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Metal selenides, such as NiSe2, have exhibited great potentials as multifunctional materials for energy storage and conversation. However, the utilization of pure NiSe2 as electrode materials is limited by its poor cycling stability, low electrical conductivity, and insufficient electrochemically active sites. To remedy these defects, herein, a novel NiSe2/Ti3C2Tx hybrid with strong interfacial interaction and electrical properties is fabricated, by wrapping NiSe2 octahedral crystal with ultrathin Ti3C2Tx MXene nanosheet. The NiSe2/Ti3C2Tx hybrid exhibits excellent electrochemical performance, with a high specific capacitance of 531.2 F g−1 at 1 A g−1 for supercapacitor, low overpotential of 200 mV at 10 mA g−1, and small Tafel slope of 37.7 mV dec−1 for hydrogen evolution reaction (HER). Furthermore, greater cycling stabilities for NiSe2/Ti3C2Tx hybrid in both supercapacitor and HER have also been achieved. These significant improvements compared with unmodified NiSe2 should be owing to the strong interfacial interaction between NiSe2 octahedral crystal and Ti3C2Tx MXene, which provides enhanced conductivity, fast charge transfer as well as abundant active sites, and highlight the promising potentials in combinations of MXene with metal selenides for multifunctional applications such as energy storage and conversion.

In this work, we presented a novel route to synthesize boron doped reduced graphene oxide (rGO) by using the dielectric barrier discharge (DBD) plasma technology under ambient conditions. The doping of boron (1.4 at%) led to a significant improvement in the capacitance of rGO and supercapacitors based on the as-synthesized B-rGO exhibited an outstanding specific capacitance.

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Droplet formation in a wide-type microfluidic T-junction was studied using the computational fluid dynamics (CFD) method. Two distinct regimes of droplet formation were confirmed: dripping and jetting; and, at both regimes, droplet size decreases with an increase in capillary number. CFD simulation demonstrated that droplet formation in the T-junction can be divided into three steps: droplet emergence and growing up; separation with the disperse phase; and detachment from the channel wall. The wettability of the channel wall significantly affects the process of droplet detachment from the channel wall; also, the simulation clearly showed that droplets can be formed only when the continuous phase fluid preferentially wets the channel wall, that is, its contact angle on the wall is smaller than 90 . Finally, the CFD study verified that the disperse phase flow rate can significantly affect the droplet size as well as the mechanism of droplet formation.

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Scheme1.a) Redoxreaction triggered by hydroquinone/quinone moieties. b) Evolution of the functional groupsi nKLu pon oxidation treatment.[a] Dr.

Ti3C2T x MXene is one of the most promising electrode materials for supercapacitors, but it often suffers in poor experiment gravimetric capacitance, which limits practical applications in industry needs. Herein, etched Ti3C2T x MXene with high gravimetric capacitance is prepared by chemical etching of MXene with concentrated alkaline solution. The intercalation of K+ and the scissor role of OH− can simultaneously enlarge the interlayer spacing and cut the size of sheets, which lead to the high active‐site concentration and cation diffusion. As a result, the etched Ti3C2T x MXene displays high gravimetric capacitance of 368.1 F g−1 at 2 A g−1 and outstanding cycling stability without capacitance loss over 5000 cycles at 6 A g−1,and the surface capacitance contribution in etched Ti3C2T x MXene occurs to a greater extent compared with the pristine MXene. Moreover, the effect of chemical etching on the supercapacitor performance and energy‐storage mechanism indicates that the active‐size concentration and cation diffusion could be maximized when the chemical etching conditions are appropriate, leading to the highest performance of etched Ti3C2T x MXene. Herein, it is demonstrated that the chemical etching approach is applicable to design MXenes with high gravimetric capacitance to maximize their potential applications in energy‐storage applications and other fields.