Incorporation Of Noble Metals Research Articles

Platinum nanoparticles decorated TiO2 nanotubes for VOCs and bacteria removal in simulated real condition: Effect of the deposition method on the photocatalytic degradation process efficiency

The incorporation of noble metals onto TiO2 nanostructure is considered as a promoting method to enhance the photocatalytic degradation of pollutant in air treatment process. In this study, highly organized TiO2 nanotubes (NTs) were grown by the anodization method of Titanium substrates. The TiO2-NTs were successfully decorated by platinum (Pt) nanoparticles (NPs) using two different deposition methods: (1) electrodeposition and (2) photodeposition.We explore the impact of different deposition methods on the morphology of Pt nanoparticles (NPs) dispersed onto TiO2 nanotubes and the optical characteristics of Pt-TiO2 nanocomposites, investigating their efficacy in photocatalytic degradation We investigate the effect of varying the deposition method on the morphology of Pt-NPs dispersed onto TiO2 nanotubes and the optical properties of the Pt-TiO2 nanocomposites and their efficient photocatalytic activity degradation against Volatile Organic Compounds (VOCs) and bacteria. Scanning and Transmission Electron Microscopy (SEM and TEM) reveal a nanotubular TiO2 anatase structure adorned with Pt NPs, with the quantity and size of NPs contingent upon the deposition technique employed. The photoluminescence (PL) spectra demonstrate that the Pt/TiO2 heterojunction facilitates the separation of photogenerated charges, thereby diminishing carrier recombination rates. To point out the effect of Pt NPS, both pure TiO2 and Pt/TiO2 heterojunction were tested in the photodegradation of Ethyl Acetate (EA). The Pt/TiO2 heterojunction exhibits superior photocatalytic performance compared to TiO2 in EA degradation, regardless of the Pt deposition method employed. Optimal results are achieved with 120 s of Pt electrodeposition and 3 h of Pt photodeposition under visible irradiation, yielding kinetic constants of approximately 0.245 and 0.195 mg.m−3.s−1, respectively, underscoring the pivotal role of the platinum deposition method in pollutant photodegradation. Respectively simultaneous removal of EA and bacteria (Escherichia coli) was tested using Pt and non-Pt decorated TiO2 NTs. We attributed a total degradation of the bacteria after 180 min using the two efficient photocatalysts Electro 120 s and Photo 3 h compared to 60 % of degradation using pure TiO2 nanotubes.

Advancing Adsorption and Separation with Modified SBA-15: A Comprehensive Review and Future Perspectives.

Mesoporous silica SBA-15 has emerged as a promising adsorbent and separation material due to its unique structural and physicochemical properties. To further enhance its performance, various surface modification strategies, including metal oxide and noble metal incorporation for improved catalytic activity and stability, organic functionalization with amino and thiol groups for enhanced adsorption capacity and selectivity, and inorganic-organic composite modification for synergistic effects, have been extensively explored. This review provides a comprehensive overview of the recent advances in the surface modification of SBA-15 for adsorption and separation applications. The synthesis methods, structural properties, and advantages of SBA-15 are discussed, followed by a detailed analysis of the different modification strategies and their structure-performance relationships. The adsorption and separation performance of functionalized SBA-15 materials in the removal of organic pollutants, heavy metal ions, gases, and biomolecules, as well as in chromatographic and solid-liquid separation, is critically evaluated. Despite the significant progress, challenges and opportunities for future research are identified, including the development of low-cost and sustainable synthesis routes, rational design of SBA-15-based materials with tailored properties, and integration into practical applications. This review aims to guide future research efforts in developing advanced SBA-15-based materials for sustainable environmental and industrial applications, with an emphasis on green and scalable modification strategies.

