Fe- and Co-doped zinc oxide (ZnO) were successfully fabricated using laser-induced doping technology, with doping concentrations easily controllable by adjusting the feed ratio. This synthesis process required only ZnO and dopant sources as raw materials, without the need for additional chemical reagents. Both the Fe- and Co-doped ZnO powders showed enhanced degradation performance toward Acid Orange 7. This work introduces an effective general doping strategy for ZnO, thereby providing new insights into the preparation of single- or multi-metal doped oxides.

Thermodynamic immiscibility is a challenge for intermetallic alloying of sub-5 nm Ru-based alloys, which are excellent electrochemical catalysts for water splitting. In this study, nanosecond laser ultrafast confined alloying (LUCA) is proposed to break the immiscible-to-miscible transition limit in the synthesis of carbon nanotubes (CNTs) supported sub-5 nm bimetallic RuM (M = Cu, Rh, and Pd) alloy nanoparticles (NPs). The alloying of non-noble metal Cu with varying atomic ratios of RuCu alloys is appealing owing to the low price of Cu and cost-effective synthesis for large-scale practical applications. Benefiting from the synergistic alloying effect and resultant H/OH binding energy alteration, the Ru95Cu5/CNTs catalysts display excellent electrocatalytic alkaline hydrogen evolution reaction (HER) activity with an overpotential of 17 mV and Tafel slope of 28.4 mV dec-1 at 10 mA cm-2, and high robustness over long-term 5000 cyclic voltammetry cycles. The performance is much better than LUCA-synthesized CNTs-supported Ru86Rh14, Ru89Pd11, Ru, and Cu NPs catalysts, commercial benchmark 20% Pt/C, and other mainstream Ru-based catalysts including wet chemistry-synthesized RuRh particles (overpotential of 25 mV, Tafel slope of 47.5 mVdec-1) and RuCu/CNTs (overpotential of 39 mV) synthesized using the flash Joule heating method, indicating the great potential of LUCA for screening new classes of HER catalysts.

Iron-based oxides have been a focus point in the study of nanozymes since the discovery of the intrinsic enzymelike catalytic activity of Fe3O4. However, alpha-Fe2O3 has received limited attention due to its relatively low enzymelike catalytic efficiency, despite its considerable industrial potential and wide-ranging applications. In this work, we present the synthesis of metastable alpha-Fe2O3 nanodots (M-Fe2O3 NDs) using an innovative laser processing technique. The formation of the metastable structure is primarily attributed to laser-induced high temperature fragmentation and rapid quenching. M-Fe2O3 NDs exhibit remarkable peroxidase-like activity, attributed to their high specific surface area, the rapid regeneration of surface Fe2+ facilitated by the elevated Fe2+/Fe3+ ratio, and the strong affinity for H2O2 resulting from their weak-crystalline structure. The catalytic efficiency of M-Fe2O3 NDs was found to be 17,438 times higher than that of alpha-Fe2O3 nanoparticles before laser treatment and 87 times higher than that of Fe3O4 NDs of comparable size. Additionally, we have developed a highly sensitive glucose sensor by integrating M-Fe2O3 NDs with glucose oxidase. This development paves the way for the design of more efficient Fe-based oxidase nanozymes and the enhancement of glucose sensors.

PEGylation from Polyethylene glycol thiol (PEG-SH) can give gold nanoparticles (Au NPs) excellent chemical stability and biosafety, however, the stability of PEGylated AuNPs in applications at elevated temperature (50 degrees C similar to 100 degrees C) has been limited by the cleavage of Au-S bond to form disulfide bond (-S-S-). Such thermal disturbance can be effectively resisted by increasing the density of PEG-SH molecules on the surface of Au NPs to form dense brush conformation. However, because the binding sites on the surface of Au NPs are largely occupied by chemical agents during chemical synthesis, this conformation reported in most literatures has not reached the maximum loading capacity for Au NPs. How to improve the modification density and thermal disturbance resistance is still a key point. Here, we report that Au NPs with naked surface generated by laser treatment in liquids, which can successfully achieve a high grafting density up to 3.9 PEG/nm(2) for CH3O-PEG(5000)-SH. The dynamic evolution of PEG chains over time on Au NPs with varying grafting density was systematically investigated, along with their thermal stability and surface state changes at varied temperatures of 50, 75, and 100 degrees C. Under appropriate added amounts, PEG chains suffer from atom-binding on particle surface and rearrangement into a relatively uniform state within the first 6 h of coating. Whereas excessive addition leads to PEG chains entanglement, uneven initial coating distribution, and complex coating process. We demonstrated that, a grafting density of 2.8 PEG/nm(2) on Au NPs not only facilitates the rapid and uniform arrangement of PEG chains but also effectively withstands heating treatment up to 100 degrees C without irreversible shrinkage. Our efforts provide a significant foundation for advancing the development of PEG-SH-modified Au NPs for broader biomedical applications under elevated temperature.

