF oxidation reaction was observed to engender pronounced enhancements in catalytic performance, with the degree of effect contingent on precise water concentration. Trace water is an active participant in the catalytic cycle, diminishing the activation energy barrier for bond cleavage and averting catalyst deactivation. This mechanism also proved applicable to other photocatalysts and various alcohol substrates, highlighting the potential of this strategy for enhancing photoenergy utilization and reaction efficiency.
Jiahang Zou,Hanxu Yang,Shilin Wu,Zhengquan Xiao,Zhipeng Jiang,Wangqiang Shen,Yongtao Li
Ether-based electrolytes are known for their high stability with lithium metal anodes (LMAs), but they often exhibit poor high-voltage stability. Structural optimization of ether-based solvent molecules has been proven to effectively broaden the electrochemical window of these electrolytes, yet the optimization rules within cyclic ethers remain unclear. Herein, we investigate the impact of methyl substitution positions on the molecular properties of 1,3-dioxolane (DOL), a commonly used cyclic ether. The results show that the introduction of methyl groups can effectively inhibit the ring-opening polymerization of DOL. Besides, 4-methyl-1,3-dioxolane (4-Me DOL), with larger steric hindrance compared to 2-methyl-1,3-dioxolane (2-Me DOL), exhibits weaker solvation ability, favoring the formation of anion-rich inner solvation sheath layers and anion-derived interfaces. Even at conventional concentrations, 1 M LiFSI in 4-Me DOL (LiFSI/4-Me DOL) electrolyte demonstrates good LMA stability and an expanded electrochemical window up to 4.6 V. The Li-LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cell using LiFSI/4-Me DOL could stably cycle over 300 times. This work reveals a new design principle for solvent molecules.
Yuchen Zhu,Hao Wu,Zheng Fang,Xiaobing Yang,Kai Guo,Wei He
Cobalt (II)-meso-tetra(4-carboxyphenyl) porphyrin supported by deprotected lignin was synthesized through the covalent linkage between carboxy groups in the porphyrin and hydroxyl groups in the lignin. The resulting supporting catalysts were applied in the selective oxidation of 5-hydroxymethylfurfural. Through solvent optimization, 5-hydroxymethyl-2-furancarboxylic acid and 2,5-furandicarboxylic acid could be selectively obtained. Steric effect of lignin prevented unwanted aggregation-caused quenching, avoiding catalyst deactivation. Thus, supported catalysts displayed better catalytic efficiency compared free metal porphyrin catalyst. Unlike the excessive use of sodium hydroxide in the oxidation of HMF catalyzed by metal catalysts, an equivalent amount of sodium hydroxide was used in this oxidation process. Meanwhile, lower activation energy was detected when metal porphyrin supported by deprotected lignin was used. By adjusting the pH in the reaction, supported catalysts could be reused. The catalytic activity remained stable during the recycling experiments.
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