Enhanced Femtosecond Nonlinear Optical Susceptibility and Terahertz Conductivity in MoSe2‐Noble Metal Nanocomposites

AbstractCreating heterojunctions or composites by incorporating noble metals offers a remarkable means to modulate the electronic charge transfer and the nonlinear optical (NLO) properties in 2D transition metal dichalcogenides (TMDCs). The response of such 2D‐TMDC‐noble metal composites to femtosecond (fs) infrared (IR) and terahertz (THz) radiation, however, remains vastly unexplored. While the linear optical characteristics of a prototypical 2D‐TMDC, namely, MoSe2 nanosheets incorporated with noble metal (such as Au, Pt, and Ag) nanoparticles in the UV–Vis and the THz spectral range, the NLO characteristics are measured using a 70‐fs pulse at 800 nm excitation is investigated. The results demonstrate a clear reduction of band gap with the incorporation of noble metals in MoSe2, indicating an effective charge transfer mechanism at play. Notably, the MoSe2‐noble metal nanocomposites depicted a significant enhancement in the THz conductivities. In addition, a dramatic 4‐fold enhancement in the third‐order nonlinear coefficient and ≈2‐fold enhancement in the third‐order NLO susceptibility is achieved in MoSe2‐Ag nanocomposite. These results univocally suggest that the noble metal‐based composites with suitable charge transfer channels promote enhanced carrier mobilities and tunable electron transfer dynamics, making these hybrid materials promising candidates for optoelectronic applications both at IR and THz frequencies.

Enhanced photocatalytic hydrogen generation using UiO-66(Zr) MOF with tailored modifications: A review

The utilization of UiO-66 MOF-based photocatalytic materials has achieved significant attention for their potential in hydrogen generation, owing to their remarkable stability and porous crystalline structure. Recent studies have disclosed enhanced light absorption capabilities in UiO-66 through both pre and post-synthetic modifications. These modifications also play a significant role in mitigating the recombination of photogenerated charge carriers by facilitating electron transfer in hybrid or derived materials. Designing of MOF-based modified improved photocatalyst includes, integration with other low band gap semiconductors, incorporation of noble metals as co-catalysts, surface engineering, inclusion of defects or introduction of heteroatom in the framework. MOF-COF hybridization, dye sensitization etc., further reinforced photocatalytic hydrogen yield. The above-mentioned comprehensive investigations have researched into aspects such as morphology, hydrogen generation efficiency, and the underlying mechanisms. It reveals that the creation of heterojunctions at interface channelizes the separation and smooth flow of electrons resulting in suppression of recombination reaction and favorable photocatalytic properties. The synergy between the components often results in enhanced performance. The present article provides a comprehensive review of modified UiO-66 MOF-based materials investigated for photocatalytic hydrogen generation.

Simultaneous Electrochemical Detection of Dopamine and Uric Acid via Au@Cu-Metal Organic Framework.

The incorporation of noble metals with metal-organic frameworks (MOFs) are conducive to the simultaneous electrochemical detection of analytes owing to multiple accessible reaction sites. Herein, Au@Cu-metal organic framework (Au@Cu-MOF) is successfully synthesized and modified as a screen-printed carbon electrode (SPCE), which serves as an excellent electrocatalyst for the oxidation of dopamine (DA) and uric acid (UA). The sensor shows a linear range from 10 μM to 1000 μM, with sensitivity and detection limit of 0.231 μA μM-1 cm-2 and 3.40 μM for DA, and 0.275 μA μM-1 cm-2 and 10.36 μM for UA. Au@Cu-MOF could realize the individual and simultaneous electrochemical sensing of DA and UA, with distinguishable oxidation peak potentials. Moreover, it exhibits reproducibility, repeatability, and stability. Ultimately, the sensor provides an avenue for an ultrasensitive label-free electrochemical detection of DA and UA.

