Solvated network of two-dimensional materials in the form of hydrogel offers a unique platform for full utilization of surface dominated properties at the macroscopic scale. However, development of such hydrogels...

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The assembly of MXene nanosheets into a hydrogel framework is key to their grand success in practical applications. However, the scalable realization of such stable structures is challenging and requires critically high dispersion concentration for gelation. Herein, a simple yet highly controllable approach for the development of 2D and 3D monolithic hydrogels of MXene via electro‐tunable ordered assembly is reported. Directional electrophoretic drag of MXene and their gelation by voltage‐controlled in situ released ions at the electrode interface gives rise to stable hydrogels with tunable sheet orientations. Nanosheets can be arranged in‐plane or out‐of‐plane depending on the parallel or radial field created by customized electrode assembly. Further, the gelation rate can be easily regulated by the applied potential to achieve self‐standing hydrogel films in a few tens of seconds. The 2D hydrogels display excellent supercapacitive performance of 395 F g−1 at 2 mV s−1 with high retention of 42% at 5000 mV s−1. In another customized application, the 3D‐monolithic MXene hydrogel displays outstanding performance as a solar‐thermal evaporator on behalf of its vertical sheet orientations, showing an excellent evaporation rate of 1.91 kg m−2 g−1. This simple, fast, scalable, and sheet orientation‐controlled assembly can pave the way for future development of MXene hydrogels and beyond.

The research on various bimetallic nanoparticles (NPs) is rapidly expanding due to their widespread applications. However, the formation of bimetallic nanostructures in a facile way remains challenging. In the present study, an octahedral (Oh) PdFe alloy nanostructure was designed by following an aqueous medium synthesis strategy. Different metal precursor ratios were varied to observe the change in the shape and distribution of the Oh PdFe alloy nanostructure. Surprisingly, increasing the Fe content directed the finer growth of Oh morphology. However, increasing the Pd amount resulted in an uneven Oh PdFe alloy shape. The catalytic activity of the optimized Oh PdFe alloy was examined for Hiyama cross-coupling, and the degradation of dyes was scrutinized at different pH. The suggested alloy nanostructured catalyst exhibited improved catalytic behavior compared to other nanocatalysts, such as commercial catalyst Pd/C (95%), monometallic Pd Oh (98%), Fe NPs (15%), and PdFe NPs (85%), for the Hiyama cross-coupling reaction. The optimized alloy catalyst with less Pd and more Fe demonstrated 98% yield and excellent reusability up to the fifth consecutive cycle, conveying 80% yield. The stability of the Oh PdFe alloy nanocatalyst and the mechanistic aspects of Hiyama cross-coupling was supported by density functional theory. The degradation of both anionic dyes, Congo red, Eosin Y, and cationic rhodamine B, was performed under normal along with acidic and basic conditions. The degradation reaction was completed in an adequate time interval for all the dyes with no change in the morphology of the synthesized catalyst.

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