Increasing the amount of active sites and enhancing their intrinsic activity are two basic strategies for designing electrocatalytic materials. [3,18] Nanostructured electrocatalytic materials have been extensively studied because of their high specific surface area. [6,9,10] Amorphous materials have also been widely explored in the field of electrocatalysis because of their specific structure and property. [19][20][21][22][23] In comparison with crystal materials, amorphous materials have the following characteristics. First, amorphous materials have long-range disorder and short-range order intrinsic structural characteristics and possess rich defects and active sites. [19][20][21][22][23][24][25] Second, the chemical composition of amorphous materials can be regulated in a wide range, [26] thereby fine tuning the electronic structure of catalysts. Third, amorphous materials possess isotropic property and can provide homogenous active sites during chemical reaction, [27] thereby favoring the regulation of reactant selectivity. Lastly, amorphous materials are usually prepared under mild conditions, which are conducive to the large-scale application of these materials. [28] Metal-organic frameworks (MOFs) are novel coordination compound materials with periodic and porous structures in which metal cations act as a coordination center and organic molecules serve as ligands. [29][30][31][32][33][34][35][36][37][38] Various MOF-derived materials, such as metal oxides, metal sulfides, and metal/carbon composites, have been prepared by heat treatment, hydrothermal/solvothermal treatment, or other treatment approaches for an MOF precursor. [39][40][41][42][43][44][45] The composition, morphological characteristics, and structure of MOF-derived materials can be effectively regulated. [39,40] MOF-derived materials can maintain the structural diversity and porosity characteristics of MOFs and effectively improve their conductivity and stability. [39,40] The structure and chemical property of MOF-derived materials can be regulated by MOF precursor design and treatment control. [39,40] Therefore, MOF-derived materials have good application prospects in electrochemical energy storage, electrochemical energy conversion, and electrochemical sensors. [46][47][48][49] As a typical representative of zeolitic imidazolate framework MOF material, ZIF-67 has been extensively studied as a precursor for derivative preparation. [50] Moreover, ZIF-67 derivatives have received more and more attentions in the field of electrocatalysis. [51][52][53][54][55][56] In the present study, an amorphous intermediate derivative was prepared using a ZIF-67 hollow sphere (HS-ZIF-67) as a precursor via low-temperature heat treatment Increasing active sites is an effective method to enhance the catalytic activity of catalysts. Amorphous materials have attracted considerable attention in catalysis because of their abundant catalytic active sites. Herein, a series of derivatives is prepared via the low-temperature heat treatment of ZIF-67 hollow sphere at ...

Hollow carbon-based materials derived from metal–organic frameworks for electrocatalysis and electrochemical energy storage are summarized and evaluated.

Developing high‐performance electrocatalysts for the ethanol oxidation reaction (EOR) and the oxygen reduction reaction (ORR) is essential for the commercialization of direct ethanol fuel cells, but it is still formidably challenging. In this work, a novel Pd–Sb hexagonal nanoplate for boosting both cathodic and anodic fuel cell reactions is prepared. Detailed characterizations reveal that the nanoplates have ordered rhombohedral phase of Pd8Sb3 (denoted as Pd8Sb3 HPs). The Pd8Sb3 HPs exhibit much enhanced activity toward the oxidation of various alcohols. Particularly, Pd8Sb3 HPs/C displays superior specific and mass activities of 29.3 mA cm−2 and 4.5 A mgPd−1 toward the EOR, which are 7.0 and 11.3 times higher than those of commercial Pd/C, and 9.8 and 3.8 times higher than those of commercial Pt/C, respectively, representing one of the best EOR catalysts reported to date. In situ electrochemical attenuated total reflectance surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) measurements reveal that Pd8Sb3 HPs/C can effectively promote the C2 pathway of the EOR. As revealed by density functional theory calculations, the high EOR activity of the Pd8Sb3 HPs can be ascribed to the reduced energy barrier of ethanol dehydrogenation. Additionally, Pd8Sb3 HPs/C also shows superior performance in the ORR. This work advances the controllable synthesis of the Pd–Sb nanostructure, giving huge impetus for the design of high‐efficiency electrocatalysts for energy conversion and beyond.

Breaking the bottleneck of hydrogen oxidation/evolution reactions (HOR/HER) in alkaline media is of tremendous importance for the development of anion exchange membrane fuel cells/water electrolyzers. Atomically dispersed active sites are known to exhibit excellent activity and selectivity toward diverse catalytic reactions. Here, a class of unique Rh2Sb nanocrystals with multiple nanobranches (denoted as Rh2Sb NBs) and atomically dispersed Rh sites are reported as promising electrocatalysts for alkaline HOR/HER. Rh2Sb NBs/C exhibits superior HER performance with a low overpotential and a small Tafel slope, outperforming both Rh NBs/C and commercial Pt/C. Significantly, Rh2Sb NBs show outstanding HOR performance of which the HOR specific activity and mass activity are about 9.9 and 10.1 times to those of Rh NBs/C, and about 4.2 and 3.7 times to those of Pt/C, respectively. Strikingly, Rh2Sb NBs can also exhibit excellent CO tolerance during HOR, whose activity can be largely maintained even at 100 ppm CO impurity. Density functional theory calculations reveal that the unsaturated Rh sites on Rh2Sb NBs surface are crucial for the enhanced alkaline HER and HOR activities. This work provides a unique catalyst design for efficient hydrogen electrocatalysis, which is critical for the development of alkaline fuel cells and beyond.

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