Critical assessment of a TiO2-Ag-ZnO nanocomposite photocatalyst on improved photocatalytic activity under mixed UV-visible light

In recent years, semiconductor photocatalysts such as zinc oxide (ZnO) and titanium dioxide (TiO2) have been studied to utilize solar light for energy production and environmental remediation. However, their wide band gap energy and fast charge recombination limit their practical applications. So far, various approaches, such as noble metal incorporation, metal oxide coupling, and the design of Z-scheme photocatalyst systems, among others, have been explored to enhance the lifetime of photogenerated charge carriers in ZnO and TiO2. In this study, a novel TiO2-Ag-ZnO nanocomposite photocatalyst has been successfully synthesized by a combination of wet chemistry, photochemistry, and plasma-based processes. Simple spin coating of ZnO thin films was coupled with subsequent photodeposition of metallic Ag nanoparticles (NPs). Afterward, well-uniform TiO2 NPs (roughly 18 nm) were deposited on this unique Ag-ZnO surface via a gas cluster aggregation source (GAS) process. The results showed that the activity of the ZnO photocatalyst under mixed UV-visible light was significantly increased by the TiO2 and Ag contributions. A single mechanism to be responsible for the photocatalytic activity can be excluded. Instead, a critical assessment of the possible mechanisms corresponding to the different interfaces present at the TiO2-Ag-ZnO surface including a Z–scheme is provided.

The role of interfaces and morphology on silver diffusion in hard coatings

One of the main approaches to increase the tool lifetime during dry machining of “hard-to-machine” aerospace alloys is self-lubrication by the incorporation of noble metals in hard matrixes with good mechanical and diffusion barrier properties. In this paper, the diffusion of an Ag-rich layer sandwiched between two layers of either TiN or TiSiN is studied by transmission electron microscopy and in situ Rutherford backscattering spectrometry. The layer stacks were subjected to annealing treatments at 600 °C and 800 °C for 2 hours. Three processes were found to control the diffusion of silver: the morphology of the “sandwich” layers, the formation of small voids in the involved interfaces and the sublimation of Ag in the surface at temperatures near the melting point. The study revealed that the dense TiSiN matrix allowed a significantly better control of Ag diffusion than the more open TiN matrix.

Noble metals (Pd, Ag, Pt, and Au) doped bismuth oxybromide photocatalysts for improved visible light-driven catalytic activity for the degradation of phenol

The doping of noble metals onto the semiconductor metal oxides has a great impact on the intrinsic properties of the materials. This present work reports the synthesis of noble metals doped BiOBr microsphere by a solvothermal method. The various characteristic findings reveal the effective incorporation of Pd, Ag, Pt, and Au onto the BiOBr and the performance of synthesized samples was test for the degradation of phenol over visible light. The Pd-doped BiOBr material showed enhanced phenol degradation efficacy, which is ∼4-fold greater than pure BiOBr. This improved activity was on reason of good photon absorption, lower recombination rate, and higher surface area facilitated by surface plasmon resonance. Moreover, Pd-doped BiOBr sample displayed good reusability and stability after 3 cycles of run. A plausible charge transfer mechanism for phenol degradation is disclosed in detail over Pd-doped BiOBr sample. Our findings disclose that the incorporation of noble metal as the electron trap is a feasible approach to enhance visible light activity of BiOBr photocatalyst used in phenol degradation. This work represents new vision interested in the outline and development of noble metal doped semiconductor metal oxides as a visible light material for the elimination of colorless toxins from untreated wastewater.

Heterostructure engineering and ultralow Pt-loaded multicomponent nanocage for efficient electrocatalytic oxygen evolution

