Noble metals manifest themselves with unique electronic structures and irreplaceable activity toward a wide range of catalytic applications but are unfortunately restricted by limited choice of geometric structures spanning single atoms, clusters, nanoparticles, and bulk crystals. Herein, we propose how to overcome this limitation by integrating noble metal atoms into the lattice of transition metal oxides to create a new type of hybrid structure. This study shows that iridium single atoms can be accommodated into the cationic sites of cobalt spinel oxide with short-range order and an identical spatial correlation as the host lattice. The resultant Ir0.06Co2.94O4 catalyst exhibits much higher electrocatalytic activity than the parent oxide by 2 orders of magnitude toward the challenging oxygen evolution reaction under acidic conditions. Because of the strong interaction between iridium and cobalt oxide support, the Ir0.06Co2.94O4 catalyst shows significantly improved corrosion resistance under acidic conditions and oxidative potentials. This work eliminates the “close-packing” limitation of noble metals and offers promising opportunity to create analogues with desired topologies for various catalytic applications.

Electron microscopy allows the extraction of multidimensional spatiotemporally correlated structural information of diverse materials down to atomic resolution, which is essential for figuring out their structureproperty relationships. Unfortunately, the high-energy electrons that carry this important information can cause damage by modulating the structures of the materials. This has become a significant problem concerning the recent boost in materials science applications of a wide range of beam-sensitive materials, including metal-organic frameworks, covalent-organic frameworks, organicinorganic hybrid materials, 2D materials, and zeolites. To this end, developing electron microscopy techniques that minimize the electron beam damage for the extraction of intrinsic structural information turns out to be a compelling but challenging need. This article provides a comprehensive review on the revolutionary strategies toward the electron microscopic imaging of beamsensitive materials and associated materials science discoveries, based on the principles of electron-matter interaction and mechanisms of electron beam damage. Finally, perspectives and future trends in this field are put forward. he worked as a postdoctoral fellow and research scientist at King Abdullah University of Science and Technology. His research interests now focus on low-dose electron microscopy and structural elucidation of beam-sensitive materials for applications such as catalysis, gas separation, and energy conversion/storage.

Integrated differential phase‐contrast scanning transmission electron microscopy (iDPC‐STEM) is capable of directly probing guest molecules in zeolites, owing to its sufficient and interpretable image contrast for both heavy and light elements under low‐dose conditions. This unique ability is demonstrated by imaging volatile organic compounds adsorbed in zeolite Silicalite‐1; iDPC‐STEM was then used to investigate molybdenum supported on various zeolites including Silicalite‐1, ZSM‐5, and mordenite. Isolated single‐Mo clusters were observed in the micropores of ZSM‐5, demonstrating the crucial role of framework Al in driving Mo atomically dispersed into the micropores. Importantly, the specific one‐to‐one Mo‐Al interaction makes it possible to locate Al atoms, that is, catalytic active sites, in the ZSM‐5 framework from the images, according to the positions of Mo atoms in the micropores.

The application of electrochemical energy storage materials to capacitive deionization (CDI), a low‐cost and energy‐efficient technology for brackish water desalination, has recently been proven effective in solving problems of traditional CDI electrodes, i.e., low desalination capacity and incompatibility in high salinity water. However, Faradaic electrode materials suffer from slow salt removal rate and short lifetime, which restrict their practical usage. Herein, a simple strategy is demonstrated for a novel tubular‐structured electrode, i.e., polyaniline (PANI)‐tube‐decorated with Prussian blue (PB) nanocrystals (PB/PANI composite). This composite successfully combines characteristics of two traditional Faradaic materials, and achieves high performance for CDI. Benefiting from unique structure and rationally designed composition, the obtained PB/PANI exhibits superior performance with a large desalination capacity (133.3 mg g−1 at 100 mA g−1), and ultrahigh salt‐removal rate (0.49 mg g−1 s−1 at 2 A g−1). The synergistic effect, interfacial enhancement, and desalination mechanism of PB/PANI are also revealed through in situ characterization and theoretical calculations. Particularly, a concept for recovery of the energy applied to CDI process is demonstrated. This work provides a facile strategy for design of PB‐based composites, which motivates the development of advanced materials toward high‐performance CDI applications.

