Sub-nanometer-precision of noble metal catalysts with atomic contact to support simultaneously played a pivotal role in determining their catalytic activities. However, achieving predictable construction of noble metal cocatalysts at sub-nanometer scales remained a significant challenge. Herein, we demonstrated an in situ lattice atom abstraction strategy for sub-nanometer-precision construction of size-controlled Ag cocatalysts. Host lattice Ag⁺ was abstracted by tri-n-octylphosphine (TOP) due to its strong complexing ability towards Ag⁺, and was in situ reduced into metal Ag cocatalysts on the surface of AgInS₂ nanorods (AIS NRs), which was accelerated by the synergistic effect of TOP and oleylamine (OAm). This in situ lattice atom abstraction strategy avoided the undesired cation exchange reaction and simplified complex reaction processes, facilitating Ag cocatalysts with controlled sizes ranging from 0.60 to 6.76 nm with an unprecedented sub-nanometer precision. This set of Ag cocatalysts with sub-nanometer precision provided an ideal platform for systematically investigating cocatalyst size effects. Nano-sized Ag cocatalysts possessed superior separation and transfer ability over cluster-sized Ag cocatalysts, leading to the enhancement of photocurrent density 2.78 times higher than cluster-sized Ag cocatalysts. While cluster-sized Ag cocatalysts possessed higher surface catalytic activity, contributing to the improvement of Faradaic efficiency up to 97.5% from 74.4%.

Quantum dots (QDs) are positioned to revolutionize point-of-care testing (POCT), with their exceptional brightness, photostability, and multiplexing capabilities being leveraged to enable real-time, in-situ detection with practical utility. In this review, recent advances in QD-based sensing are systematically summarized, with emphasis placed on how precise control over synthesis and surface functionalization across key material families (e.g., chalcogenide QDs) has facilitated the development of a versatile analytical toolkit. Diverse transduction mechanisms, including fluorescence, colorimetric, electrochemiluminescence, photoelectrochemical, and chemiresistive sensing, are explored, and their deployment across biomedical diagnostics, environmental surveillance, and food safety is highlighted. Moving beyond a mere summary of progress, this review focuses on addressing the critical challenges that currently hinder the practical translation of QD-based sensing technologies. Key issues include the biotoxicity of heavy-metal-containing QDs, their limitation in complex sample matrices, performance gaps in emerging “green” QDs, and hurdles in device integration and data analysis. A coordinated strategy is therefore proposed, centered on greenification, intellectualization, and integration. It is envisioned that through advances in biocompatible materials, integration with portable platforms such as microfluidics and smartphones, and the incorporation of machine learning for intelligent signal processing, QDs will be propelled from laboratory tools into foundational, democratized technologies for next-generation POCT. The strategic framework presented here provides a clear roadmap to guide future research and translation efforts in QD-POCT.

Quantum dots (QDs) have been widely applied in bioimaging and oncological therapeutics owing to their unique photophysical and photochemical properties. However, conventional QDs typically require excitation from an external light source, which restricts their utility to in vivo imaging and treatment of deep-seated tissues and metastatic tumours. Conversely, radionuclides can achieve deep tissue imaging and treatment without external light source, yet they often lack multifunctional applications. Radioactive quantum dots (RQDs) emerge as an integrative solution that overcomes the limitations of both constituent materials. By harnessing the decay energy of radionuclides for self-excitation, RQDs overcome the penetration barrier of conventional QDs. Simultaneously, they incorporate the rich photophysics of QDs to achieve high-resolution multimodal imaging and combination therapy, thereby circumventing the lack of multifunctionality in radionuclides. This review mainly summarises the properties of RQDs, their synthesis strategies and their applications in bioimaging and cancer therapeutics. Finally, we discuss the future potential of RQDs in the integration of tumour diagnosis and treatment, aiming to provide guidance for researchers in medicine and engineering.