Nanotwinned materials have attracted considerable attention in several fields owing to their numerous advantageous properties, such as excellent mechanical stability, high conductivity, and unique structural characteristics. However, twinning is highly unsuitable in face-centered cubic (fcc) metals with high stacking fault energy (SFE, such as Pt, Rh, Pd), because twinning nucleation in fcc crystalline materials is deemed to be accomplished through the formation of twinning partial dislocations on successive atomic planes. Here, we report a novel strategy for effectively introducing high-density twin boundaries and stacking faults into high SFE metal nanoparticles through laser fragmentation in liquids. The strategy is validated through detailed experimental characterization. The formation of the twin structure is mediated by rapid thermal quenching induced during laser fragmentation, which facilitates the preservation of transient atomic configurations. Molecular dynamics simulations indicate that the formation of twin boundaries is highly correlated with the cooling rate and particle size. Our work overcomes the limitation of twin-forming abilities of fcc metals with high SFE, providing not only a strategy for preparing multitwinned noble metal nanoparticles but also insights into laser-matter interactions.

Silver ions (Ag+) released from silver nanoparticles (Ag NPs) can help to improve the inhibition and killing ability of particles to bacteria. The leakage of Ag+ ions released from Ag NPs will lead to possible risks in cytotoxicity and environmental damage. It is still a challenge to balance particles' ions release and leakage to environment. Here, a nanocomposite of Ag NPs combined with reduced graphene oxide (rGO), labeled as rGO-Ag, was prepared by laser-induced photoreduction of Ag+ ions in solution. This composite exhibits not only a synergistic effect of Ag NPs and rGO in sterilization under normal circumstances, but also another synergistic effect from photothermal function under the 808 nm near-infrared (NIR) laser irradiation and the subsequent enhanced Ag+ ions release at high temperature. In experiments, rGO works as photothermal converter, which can directly cause the death of bacteria and force Ag+ ions to leave particle surface to assist in killing bacteria, and also as a catcher to intercepts the leakage of the released ions. After treating a 50 mg/L rGO-Ag solution with an NIR laser for 30 min, the concentration of released Ag+ ions increased, but these ions were subsequently adsorbed back onto the rGO. Compared with the no-light treatment group, the mortality rates of E. coli and S. aureus exposed to rGO-Ag under NIR irradiation increased by 39.06 % and 17.48 %, respectively. The clever combination between Ag NPs and rGO makes their composite exhibit a photo-enhanced synergistic sterilizing function, as well as a self-controlled ion release capability under NIR stimulation.

Interband and intraband electronic excitations in transition metals as nanocatalysts are crucial for the generation of hot carriers. Unlike the well-known Au, Ag and Cu nanoparticles (NPs), in which hot carriers are directly formed by absorption of visible light, Pt NPs still have limited hot carriers photogeneration ability. Nonetheless, Pt's unique d-band structure permits a high density of electronic states near Fermi energy. It should have exhibited photoenhanced catalysis. Here, guided by finite-different-time-domain (FDTD) calculations, we take advantage of Pt electronic structure by designing a sub-100 nm colloidosome (Cs) consisted of ultrasmall (≤ 5 nm) Pt NPs with broadband absorption from visible to near-infrared (NIR) band. The ultrasmall Pt NPs in the Cs efficiently generated hot electrons even under excitation with the low-energy electromagnetic radiation. The key for realization of Cs is the exploitation of laser-generated, grain boundaries (GBs) enriched Mn3O4 NPs as scaffolds for the efficient and homogeneous loading of ultrasmall Pt NPs. These Pt Cs show outstanding performances as catalase (CAT) and oxidase (OXD) mimics under NIR band irradiation, allowing their use for photocatalysis of oxidation reactions. Besides, the in vivo exploitation of Pt Cs for tumor photodynamic therapy allowed unprecedented efficacy and caused tumor growth suppression.

