2D High‐Entropy Hydrotalcites

Abstract

High‐entropy materials (HEMs) with unique configuration and physicochemical properties have attracted intensive research interest. However, 2D HEMs have not been reported yet. To find out unique properties of combining 2D materials and HEMs, a series of 2D high‐entropy hydrotalcites (HEHs) is created by coprecipitation method, including quinary, septenary, and even novenary metallic elements. It is found that the fast synthetic kinetics of coprecipitation process conquers the thermodynamically solubility limitation of different elements, which is the prerequisite condition to form HEHs. As the oxygen evolution reaction (OER) electrocatalysts, HEHs show significantly decreased apparent activation energy compared with low‐entropy hydrotalcites (LEHs) due to the lattice distortion induced by the multimetallic character of HEHs. This work opens up a new avenue for the development of 2D HEMs, which broadens the family of HEMs and presents a most promising platform for exploring the unknown properties of HEMs.

Two-Dimensional High-Entropy Metal Phosphorus Trichalcogenides for Enhanced Hydrogen Evolution Reaction

“…The pre-exponential factor ( A app ) and activation energy ( E app ) were calculated by the Arrhenius equation around the onset potential of the respective samples (Figure S14, Supporting Information). Compared with CoPS 3 NSs, the maxima of both A app and E app were observed around a lower η in Co 0.6 (VMnNiZn) 0.4 PS 3 NSs (Figures f and S15, Supporting Information) . The higher A app suggests that the catalytic active sites in Co 0.6 (VMnNiZn) 0.4 PS 3 NSs are enhanced by modifying the entropy of activation, which allows more active sites to participate in the HER process, as the predominance on the HER kinetics significantly influences the reaction rate.…”

“…Compared with CoPS 3 NSs, the maxima of both A app and E app were observed around a lower η in Co 0.6 (VMnNiZn) 0.4 PS 3 NSs (Figures 4f and S15, Supporting Information). 56 The higher A app suggests that the catalytic active sites in Co 0.6 (VMnNiZn) 0.4 PS 3 NSs are enhanced by modifying the entropy of activation, which allows more active sites to participate in the HER process, as the predominance on the HER kinetics significantly influences the reaction rate. Meanwhile, the increased reaction entropy needs a higher E app as reaction enthalpy to compensate for the change in binding energy, due to the stable enthalpy−entropy compensation effect in alkaline pH condition at both normal and high temperatures (Figure S12, Supporting Information).…”

High‐Entropy Catalyst—A Novel Platform for Electrochemical Water Splitting

“…[12,14,15] The remarkably declined apparent activation energy of LiMo-FeCoNi high-entropy hydrotalcite (HEH) due to the lattice distortion was analyzed in the work of Figure 12b and extremely boosted catalytic performance (187 mV @10 mA•cm −2 ). [188] Zhang thoroughly investigated a tunable coordination environment for the enhancement of OER performance for highentropy MOF-based (HEMOF) electrocatalysts. As pictured in Figure 12c, introducing multi-component metallic sites at random in MOFs can form an unsaturated coordination environment due to partial lattice distortion.…”

Emerging Graphene Derivatives and Analogues for Efficient Energy Electrocatalysis

“…[243,244] Recently, the strategy of designing HE materials was also introduced in the research of metal-based graphene analogues to improve the electrocatalytic activity. [245][246][247][248][249][250][251] Gu et al synthesized HE layered double hydroxides (LDHs) by hydrothermal method and then exfoliated them to ultrathin defective LDH nanosheets by plasma treating (Figure 8a). [247] Metal elements were highly dispersed with uniform atomic distribution in the ultrathin defective HE-LDHs, and the Fe-Cr-Co-Ni-Cu HE-LDHs exhibited excellent OER performance with a low overpotential and fast kinetics.…”