Yang Li,Shouwei Zuo,Qiaohong Li,Huawei Huang,Xin Wu,Jing Zhang,Huabin Zhang,Jian Zhang
Hierarchical structures with a complex interior and a functional exterior are highly advantageous for energy-related electrocatalysis. Herein, a carbon-supported molybdenum carbide/sulfide heterostructure interior is covered with a defect-rich MoS 2 nanosheet exterior. The resulting hierarchical structure (C–MoCS x @MoS 2 ) is a promising nanoreactor for seawater splitting. X-ray absorption spectroscopy demonstrates that MoC and MoS 2 are chemically integrated into the C–MoCS x core, providing abundant C–Mo–S sites for hydrogen evolution. Experimental studies and theoretical calculations show that the defect-rich MoS 2 exterior exhibits a high capability for repelling salt deposition, allowing the penetration of low-saline water into the inner C–MoCS x to accelerate the water-splitting reaction. As expected, the obtained C–MoCS x @MoS 2 is remarkably active and exceptionally stable in natural seawater. This work opens new avenues for developing effective electrocatalysts for seawater splitting and other energy-related applications.
A novel and practical CaCl 2 salt templating method is used to tune the pore size of carbon materials from calcium lignosulfonate. In-situ crystalized CaCl 2 particles serve as templates for mesopores and as carbonization substrates. Hierarchical carbons are constructed using coupled SiO 2 spheres and CaCl 2 templates. The SiO 2 spheres improve the pore size assigned to CaCl 2 particles and high CaCl 2 :lignin mass ratios benefit large CaCl 2 crystals to improve the size of mesopores. The porous carbons are used as supports of molybdenum carbide (MoC) with C-C and C-O cleavage activity for Kraft lignin decomposition into aromatic monomers. The results show that MoC over porous carbon supports achieves the highest aromatic yield of 0.716 g/g Kraft lignin and exhibits high stability of aromatic yields. Suitable pore size for lignin macromolecule diffusion significantly enhances the catalytic performance of molybdenum carbide.
A sensitive electrochemical sensor decorated with multiwalled carbon nanotubes and molybdenum carbide (MWCNTs-MoxCy) was successfully developed in this study for the simultaneous detection of hydroquinone (HQ) and o-hydroxyaniline (OHX). The MWCNTs-MoxCy nanomaterials were synthesized by high temperature calcination under nitrogen protection, and the morphologies and elements were characterized and analyzed using a scanning electron microscope (SEM) and energy dispersive spectrometry (EDS), respectively. The MWCNTs-MoxCy composite was ultrasonically dispersed into a modification liquid to construct the modified the glassy carbon electrode, and cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronocoulometry (CC) were used to study the electrochemical performance. In phosphate buffer solution, the synthetic materials displays good redox peaks for hydroquinone (HQ) and o-hydroxyaniline (OHX). The synthesized composite has a large effective surface area, high electron transfer rate and catalytic activity. Under optimum experimental conditions, the MWCNTs-MoxCy/GCE exhibits linear responses to HQ and OHX in the range of 0.1-900.0 μM and 0.8-20.0 μM, respectively, with a limit of determination (S/N=3) calculated to be 0.075 μM and 0.047 μM, respectively. The method was applied to measure the concentrations of these compounds in real water samples and achieved satisfactory results.
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