An oxygen-coordinated cobalt single-atom catalyst was successfully fabricated, exhibiting exceptional electrocatalytic activity toward urea and H 2 O 2 production. Subsequently, the value-added urea peroxide was efficiently synthesized.

In alkaline media, a crystalline platinum (Pt) electrocatalyst is essentially hindered by the sluggish water dissociation kinetics in the hydrogen evolution reaction (HER), which originates from the almost full filling of the d orbitals. Herein, carbon nanotube-supported few carbon-layer-encapsulated ternary PtNiRu (PtNiRu@C/CNT) nanoparticles (NPs) were designed via convenient laser irradiation in liquids (LILs). The PtNiRu@C/CNT catalysts showed an ultralow overpotential of 7 mV at 10 mA cm(-2) in alkaline media and more than 7 times higher mass activity of 1010 A g(-1) at an overpotential of 50 mV (45 mV @ 10 mA cm(-2) and a mass activity of 140 A/g for the Pt/C benchmark). In addition, the PtNiRu@C/CNT NPs still demonstrated good stability as well as decent activity after the durability test. Density function theory (DFT) calculations indicated that the introduction of oxophilic Ru accelerates the water dissociation, and the carbon layer confinement further facilitates the water dissociation as well as the subsequent *H adsorption, thus synergistically promoting the HER kinetics. As such, our work provides guidance and direction for the design of high-performance catalysts via a synergistic cascade strategy to enhance HER reaction kinetics.

Recently, sulfur quantum dots (SQDs) have gained great research interest because of their excellent optical properties and low toxicity, thus inspiring researchers to make efforts to explore a simpler and faster approach for the synthesis of SQDs. Herein, a facile and green bottom-up strategy is first proposed to prepare SQDs via 532 nm laser irradiation of a sulfate-containing solution without any extra additives. The reduction of sulfates to elemental sulfur under visible light is demonstrated for the first time. Furthermore, fluorescence characterization combined with density functional theory calculations revealed that the two-photon dissociation of sulfates plays a critical role in the formation of SQDs under laser irradiation. The nucleation mechanisms of self-assembling of sulfur element were revealed by molecular dynamics.

Diets consisting of selenium-deficient crops are associated with immune disorders and cardiomyopathy. Compared to the extensively used but highly toxic selenite (SeO32-), low-toxicity selenium nanoparticles (SeNPs) have emerged as a promising nanoplatform for Se biofortification in agriculture; however, the mechanisms underlying their transportation and biotransformation within crops remain elusive. In this study, SeNPs were successfully prepared using liquid-phase laser irradiation. We conducted a comparative study on the effects of foliar application of SeO32- and SeNPs on the growth of pak choi (Brassica chinensis L.), and investigated the absorption, translocation, and biotransformation mechanisms of Se in pak choi. The recommended dietary intake can be effectively achieved by applying SeNPs using leaf-spraying techniques. Our findings suggested that foliar application of SeNPs might be an efficient way to produce Se fortified crops, especially leafy vegetables, which are favorable for human health.

Herein, an electrocatalytic coupling system for selective ammonia and glycolic acid production over cathodic single-atom Co (Co & horbar;N & horbar;C) and anodic PdNi alloying nanoparticles on the carbonized cellulose (PdNi/CBC), respectively are reported. As a cathodic electrocatalyst for nitrate reduction reaction (NtrRR), the Co & horbar;N & horbar;C displays remarkably high activity, delivering an NH3 yield rate of 20.5 +/- 2.7 mg h-1 mgcat.-1 with a Faradaic efficiency (FE) of 95.5 +/- 2.8% at -0.5 V (vs RHE). In situ spectroscopy combined with theoretical calculations unveiled the NtrRR mechanism on Co & horbar;N4 site. As an anodic electrocatalyst for ethylene glycol oxidation reaction (EGOR), the PdNi/CBC shows a high FE of 96.6 +/- 1.7% for glycolic acid (GA) production at 1.6 V (vs RHE) and robust stability of 168 h. Remarkably, a proof of concept experiment of coupling electrocatalytic NtrRR with EGOR demonstrates that only an applied potential of -0.1 V (vs RHE) is required to reach a current density of 10 mA cm-2 for co-producing ammonia and glycolic acid. As a result, the coupled NtrRR-EGOR system can achieve an NH3 yield rate of 6.0 +/- 0.6 mg h-1 mgcat.-1 and a GA yield rate of 16.8 +/- 1.7 mg h-1 mgcat.-1 at -0.7 V (vs RHE).