Developing highly efficient electrocatalysts based on appropriate heterojunction engineering and electronic structure modification for the oxygen evolution reaction (OER) has been extensively recognized as an effective approach to increase the efficiency of water splitting. Herein, ultralow Pt-loaded (1 %) NiCoFeP@NiCoFe-PBA hollow nanocages with well-defined heterointerfaces and modified electronic environment are successfully fabricated. As expected, the obtained Pt-NiCoFeP@NiCoFe-PBA exhibits outstanding performance with a low overpotential of 255 mV at 10 mA cm−2 and a small Tafel slope of 57.2 mV dec-1. More specifically, the highly open three-dimensional structure, exquisite interior voids and abundant surface defects endow Pt-NiCoFeP@NiCoFe-PBA nanocages with more electrochemical active sites. Meanwhile, experimental results and mechanism studies also reveal that the construction of heterogeneous interfaces as well as incorporation of noble metals could readily induce strong synergistic effects and significantly tailor electronic configurations to optimize the binding energy of the intermediates, thereby achieving prominent OER performance.

X-ray absorption spectroscopic study of Pd2+ on Ni site in pentlandite

Abstract Norilsk sulfide ores are one of the largest known sources of Pd on Earth. Palladium in these ores is presented in platinum-group minerals (PGM) and base metal sulfides (BMS), especially in pentlandite [(Fe,Ni)9S8]. Although several studies demonstrated high concentrations along with heterogeneous distribution of Pd in pentlandites from Norilsk, the form of Pd in pentlandite has not been established. Here, we provide the first evidence for Pd incorporation in the structure of pentlandite from Norilsk ores using X-ray absorption near edge structure (XANES) spectroscopy, synchrotron-based micro-X-ray fluorescence (μXRF), and electron backscatter diffraction (EBSD). We present the first ever measured XANES spectra of Pd in pentlandite and atokite [(Pd,Pt)3Sn] as well as in other common Pd minerals. Divalent Pd in pentlandite was detected by XANES. The Pd spectra in pentlandite show no similarities with Pd spectra in PGM, metallic Pd, PdS, PdCl2, and PdSO4 which signifies that Pd incorporates into the lattice of pentlandite. Substitution of Ni by Pd in the lattice of pentlandite is supported by negative correlations shown by μXRF and electron probe microanalysis (EPMA) and complies with the previous studies. The additional EBSD study demonstrates a resemblance in cell parameters of the Pd-rich and Pd-poor parts of the pentlandite grains and reflects that Pd incorporation into the pentlandite structure does not imply any notable structure distortion. The combination of analytical techniques used in the present study demonstrates the great potential of these methods for understanding the mechanisms of noble metal incorporation into ore minerals.

Adsorption of NH3 on Monolayer SiC Doped with Noble Metals: A First-Principles Study

We investigates the effect of noble metals (Ag, Au, and Pt) doped SiC for the adsorption behavior of NH3 gas by using the first-principles method. The influence of NH3 gas and noble metals upon the electronic characteristics of SiC structures are explored. In comparison to the pristine structure, the doped SiC structures reveal significant changes in electronic characteristics, and the adsorption capacity is greatly improved due to incorporation of noble metals. Thus, the sensitivity is enhanced in contrast to the pristine structure. Our results show that the Pt-doped SiC might be a useful candidate for developing sensitive NH3 gas detectors.

Behavioral remodeling of perovskite BiFeO3 by Ag-doping strategies for enhanced and ppb level acetone sensing performance: An advanced enlightenment for selectivity and sensing mechanism

