In situ monitoring of the plasmon catalytic reaction of p-nitroaniline at a gas-liquid-solid three phase interface.

Localized surface plasmon resonance (LSPR) is caused by the irradiation of light on a metal surface. Here we present a surface plasmon catalytic reaction at the gas-liquid-solid three phase interface. Electrochemical deposition was used to prepare Ag nanostructure/Cu mesh surface-enhanced Raman scattering (SERS) substrates. Surface wettability was adjusted by changing the processing time of the surfactant. Then a three-phase interface platform was constructed with good SERS performance and active surface plasmon catalytic capacity by droplet detection. At the gas-liquid-solid three phase interface, different oxygen supplies for the catalytic reaction were offered on surfaces with different wettability values. Thus, in this study, surface plasmon catalytic reaction of p-nitroaniline (PNA) was successfully in situ monitored and the reaction mechanism was explored. Otherwise, density functional theory (DFT) was used to calculate the Raman spectra and energy levels of the reactants and reaction products. Moreover, this work provides a new platform for monitoring the surface plasmon reaction at the gas-liquid-solid three-phase interface and contributes to the development of the study in the surface plasmon catalytic reaction field.

Exploring the surface plasmon catalytic reactions mechanism by three-phase interface modification combining with in-situ EC-SERS methods.

Local surface plasmon resonance (LSPR) is a novel catalytic technique that has emerged in recent years, especially in the catalysis of aromatic amine compounds. However, the response process and mechanism are still unclear in current study. In the current field of study, the response process and mechanism are still unclear. In this work, the gas-liquid-solid three-phase interface (GLSTI) was innovatively utilized in this study to validate the reaction mechanism by surface-enhanced Raman spectroscopy. P-Aminothiophenol (PATP) and P-Phenylenediamine (PDA) underwent a surface plasmon-catalyzed reaction by using a silver nano-dendrites substrate with strong SERS activity. The GLSTI significantly facilitates the occurrence of surface plasmon catalytic reactions, which can supply enough oxygen by providing three-phase points. In situ SERS and EC-SERS technologies were combined in this study for the explorations. Therefore, this work is dedicated to deepening the exploration and expanding into new directions in plasmon-induced catalytic reactions.

A novel SERS sensor array based on AuNRs and AuNSs inverse-etching for the discrimination of five antioxidants.

Antioxidants play an important role in life health and food safety. Herein, an inverse-etching platform based on gold nanorods (AuNRs) and gold nanostars (AuNSs) for high-throughput discrimination of antioxidants was constructed. Under the action of hydrogen peroxide (H2O2) and horseradish peroxidase (HRP), 3,3',5,5'-tetramethylbenzidine (TMB) would be oxidized to TMB+ or TMB2+. HRP reacts with H2O2 to release oxygen free radicals, which then react with TMB. Au nanomaterials can react with TMB2+, at the same time, Au was oxidized into Au (I), leading to the etching of the shape. Antioxidants, with good reduction ability, would prevent the further oxidation of TMB+ to TMB2+. So the presence of antioxidants will prevent further oxidation while avoiding the etching of Au in the catalytic oxidation process, thereby achieved inverse etching. Distinctive surface enhanced Raman scattering (SERS) fingerprint of five antioxidants were obtained based on the differential ability to scavenge free radicals. Five antioxidants, including ascorbic acid (AA), melatonin (Mel), glutathione (GSH), tea polyphenols (TPP), and uric acid (UA) were successfully distinguished by using linear discriminant analysis (LDA), heat map analysis and hierarchical cluster analysis (HCA). The study exhibits an effective inverse-etching based SERS sensor array for the response of antioxidants, which has great reference value in the field of human disease and food detection.

Symmetry-Breaking p-Block Antimony Single Atoms Trigger N-Bridged Titanium Sites for Electrocatalytic Nitrogen Reduction with High Efficiency.

The electrochemical nitrogen reduction reaction (eNRR) under mild conditions emerges as a promising approach to produce ammonia (NH3) compared to the typical Haber-Bosch process. Herein, we design an asymmetrically coordinated p-block antimony single-atom catalyst immobilized on nitrogen-doped Ti3C2Tx (Sb SA/N-Ti3C2Tx) for eNRR, which exhibits ultrahigh NH3 yield (108.3 µg h-1 mgcat-1) and excellent Faradaic efficiency (41.2%) at -0.3 V vs RHE. Complementary in situ spectroscopies with theoretical calculations reveal that the nitrogen-bridged two titanium atoms triggered by an adjacent asymmetrical Sb-N1C2 moiety act as the active sites for facilitating the protonation of the rate-determining step from *N2 to *N2H and the kinetic conversion of key intermediates during eNRR. Moreover, the introduction of Sb-N1C2 promotes the formation of oxygen vacancies to expose more titanium sites. This work presents a strategy for single-atom-decorated ultrathin two-dimensional materials with the aim of simultaneously enhancing NH3 yield and Faradaic efficiency for electrocatalytic nitrogen reduction.

Surface enhanced Raman scattering of adsorbates on Au-CsPbIBr2 perovskite-based nanocomposites: charge-transfer and electromagnetic enhancement.

In this study, perovskite-based nanocomposites as surface enhanced Raman scattering substrates were designed by physically sputtering Au nanoparticles onto fabricated all-inorganic CsPbIBr2 perovskite films, which provide much stronger SERS signals as compared to normal Au or perovskite substrates. Their synergism enhancement mechanisms and influence factors, including hybrid layer sequence, fabrication parameters and excitation source, are discussed. In addition, the prepared composite substrate exhibits excellent uniformity, reproducibility and time stability. This study promotes an easily prepared perovskite-based substrate for SERS-related applications and develops further understanding of molecule-semiconductor-noble metal nanostructure interfacial interactions.

A three-dimensional "turn-on" sensor array for simultaneous discrimination of multiple heavy metal ions based on bovine serum albumin hybridized fluorescent gold nanoclusters.

Traditional single sensor is designed based on the "lock-and-key" mode, which only relies on the most dominant interactions between the sensing element and the target. Although it exhibits high selectivity, there are challenges in detecting multiple analytes at the same time. Here, a sensor array with three sensing elements is developed to detect multiple heavy metal ions simultaneously and quickly. In our experiment, bovine serum albumin-encapsulated gold nanoclusters (BSA-AuNCs) were used as fluorescence probes and three different dopamine (DA) concentrations as nonspecific receptors. As we know, self-polymerized polydopamine (PDA) can quench part of the fluorescence of BSA-AuNCs. Upon the addition of the heavy metal ions, the diverse non-specific interactions between DA and heavy metal ions result in the difference in the number of the remaining PDA. Therefore it would lead to different degrees of fluorescence recovery behavior. This unique "turn-on" fluorescence response mode can be analyzed by linear discriminant analysis (LDA) and hierarchical cluster analysis (HCA). Two-dimensional, three-dimensional and even four-dimensional mixed ions detection and quantitative detection have also been achieved. Moreover, by using this fluorescence array mode, heavy metal ions in tap water or blood samples can be detected.