Developing efficient electrocatalysts with high activity and stability for oxygen evolution reaction (OER) is of crucial importance. Herein, carbon shell encapsulated ultrafine FeNiOx NPs with an average size of 2.32 nm uniformly dispersing on CNT (denoted as FeNiOx@C-CNT) was synthesized via a simple laser irradiation tech-nique. The as-prepared FeNiOx@C-CNT composites present excellent electrocatalytic OER activity, mainly owing to the small size and high dispersion of FeNiOx NPs. Electrochemical measurement show that these com-posites possess a low overpotential of 267 mV at 10 mA cm-2 as well as a small tafel slope of 46.29 mV dec-1. Additionally, encapsulation in the carbon shell effectively preserve the FeNiOx NPs from degrading under the harsh external condition, showing almost unfading electrocatalytic activity after 20,000 potential cycles. Importantly, this strategy is universal and could be extended to synthesis other type of carbon shell encapsu-lated metal-based material (e.g. FeOx@C-CNT, CoOx@C-CNT, NiOx@C-CNT and MnOx@C-CNT), which might provide a new way to design high-efficiency electrocatalysts.

The present study was designed to investigate the role of miR-708-5p/p38 mitogen-activated protein kinase (MAPK) pathway during the mechanism of selenium nanoparticles (Nano-Se) against nickel (Ni)-induced testosterone synthesis disorder in rat Leydig cells. We conducted all procedures based on in vitro culture of rat primary Leydig cells. After treating Leydig cells with Nano-Se and NiSO4 alone or in combination for 24 h, we determined the cell viability, reactive oxygen species (ROS) levels, testosterone production, and the protein expression of key enzymes involved in testosterone biosynthesis: steroidogenic acute regulatory (StAR) and cytochrome P450 cholesterol side chain cleavage enzyme (CYP11A1). The results indicated that Nano-Se antagonized cytotoxicity and eliminated ROS generation induced by NiSO4 , suppressed p38 MAPK protein phosphorylation and reduced miR-708-5p expression. Importantly, we found that Nano-Se upregulated the expression of testosterone synthase and increased testosterone production in Leydig cells. Furthermore, we investigated the effects of p38 MAPK and miR-708-5p using their specific inhibitor during Nano-Se against Ni-induced testosterone synthesis disorder. The results showed that Ni-inhibited testosterone secretion was alleviated by Nano-Se co-treatment with p38 MAPK specific inhibitor SB203580 and miR-708-5p inhibitor, respectively. In conclusion, these findings suggested Nano-Se could inhibit miR-708-5p/p38 MAPK pathway, and up-regulate the key enzymes protein expression for testosterone synthesis, thereby antagonizing Ni-induced disorder of testosterone synthesis in Leydig cells.

Designing effective catalysts with high performance for electrocatalytic hydrogen production remains a formidable challenge. Small-size bimetallic alloy nanoparticles (NPs) with the advantages of a large ex-posure of effective active sites and optimal geometric/electronic effects are of great interest in the field of electrocatalysis, yet a suitable strategy for synthesizing such unique structures is still highly expected. In this effort, we report a unique approach to synthesizing ultra-small bimetallic PtM (M=Ni, Co) alloy NPs (similar to 1.7 nm) on carbon supports by laser irradiation in liquids. The method is based on the effective absorption of pulse laser energy by carbon supports to generate instant high temperature, which allows the reduction of metallic ions precursors by ethanol molecules and ensures the subsequent formation of alloy NPs. The fast -cooling dynamic process stops the further growth of small-sized alloy NPs. Such bimetallic PtNi alloy NPs displayed much improved catalytic performance in the HER process. The overpotential is only 19 mV and 42 mV (10 mA cm-2) in acidic and alkaline conditions, which is much lower than that of commercial 20 % Pt/ C (36 mV, 53 mV) catalyst. Density function theory calculation shows that Ni doping facilitates the hydrogen adsorption/desorption process of nearby surface Pt atoms.(c) 2022 Elsevier B.V. All rights reserved.