Spermine assumes a pivotal role in assessing food safety due to its potential to induce a spectrum of diseases upon excessive consumption. However, contemporary spermine detection methodologies, exemplified by high-performance liquid chromatography (HPLC), demand costly instrumentation and the expertise of skilled technicians. To address this challenge, the study introduces a portable fluorescence sensing platform. Ratiometric fluorescent probes were realized through the utilization of CdS quantum dots deeply doped with Ag⁺ (CdS:Ag QDs) and nitrogen-doped carbon quantum dots (N-CQDs). Hydrogen bonds formed between CdS:Ag QDs and spermine result in the formation of the assembly and the decreasing of the fluorescence intensity. In an effort to broaden the applicative scope and streamline deployment processes, fluorescent sensing hydrogels were meticulously engineered, capitalizing on the swelling properties inherent in polyvinyl alcohol (PVA) hydrogels. The systematic delineation of the correlation between 1 − R/B and spermine concentration facilitates the quantitative determination of spermine concentration. The incorporation of this composite construct serves to alleviate environmental influences on the probes, thereby augmenting their precision. The portable fluorescent sensing platform proves pivotal in expeditiously measuring spermine concentration within the fluorescent sensing hydrogel, enabling a quantitative assessment of pork freshness. The utilization of this platform for food freshness evaluation imparts the benefits of convenience, cost-effectiveness, and intuitive operation.

Single atom (SA) catalysts have achieved great success on highly selective heterogeneous catalysis due to their abundant and homogeneous active sites. The electronic structures of these active sites, restrained by their localized coordination environments, significantly determine their catalytic performances, which are difficult to manipulate. Here, we investigated the effect of localized surface plasmon resonance (LSPR) on engineering the electronic structures of single atomic sites. Typically, core–shell structures consisted of Au core and transition metal SAs loaded N-doped carbon (CN) shell were constructed, namely Au@M-SA/CN (M = Ni, Fe, and Co). It was demonstrated that plasmon-induced hot electrons originated from Au were directionally injected to the M-SAs under visible light irradiation, which significantly changed their electronic structures and meanwhile facilitated improved overall charge separation efficiency. The as-prepared Au@Ni-SA/CN exhibited highly efficient and selective photocatalytic CO₂ reduction to CO performance, which is 20.8, 17.5, and 6.9 times those of Au nanoparticles, Au@CN, and Ni-SA/CN, respectively. Complementary spectroscopy analysis and theoretical calculations confirmed that the plasmon enhanced Ni-SA/CN sites featured increased charge density for efficient intermediate activation, contributing to the superb photocatalytic performance. The work provides a new insight on plasmon and atomic site engineering for efficient and selective catalysis.

Carbon-based single-atom catalysts (SACs) have been widely studied in the field of biomedicine due to their excellent catalytic performance. However, carbon-based SACs usually aggregate during pyrolysis, which leads to the reduction of catalytic activity. Here, we describe a method to improve the monodispersion of SACs using silicon dioxide as a protective layer. The decoration of silicon dioxide serves as a buffer layer for individual nanoparticles, which is not destroyed during the pyrolysis process, ensuring the single-particle dispersion of the nanoparticles after etching. This approach increased the hydroxyl groups on the surface of Fe-SAC (Fe-SAC-SE) and improved its water solubility, resulting in a four times enhancement of the peroxidase (POD)-like activity of Fe-SAC-SE (58.4 U/mg) than that of non-protected SACs (13.9 U/mg). The SiO₂-protection approach could also improve the catalytic activities of SACs with other metals such as Mn, Co, Ni, and Cu, indicating its generality for SACs preparation. Taking advantage of the high POD-like activity, photothermal properties, and large specific surface area of Fe-SAC-SE, we constructed a synergistic therapeutic system (Fe-SAC-SE@DOX@PEG) for combining the photothermal therapy, catalytic therapy, and chemotherapy. It was verified that the photothermal properties of Fe-SAC-SE@DOX@PEG could effectively improve its POD-like activity, exhibiting excellent tumor-killing performance at the cellular level. This work may provide a general approach to improve the performances of SACs for disease therapy and diagnosis.

Active site exposure and intrinsic catalytic performance are considered important aspects of oxygen evolution reaction catalyst design. In this work, the coordination capacity of tributylphosphine is utilized to construct cationic vacancy defects on NiFe-LDH nanosheets. As-prepared defective NiFe-LDH nanosheets show not only the optimization of the exposure ability of the active site but also the intrinsic catalytic capacity is improved by construction of cationic vacancy defect to tune local electronic structure. The x-ray photoelectron spectroscopy results revealed that after reconstruction of the prepared d-NiFe-LDH, high-valence Ni and Fe can stably appear on the surface of the material. The presence of high-valence Ni and Fe is considered to be the main reason to improve the intrinsic catalytic capacity of catalysts. Finally, d-NiFe-LDH nanosheets show excellent catalytic performance (η₁₀ = 243 mV) and remarkable long-term stability.