Improvement of the catalytic reactions on the sensing surface or modulation of charge carriers of the sensing material are the most favorable ways to enhance sensing performance for a chemi-resistive sensor. Incorporation of noble metals can enhance the sensing features of chemi-resistive type sensors by synergistic effect of chemical (catalytic effect) or electronic (tuning of charge carrier concentration) sensitization. In this view, the present study performs a behavioral remodeling of sol-gel synthesized BiFeO3 (BFO) chemi-resistive sensor by low-cost Ag-doping strategies to enhance its acetone sensing performance with removal of irreversibility. The Ag-doped BFO (Bi0.9Ag0.1FeO3) sensor can selectively detect acetone vapor (Rcross = RAcetone/RXylene: 17; RAcetone/RHexane: 08; RAcetone/RToluene: 05; RAcetone/RMethanol: 2.5; RAcetone/REthanol: 2.2) operating at 350°C. Ag-BFO sample shows an enhancement (1.8-fold) in response (R∼22) value with 5-fold faster response time (τres∼8s) for 50 ppm acetone exposure compared to pristine BFO (R∼12, τres∼45s). Excellent repeatability over 09 loop character with high degree of long-term stability for 300 days and ppb level detection (500 ppb) favorable to biomarker recognition for critical diseases confirms the commercial viability of Ag-doped BFO sample. The ion-dipole (highest interaction energy, Ei-d = -1.02 × 10−19 J for acetone)/dipole-dipole coupling, the ferroelectric nature of BiFeO3 and sensitization effect (by metallic Ag-phase) has paved the path for revealing the selectivity and sensing mechanism for the prepared prototype in an innovative way.

The effect of doping MoSe2 by clusters of noble metals on its adsorption for NH3

The development of industrial activities is associated with negative impacts on the quality of the environment including emission of hazardous gases. Therefore, it is critical to produce sensitive and selective gas detectors in order to monitor and maintain its good quality. This work investigates the effect of noble metal doping of MoSe2 on its adsorption of ammonia (NH3) gas. Pristine and noble metal doped MoSe2 structures are examined computationally using density functional theory (DFT). Clusters of timers of each Pt, Au, and Ag along with their combination are utilized for doping. The influence of doping MoSe2 structure on its adsorption energy and distance of NH3 gas, density of states (DOS), charge transfer between NH3 and the MoSe2 structures, and band structure is explored. When compared to the pristine structure, the doped MoSe2 structures reveal significant changes in electronic characteristics that are reflected on the DOS and band structures. New energy bands have evolved near to the Fermi level because of modifying the MoSe2 structure. The adsorption capacity of the doped structures is greatly enhanced due to incorporation of noble metals. Herein, the magnitude of adsorption energy increases and the adsorption distance deceases for NH3 gas. Consequently, the sensitivity is improved in comparison to the pristine structure. This study shows that noble metal doping of MoSe2 by clusters of trimers can be a useful approach for developing sensitive NH3 gas detectors.

Realization of ppb-level acetone detection using noble metals (Au, Pd, Pt) nanoparticles loaded GO FET sensors with simultaneous back-gate effect

In the current study, graphene oxide (GO), uniformly loaded with different noble metal nanoparticles (Au, Pd and Pt) were synthesized by spray coating technique and implemented in field effect transistor (FET) sensors. The morphology, structure, composition and electronic properties of the synthesized materials were characterized. The sensing results indicated that the incorporation of noble metals can greatly enhance the VOC sensing properties of a few layers of GO by using their chemical and electrical sensitization effect. At optimized gate potential, GO FET exhibited outstanding sensing properties at low operating temperature i.e. 50 °C. Specifically, the FET sensor based on Pd loaded GO exhibited the highest response, quickest response/recovery (37 s/91 s) characteristics, best selectivity and low operating temperature towards low concentration of acetone. Almost five times higher sensitivity towards acetone (400 ppb) was achieved in Pd/GO as compared to the pure GO channel nanoparticles under a suitable back gate bias.

Studies on the silver incorporated titania aerogel nanostructure as a photoanode in quasi solid dye- sensitized solar cells

