Biosensors featuring single molecule detection present huge opportunities as well as challenges in food safety inspection, disease diagnosis, and environmental monitoring. Single‐molecule detection is largely lacking of high enough activity, precision molecule selectivity, and understanding in the exact operating mechanism. Single‐atom catalysts (SACs), especially those metals‐nitrogen‐carbon that mimic the natural metalloenzyme structure, and with well‐defined metal atom bond configurations, high level of molecular selectivity, and easy fabrication, endow single molecule detections with practical‐use feasibilities. The recent advances in single‐atom catalysts also present new pathways in the key mechanism understandings. In this short review, we will first visit the brief history and advantages of SACs that have been explored only recently for molecule‐scale biosensors, where they are analogous and also differentiated from those nanozymes and natural metalloenzymes. Their applications in electrochemical, photochemical, and photoelectrochemical sensors are then discussed comprehensively by focusing on the different molecule‐scale sensing modes in achieving local coordination‐modulated signal amplifications. Finally, we identify new opportunities and challenges faced by these SACs‐based single molecule detections in the further development of biosensors. image

The slow diffusion dynamics hinder aqueous MnO₂/Zn batteries’ further development. Here, a Ni/Fe bimetallic co-doped MnO₂ (NFMO) cathode material was studied by density functional theory (DFT) calculation and experimental characterization techniques, such as cyclic voltammetry (CV), galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectra (EIS). The results indicated that the energy band structure and electronic state of MnO₂ were effectively optimized due to the simultaneous incorporation of strongly electronegative Ni and Fe ions. Consequently, the NFMO cathode material exhibited a faster charge transfer and ion diffusion dynamics than MnO₂ (MO), thus, the assembled NFMO/Zn batteries delivered excellent rate performance (181 mA h g⁻¹ at 3 A g⁻¹). The bimetallic ions co-doping strategy provides new directions for the development of oxide cathode materials towards high-performance aqueous zinc-ion batteries.

As a well-known greenhouse gas, carbon dioxide (CO₂) has attracted increasing levels of attention in areas of energy, environment, climate, etc. Notably, CO₂ is an abundant, nonflammable, and renewable C1 feedstock in view of chemistry. Therefore, the transformation of CO₂ into organic compounds is an extremely attractive research topic in modern green and sustainable chemistry. Among the numerous CO₂ utilization methods, carboxylative cycloaddition of CO₂ into propargylic alcohols is an ideal route due to the corresponding products, α-alkylidene cyclic carbonates, which are a series of highly functionalized compounds that supply numerous potential methods for the construction of various synthetically and biologically valuable agents. This cyclization reaction has been intensively studied and systematically summarized, in the past years. Therefore, attention has been gradually transferred to produce more derivative compounds. Herein, the tandem reactions of this cyclization with hydration, amination, alcoholysis, and isomerization to synthesize α-hydroxyl ketones, oxazolidinones, carbamates, unsymmetrical carbonates, tetronic acids, ethylene carbonates, etc. were systematically reviewed.