The semiconductor-based photoanodes have shown great potential on photoelectrochemical (PEC) hydrogen generation. Compared to the pristine semiconductor, photoanodes fabricated with doped semiconductors exhibit modulated bandgap structure and enhanced charge separation efficiency, demonstrating improved optoelectronic properties. In this work, we develop a colloidal cation exchange (CE) strategy on versatile synthesis of heterovalent doped chalcogenide semiconductor thin films with high surface roughness. Using Ag-doped CdSe (CdSe:Ag) thin films as an example, the organized centimeter-scale CdSe:Ag films with nanometer-scale thickness (thickness around 80 nm, length × width around 1.5 cm × 1.2 cm) exhibit enhanced optical absorbance ability and charge carrier density by tuning the energy levels of conduction and valence bands as well as improved electrical conductivity by Ag dopants compared to the pristine CdSe film obtained by the vapor-phase vacuum deposition strategy. In the meantime, the surface roughness of the as-prepared semiconductor thin films is also increased with abundantly exposed active sites to facilitate accessibility to water for hydrogen generation and suppress photogenerated carrier recombination. The CdSe:Ag film photoanodes exhibit superb PEC hydrogen generation performance with a photocurrent density of 0.56 mA/cm² at 1.23 V versus reversible hydrogen electrode, which is nearly 3 times higher than the pristine CdSe film. This work provides a new strategy on colloidal synthesis of photoelectrodes with modulated heterovalent doping and surface roughness for PEC applications.

Oxidative stress and inflammation are central pathophysiological processes in a traumatic spinal cord injury (SCI). Antioxidant therapies that reduce the reactive oxygen and nitrogen species (RONS) overgeneration and inflammation are proved promising for improving the outcomes. However, efficient and long-lasting antioxidant therapy to eliminate multiple RONS with effective neuroprotection remains challenging. Here, a single-atom cobalt nanozyme (Co-SAzyme) with a hollow structure was reported to reduce the RONS and inflammation in the secondary injury of SCI. Among SAzymes featuring different single metal-N sites (e.g., Mn, Fe, Co, Ni, and Cu), this Co-SAzyme showed a versatile property to eliminate hydrogen peroxide (H₂O₂), superoxide anion (O₂^•−), hydroxyl radical (·OH), nitric oxide (·NO), and peroxynitrite (ONOO⁻) that overexpressed in the early stage of SCI. The porous hollow structure also allowed the encapsulation and sustained release of minocycline for neuroprotection in synergy. In vitro results showed that the Co-SAzyme reduced the apoptosis and pro-inflammatory cytokine levels of microglial cells under oxidative stress. In addition, the Co-SAzyme combined with minocycline achieved remarkable improved functional recovery and neural repairs in the SCI-rat model.

Electronic doped quantum dots (Ed-QDs), by heterovalent cations doping, have held promise for future device concepts in optoelectronic and spin-based technologies due to their broadband Stokes-shifted luminescence, enhanced electrical transport and tailored magnetic behavior. Considering their scale-up requirement and the low yielding of several current colloidal synthesis methods, a stable and efficient bulk synthesis strategy must be developed. Microreactors have long been recognized as an effective platform for producing nanomaterials and fabricating large-scale structures. Here, we chose microreactor platform for continuous synthesis of Ed-QDs in the air at low temperatures. By original reverse cation exchange reaction mechanism together with varying the kinetic conditions of microreactor platform, such as liquid flow rate, the Ag doped CdS (CdS:Ag) Ed-QDs with higher yield have been synthesized successfully due to the continuous synthesis advantages with a high degree of size selectivity. Enabled by microreactor engineering simulation, this research not only provides a new synthetic method towards scale-up production but also enables to improve chemical mass production of similar functional QDs for optical devices, bio-imaging and innovative information processing applications.