High‐entropy alloys (HEAs) have attracted widespread attention in electrocatalysis due to their unique advantages (adjustable composition, complex surface, high tolerance, etc.). They allow for the formation of new and tailorable active sites in multiple elements adjacent to each other, and the interaction can be tailored by rational selection of element configuration and composition. However, it needs to be further explored in catalyst design, the interaction of elements, and the determination of active sites. This review article focuses on the important progress for multi‐sites electrocatalysis in HEAs. The classification is done on the basis of catalytic reaction, including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, alcohol oxidation reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction. Based on experiments and theories, a more in‐depth exploration of the high catalytic activity of HEAs will be conducted, including the selection of elements (the special role of each element in catalysis) and the multi‐sites effect. This review can provide the basis for the element selection and design of HEAs in some reactions, to adjust the compositions of HEAs to improve their intrinsic activity. Furthermore, the remaining challenges and future directions for promising research fields are also provided.

Interlayer engineering – simultaneous structure and surface chemistry modification can help Ti3C2Tx MXenes achieve the theoretical capacitance.

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Direct ethanol fuel cells are among the most efficient and environmentally friendly energy-conversion devices and have been widely focused. The ethanol oxidation reaction (EOR) is a multielectron process with slow kinetics. The large amount of by-product generated by incomplete oxidation greatly reduces the efficiency of energy conversion through the EOR. In this study, a novel type of trimetallene called porous PdWM (M = Nb, Mo and Ta) is synthesized by a facile method. The mass activity (15.6 A mg Pd −1 ) and C1 selectivity (55.5%) of Pd 50 W 27 Nb 23 /C trimetallene, obtained after optimizing the compositions and proportions of porous PdWM, outperform those of commercial Pt/C (1.3 A mg Pt −1 , 5.9%), Pd/C (5.0 A mg Pd −1 , 7.2%), and Pd 97 W 3 /C bimetallene (9.5 A mg Pd −1 , 14.1%). The mechanism by which Pd 50 W 27 Nb 23 /C enhances the EOR performance is evaluated by in situ Fourier transform infrared spectroscopy and density functional theory calculations. It is found that W and Nb enhance the adsorption of CH 3 CH 2 OH and oxophilic high-valence Nb accelerates the subsequent oxidation of CO and -CH x species. Moreover, Nb promotes the cleavage of C-C bonds and increases the C1 selectivity. Pd 60 W 28 Mo 12 /C and Pd 64 W 27 Ta 9 /C trimetallene synthesized by the same method also exhibit excellent EOR performance.

g-C3N4 with a layered structure has been proven as an outstanding metal-free organic photocatalyst because of its appropriate bandgap, abundant building elements, and excellent chemical stability. Here, a simple one-step ball milling method is presented for synthesis of mechanically exfoliated g-C3N4 (MECN) thin nanosheets at large scales for the first time. Characterization results showed that gradual size reduction, accompanied by continual bandgap absorption shift, occurred with increasing grinding time. The obtained MECN thin nanosheets showed significantly enhanced simulated sun light driven photocatalytic activity toward organic degradation compared to their bulk counterpart, highlighting the crucial role of morphology and surface area on the photocatalytic performance.

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Restricted rate capability is the key bottleneck for the large‐scale energy storage of battery‐type supercapacitor cathode due to its sluggish reaction kinetics. Herein, Ni(Co)Se2@Co(Ni)Se2 semicoherent heterojunctions with rich Se vacancies (Vr‐Ni(Co)Se2@Co(Ni)Se2) as cathode are first constructed. Such a vacancy and heterointerface manipulation can not only essentially regulate the electronic structure and enhance ions adsorption capability, but also rationalize the chemical affinities of OH– ions in diffusion pathway revealed by systematic characterization analysis and first‐principle calculations. The as‐prepared cathode delivers large specific capacity of 264.5 mAh g–1 at 1 A g–1 and excellent cycle stability. Surprisingly, it presents ultrahigh rate with the retention of 159.7 mAh g–1 even at 250 A g–1. Moreover, the single phase transition mechanism of the cathode is elucidated systematically using series of ex situ techniques. In addition, contributed by the unique cathode and the self‐synthesized N/S co‐doped corncob‐derived porous carbon (N/S‐BPC, 316.1 F g–1 at 1 A g–1) anode, a high‐performance hybrid supercapacitor (HSC) is developed, which shows the energy density of 68.1 Wh kg–1 at 0.75 kW kg–1 and a superior cycle performance. The findings highlight a coordination strategy for the rational design of ultrahigh‐rate battery‐type HSC cathode, greatly pushing their commercial application processes.