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Molybdenum disulfide (MoS2) is intrinsically inert for the hydrogen evolution reaction (HER) in alkaline media due to its electronic structures. Herein, we tune the electronic structures of MoS2 by a combined strategy of post-N doping coupled with the synergistic effect of Ti3C2TX. The as-prepared N-doped MoS2/Ti3C2TX heterostructures show remarkable alkaline HER activity with an overpotential of 225 mV at 140 mA cm-2, which ranks the N-doped MoS2/Ti3C2TX heterostructures among the best MoS2/MXene-based electrocatalysts reported for alkaline HER. The first-principles calculations indicate that the N doping can enhance the activation of nearby S sites of MoS2/Ti3C2TX and thus promote the HER process. This strategy provides a promising way to develop high-efficiency MoS2/MXene heterostructure catalysts for alkaline HER.

Unusual three-dimensional mesoporous carbon/reduced graphene oxide (MP-C/rGO) matrix possessing graphene nanolayer pore walls built up by three to five graphene monosheets and some carbon particles with the sizes of about 5 nm located between the graphene nanolayers was prepared by facile freeze-drying and then carbonization of the poly(vinyl alcohol) and graphene oxide mixture. The mesoporous carbonaceous MP-C/rGO sample has a high specific surface area of 661.6 m2 g-1, large specific pore volume of 1.54 m3 g-1, and focused pore size distribution of 2-10 nm. About 64 wt % sulfur could be held in the pores of the MP-C/rGO matrix. As the cathode of a Li-S battery, the MP-C/rGO/S composite showed excellent electrochemical property including a high initial specific capacity of 919 mA h g-1 at 1 C with the capacity retention ratio of 63.3% and the Coulombic efficiency above 90% after 500 cycles. Meanwhile, the initial specific capacity of 602 mA h g-1 at 5 C and remaining capacity of 391 mA h g-1 after 500 cycles with an outstanding Coulombic efficiency of 97% indicate its exceptionally stable rate performance.

The rapid development of cellulosic bioethanol has produced a mass of hydrolysate residue as byproducts during the pretreatment process of lignocellulose. The high value-added utilization of hydrolysate residue plays a key role in the economic viability of large-scale/green industrial production of lignocellulose into bioethanol. Here the hydrolyzate residue was exploited as a carbon precursor for the fabrication of an interlinked graphitized porous carbon nanoflake (GPCNF) by an in situ carbonization–activation process. The final GPCNF presents an optimum integration of a large surface area of 2026 m2 g–1, bimodal pore systems (86% of mesopore volume), and an excellent electric conductivity of 5.4 S cm–1. These characteristics favorably endow that the GPCNF is ideally suited for nonaqueous electrolyte-based supercapacitor applications. In organic electrolyte of 1 M TEA BF4/AN, the GPCNF-based supercapacitor exhibits a high rate capability of 74% initial capacitance at a high current density of 100 A g–1....