Creating molecular networks with different topologies using identical molecular linkers is fundamentally important, but requires a precise chemistry control. Here, we propose an effective strategy to regulate network topologies of two-dimensional (2D) covalent organic frameworks (COFs) through conformation switching of molecular linkages. By simply altering the substituents of an identical molecular linker, the topology-selective synthesis of two highly crystalline 2D COFs can be readily achieved. Their distinct crystal structures are observed and determined by low-dose high-resolution transmission electron microscopy imaging, indicating that the driving force for linkage conformation switching is intramolecular hydrogen bonding. Our strategy would greatly diversify the COF topologies and enable vast post-synthetic modifications like boron complexation, endowing these structures with unique optical property, such as fluorescence "turn on" and "aggregation-induced emission".

Metal/oxide interface is of fundamental significance to heterogeneous catalysis because the seemingly “inert” oxide support can modulate the morphology, atomic and electronic structures of the metal catalyst through the interface. The interfacial effects are well studied over a bulk oxide support but remain elusive for nanometer-sized systems like clusters, arising from the challenges associated with chemical synthesis and structural elucidation of such hybrid clusters. We hereby demonstrate the essential catalytic roles of a nanometer metal/oxide interface constructed by a hybrid Pd/Bi2O3 cluster ensemble, which is fabricated by a facile stepwise photochemical method. The Pd/Bi2O3 cluster, of which the hybrid structure is elucidated by combined electron microscopy and microanalysis, features a small Pd-Pd coordination number and more importantly a Pd-Bi spatial correlation ascribed to the heterografting between Pd and Bi terminated Bi2O3 clusters. The intra-cluster electron transfer towards Pd across the as-formed nanometer metal/oxide interface significantly weakens the ethylene adsorption without compromising the hydrogen activation. As a result, a 91% selectivity of ethylene and 90% conversion of acetylene can be achieved in a front-end hydrogenation process with a temperature as low as 44 °C.

The 3d‐transition‐metal (hydro)oxides belong to a group of highly efficient, scalable and inexpensive electrocatalysts for widespread energy‐related applications that feature easily tailorable crystal and electronic structures. We propose a general strategy to further boost their electrocatalytic activities by introducing organic ligands into the framework, considering that most 3d‐metal (hydro)oxides usually exhibit quite strong binding with reaction intermediates and thus compromised activity due to the scaling relations. Involving weakly bonded ligands downshifts the d‐band center, which narrows the band gap, and optimizes the adsorption of these intermediates. For example, the activity of the oxygen evolution reaction (OER) can be greatly promoted by ≈5.7 times over a NiCo layered double hydroxide (LDH) after a terephthalic acid (TPA)‐induced conversion process, arising from the reduced energy barrier of the deprotonation of OH* to O*. Impressively, the proposed ligand‐induced conversion strategy is applicable to a series of 3d‐block metal (hydro)oxides, including NiFe2O4, NiCo2O4, and NiZn LDH, providing a general structural upgrading scheme for existing high‐performance electrocatalytic systems.

Noble metals have broad prospects for catalytic applications yet are restricted to a few packing modes with limited structural flexibility. Here, we achieved geometric structure diversification of noble metals by integrating spatially correlated noble metal single atoms (e.g., Pt, Pd, and Ru) into the lattice of transition metal oxides (TMOs, e.g., Co 3 O 4 , Mn 5 O 8 , NiO, Fe 2 O 3 ). The obtained noble metal single atoms exhibited distinct topologies (e.g., crs, fcu-hex-pcu, fcu, and bcu-x) from those of conventional metallic phases. For example, Pt single atoms with a crs topology (Pt crs -Co 3 O 4 ) are endowed with synergy of metal−metal and metal−support interactions. A quantitative relationship between various Pt topologies determined by TMO substrates and their electrocatalytic activities was established. We anticipate that this type of interactive singleatom catalysts can bridge the geometric, topological, and electronic structure gaps between the "close-packed" nanoparticles and isolated single atoms as two common categories of heterogeneous catalysts.