RESUMEN
Alcohol electrooxidation is pivotal for a sustainable energy economy. However, designing efficient electrocatalysts for this process is still a formidable challenge. Herein, palladium-selenium nanowires featuring distinct crystal phases: monoclinic Pd7Se2 and tetragonal Pd4.5Se for ethylene glycol electrooxidation reaction (EGOR) are synthesized. Notably, the supported monoclinic Pd7Se2 nanowires (m-Pd7Se2 NWs/C) exhibit superior EGOR activity, achieving a mass activity (MA) and specific activity (SA) of 10.4 A mgPd -1 (18.7 mA cm-2), which are 8.0 (6.7) and 10.4 (8.2) times versus the tetragonal Pd4.5Se and commercial Pd/C and surpass those reported in the literature. Furthermore, m-Pd7Se2 NWs/C displays robust catalytic activity for other alcohol electrooxidation. Comprehensive characterization and density functional theory (DFT) calculations reveal that the enhanced electrocatalytic performance is attributed to the increased formation of Pd0 on the high-index facets of the m-Pd7Se2 NWs, which lowers the energy barriers for the CâC bond dissociation in CHOHCHOH* and the CO* oxidation to CO2*. This study provides palladium-based alloy electrocatalysts exhibiting the highest mass activity reported to date for the electrooxidation of ethylene glycol, achieved through the crystalline phase engineering strategy.
RESUMEN
Graphitic-carbon nitride (g-C3N4), a metal-free two-dimensional layered semiconductor material, holds great potential for energy conversion, environmental remediation, and sensing. However, the limited solubility of g-C3N4 in conventional solvents hinders its widespread application. Improving the dissolution of g-C3N4 in the liquid phase is highly desired but challenging. Herein, we report an innovative approach to dissolve g-C3N4 using ZnCl2 molten salt hydrates. The solubility of g-C3N4 in the solution reaches up to 200 mg mL-1. Density functional theory (DFT) results suggest that ZnCl+H2O is the key species that leads to charge redistribution on g-C3N4 surface and promotes the dissolution of carbon nitride in the solution. Furthermore, through dilution, the dissolved carbon nitride can be effectively recovered while maintaining its intrinsic chemical structure. The resultant regenerated C3N4 (r-C3N4) exhibits nanobelt morphology and demonstrates a substantially improved photocatalytic activity in H2O2 production. The rate of H2O2 production over the r- C3N4 reaches 20,228 µmol g-1 h-1, which is 6.2 times higher than that of pristine g-C3N4. This green and efficient dissolution route of g-C3N4 offers an effective approach for its diverse applications.
RESUMEN
In this work, we propose a novel and facile route for the rational design of Si@SiO2/C anode materials by using sustainable and environment-friendly cellulose as a carbon resource. To simultaneously obtain a SiO2 layer and a carbon scaffold, a specially designed homogeneous cellulose solution and commercial Si nanopowder are used as the starting materials, and the cellulose/Si composite is directly assembled by an in situ regenerating method. Subsequently, Si@SiO2/C composite is obtained after carbonization. As expected, Si@SiO2 is homogeneously encapsulated in the cellulose-derived carbon network. The obtained Si@SiO2/C composite shows a high reversible capacity of 1071 mA h g-1 at a current density of 420 mA g-1 and 70% capacity retention after 200 cycles. This novel, sustainable, and effective design is a promising approach to obtain high-performance and cost-effective composite anodes for practical applications.