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An optical sensor array based on chemiluminescent images from spots of nanomaterials has been employed to recognize odorous samples. The distinctive images obtained from the array permit identification of a wide range of analytes, even homologous compounds.

The recent dramatic increase in research on isolated metal atoms has received extensive scientific interest in the new frontier of single‐atom catalysis. As newly advanced materials in catalysis, single‐atom catalysts (SACs) have received enormous interest from the perspectives of both scientific research and industrial applications due to their remarkable activity. In addition, other catalytic properties of single metal atoms, including stability and selectivity, can be further improved by tuning their electronic/geometric structures and modulating the metal–support interactions. SACs usually consist of dispersed atoms and appropriate support materials, which are employed to anchor, confine, and/or coordinate with isolated metal atoms. Therefore, the nature of single metal sites allows acquiring a maximum atom utilization approaching 100%, which is of significance, particularly for the development of noble‐metal‐based catalysts. In order to systematically understand the structure–property relationships and the underlying catalytic mechanisms relationship of SACs, the representative scientific research efforts in their synthesis strategies, catalytic applications, and performance regulation are discussed here. Typical single‐atom catalysis processes and the corresponding mechanisms in electrochemistry, photochemistry, organic synthesis, and biomedicine are also summarized. Finally, the challenges and prospects for the development of single‐atom catalysis and SACs are highlighted.

Self-standing single crystalline NiCo2S4 hollow nanorod arrays are prepared for catalysing the polysulfide redox couple in quantum dot-sensitized solar cells (QDSCs). The QDSCs using NiCo2S4 as a counter electrode (CE) achieved a power conversion efficiency of 4.22%, which exceeds the performance of QDSCs based on a Pt CE by 38.4%.

Fiber-based multifunctional nickel phosphide electrodes have been successfully prepared by facile electrodeposition of nickel nanoparticle arrays on a commercial carbon fiber followed by low-temperature phosphidation. With the synergistic effect from the hierarchically porous structure and chemical compositions, the resultant electrodes exhibit excellent performance for overall water-splitting electrocatalysis and flexible supercapacitors.

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TMDCs, [7][8][9] the quantum spin Hall effect, [10] the valleytronics, [11,12] as well as the 2D superconductivity, [13] implying extensive potential applications. In contrast to graphene, monolayer TMDCs with suitable bandgaps have demonstrated the state-of-the-art characteristics for integrated circuits (IC), i.e., high on/ off ratio (>10 7 ) and record drive current density (100 µA µm −1 ). [14,15] So far, a number of approaches have been developed to obtain TMDCs, including the micromechanical cleavage method [16] and liquid-phase exfoliation [17][18][19] due to the weak van der Waals interactions between the neighboring layers. Among them, chemical vapor deposition (CVD) has been widely demonstrated to be an effective technique to synthesize highquality TMDCs as well as their in-plane and vertical heterostructures by using different precursors, [20,21] such as the solid powders of MoO 3 , [22][23][24][25] MoO 3 solution, [26,27] MoCl 5 , [28] WO 3 , [29,30] WS 2 , WSe 2 , MoS 2 , and MoSe 2 [31][32][33] with the additional alkali metal halides as the growth promoters, [2,34] the gaseous chemical precursors including molybdenum hexacarbonyl (MHC), [4] as well as the liquid precursors like the solution of ammonium thiomolybdate (NH 4 ) 2 MoS 4 , [35,36] ammonium molybdate tetrahydrate (NH 4 ) 6 Mo 7 O 24 •4H 2 O and ammonium tungstate hydrate Chemical vapor deposition (CVD) has been widely used to synthesize highquality 2D transition-metal dichalcogenides (TMDCs) from different precursors. At present, quantitative control of the precursor with high precision and good repeatability is still challenging. Moreover, the process to synthesize TMDCs with designed patterns is complicated. Here, by using an industrial inkjet-printer, an in situ aqueous precursor with robust usage control at the picogram (10 −12 g) level is achieved, and by precisely tuning the inkjetprinting parameters, followed by a rapid heating process, large-area patterned TMDC films with centimeter size and good thickness controllability, as well as heterostructures of the TMDCs, are achieved facilely, and high-quality single-domain monolayer TMDCs with millimeter-size can be easily synthesized within 30 s (corresponding to a growth rate up to 36.4 µm s −1 ). The resulting monolayer MoS 2 and MoSe 2 exhibits excellent electronic properties with carrier mobility up to 21 and 54 cm 2 V −1 s −1 , respectively. The study paves a simple and robust way for the in situ ultrafast and patterned growth of high-quality TMDCs and heterostructures with promising industrialization prospects. Moreover, this ultrafast and green method can be easily used for synthesis of other 2D materials with slight modification.

The use of reactive oxygen species (ROS) generators based on singleatom catalysts (SACs) has been an emerging strategy for mediating tumor therapy, however, the current systems suffer from low mass transport efficiency. Here, a novel strategy of morphology fragmentation is developed to fabricate flower-like SAC nanozymes with greatly improved 3D accessibility of active sites. Specifically, the coordinationally polymerized zeolite imidazole framework acts as a polyphenol oxidase-like enzyme to catalyze the in situ polymerization of polydopamine (PDA) which leads to blockage of micropores and crosslinking of the morphologydeteriorated ZIF nanosheets. The protective carbonization by PDA results in SAC nanozymes (C-NFs) with plenty of reopened micropores and defect mesopores (≈4 nm) in the nanopetals, large interpetal pore space (≈39 nm), high surface area (388 m 2 g −1 ), as well as an ultrahigh loading metal atoms (27.3 wt%). Subsequently, a superior peroxidases-like activity (36.6-fold increment in the turnover frequency) facilitates significantly strengthened ROS generation and damage of biomolecules. Moreover, the employment of apoferritin modification/loading leads to particle dispersion in solution and concomitant drug loading. The following cancer cell re-sensitization is proven to be advantageous for boosting ROS-facilitated treatment of drug-resistant tumors, opening up new avenues for ROS therapy.