Nanozymes with oxidase (OXD) mimic activity have shown great prospects for biomarker sensing, but their lower activity compared to natural enzymes has limited their further application. The catalytic activity of OXD mimics can be remarkably improved by material morphology design and defect engineering. In this work, we developed MnOx nanobelts (NBs) using a laser irradiation in liquid (LIL) technique. Among the MnOx NB structure, the ultrathin layered structure was conducive to exposing the catalytic active sites of the MnOx NBs, and the negative charge layer of the birnessite-type MnOx NBs helped to improve the affinity for positive sub-strate 3,3',5,5'-tetramethylbenzidine (TMB). Importantly, laser-irradiation-generated oxygen vacancies signifi-cantly reduced the adsorption energy of the MnOx NBs for oxygen. As expected, the excellent substrate affinity (Km = 0.0087 mM) and high catalytic rate (Vmax = 6.04 x 10-7 M/s) of the MnOx NBs as OXD mimics were verified. Meanwhile, based on the inhibition of glutathione (GSH) on the OXD mimics, we established a fast and highly sensitive method for GSH determination. These new findings may provide a new strategy for synthesizing highly active nanozymes for biomarker applications.

Abstract Noble metal nanoparticles (NPs) are photo-responsive substrates that generate hot electrons under light excitation, and these hot electrons enhance the catalytic capability of the NPs, which is useful in many applications. For ultrasmall (≤ 5 nm) Pt NPs with excellently catalytic performance, it is challenging to utilize near-infrared (NIR) light-excited hot electrons to enhance the nanozyme activities of Pt NPs for tumor catalytic therapy because ultrasmall Pt NPs have no obvious absorption from the visible light band to the NIR band. Herein, we report on constructing Pt colloidosomes (Cs) with ultrasmall Pt NPs to elevate NIR light absorption to excite multitudes of hot electrons. The successful photon-to-electron conversion is based on the high density of electron states (d-band) at the Fermi energy in the Pt system, which leads to a high probability of generating NIR photon-excited hot electrons. NIR light absorption of Pt Cs is optimized by introducing grain boundaries (GBs) defects in Mn3O4 precursors by laser irradiation in liquids. Moreover, NIR photon-excited hot electrons largely promote the self-cascade catalytic production of reactive oxygen species (ROS) for enhanced tumor therapy. This study first validates the generation of hot electrons in the Pt nanostructure under NIR light irradiation by assembling ultrasmall Pt NPs, and then demonstrates the Pt Cs to be highly promising as efficient photo-responsive nanozymes with integrated photoactivity and chemical activity.

The effects of silver nanoparticles (Ag NPs) on the soil environment have attracted considerable research attention. Previous studies mainly focused on agent‐coated Ag NPs, which inevitably introduce additional disturbance of chemical agents to the intrinsic property of Ag NPs. We investigated the environmental effects induced by pure surfactant‐free Ag NPs (SF‐Ag NPs), including soil enzyme activities (urease, sucrase, phosphatase, and β‐glucosidase), bacterial community structure, and functional profile, over different exposure periods in the present study. The results indicated that these enzymes, especially urease and phosphatases, exhibit different responses to SF‐Ag NPs and are more susceptible to SF‐Ag NPs than other enzymes. Surfactant‐free Ag NPs can also induce a decrease in bacterial diversity and a change of bacterial community structure. The abundance of SF‐Ag NPs in Proteobacteria increased, but decreased in Acidobacteria after 14 days of exposure. Moreover, the abundance of genus Cupriavidus was significantly higher than those of the respective controls. By contrast, SF‐Ag NP exposure for 30 days could attenuate these negative effects. The phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) prediction revealed that SF‐Ag NPs exert a negligible effect on bacterial function, thereby suggesting that functional redundancy is conduced to bacterial community tolerance to SF‐Ag NPs. These findings will help us further understand the environmental toxicity of Ag NPs. Environ Toxicol Chem 2023;42:1685–1695. © 2023 SETAC

PdCu/CBC exhibited a remarkable R urea of 763.8 ± 42.8 μg h −1 mg cat. −1 at −0.50 V ( vs. RHE) and an exceptional FE of 69.1 ± 3.8% at −0.40 V ( vs. RHE). Taking advantage of operando spectroscopy characterization, the C–N coupling mechanism was verified.