Dye-sensitized solar cells (DSSC) have a significant impact on photovoltaic technology because of their quick, low-cost manufacture, light weight, and high power conversion efficiency (PCE). Numerous research works were undergone on different titania nanostructure used as photoanode in DSSC. High surface area titania nanoarchitecture has effective for more dye absorption to improve the cell performance. Titania aerogels have a high specific surface area and high porosity compared to other titania nanostructures. Incorporation of noble metals into titania aerogel enhanced PCE. In noble metals, silver has promising material because of its cost-effective, less ohmic resistance etc. compared to Au. In this work, we prepared silver doped titania aerogel and studied its photovoltaic performance in the quasi solid DSSC performance. Silver-incorporated titania aerogel was synthesized by the facile sol–gel route. Structural, optical, photovoltaic properties and cell stability of a prepared photoanode material were measured. PXRD revealed that the anatase phase is retained after the incorporation of silver. HRSEM images and EDS spectra confirmed the interconnecting network of titania aerogel and the presence of silver respectively. Due to the Localized Surface Plasmonic Resonance (LSPR) effect, the absorption spectra of the composite exhibited a red-shift around 650 nm. PL spectra showed the decreasing intensity in composites which is the evidence of suppressing electron-hole recombination and improving electron injection. The incorporation of silver has improved the photon absorption capability of the photoanode tends to enhance photocurrent density as well as PCE of QS-DSSC.

Plasmonic metallic silver induced Bi2WO6/TiO2 ternary junction towards the photocatalytic, electrochemical OER/HER, antibacterial and sensing applications

The plasmonic metal-induced Bi2WO6/TiO2 ternary composite with unique electronic and structural properties was synthesized via a hydrothermal and chemical reduction route for sustainable energy and environmental remediation. The obtained Bi2WO6/TiO2-Ag (BWTA) exhibited a tremendous catalytic activity for Rhodamine B photodegradation (0.947 × 10-2 min−1) than those of sole TiO2 and Bi2WO6 specimens. The radical trapping experiment discloses that superoxide .O2− and holes (h+) are the cardinal active species in the photocatalytic system. Further, recycling experiment was conducted to elucidate the stability of the photocatalyst. BWTA2.0 was able to produce 2.1330 mA/cm2 of current density for oxygen evolution reaction and −1.5003 mA/cm2 for hydrogen evolution reaction, which is much higher than those of other specimens. Besides, electrochemical detection of dopamine (DA) was performed through cyclic voltammetry; results showed that the ternary composite had better electrocatalytic activity for DA detection owing to the synergistic effects of noble metal incorporation into the semiconductor. Also, the antibacterial potential of the specimens was explored against Escherichia coli through the well-diffusion method. In terms of experimental results, a possible mechanism of ternary composite is thoroughly elucidated. Thus, this work validates that, plasmonic induced ternary composite has a great prospect for photocatalytic, electrochemical, sensing, and antibacterial applications.

Solar-Powered Photodegradation of Pollutant Dyes Using Silver-Embedded Porous TiO2 Nanofibers.

Titanium dioxide (TiO2) nanomaterials have been ubiquitously investigated as a photocatalyst for organic contaminant treatment in wastewater due to their exemplary semiconductor properties. However, their huge band gap remains a barrier for visible light absorption, limiting their utility in practical applications. The incorporation of noble metals in the TiO2 scaffold would help mitigate the problem via plasmonic resonance enhancements. Silver (Ag) is the chosen noble metal as it is relatively cheap and has great plasmonic effects. In this study, the use of electrospun Ag-embedded TiO2 nanofibers as a photocatalyst is shown to be effective in decomposing rhodamine B and methyl orange dyes under a solar simulator in 3 h, which is more efficacious as opposed to pristine TiO2 nanofibers. This showcases the potential of a simple and economic wastewater treatment system for the removal of organic pollutants.

Activating Iron Based Materials for Overall Electrochemical Water Splitting via the Incorporation of Noble Metals.

Although the presence of iron in mixed metal oxide based catalysts has shown significant performance improvement in the oxygen evolution reaction (OER), iron oxides themselves demonstrate much poorer activity. In this study, we investigate improving the performance of iron catalysts via surface decoration with gold or platinum for not only the OER but also the hydrogen evolution reaction (HER) for overall water splitting in an alkaline electrolyte. Two types of iron catalysts were synthesised, iron nanocubes and iron oxide via electrochemical deposition methods which were decorated with either Au or Pt via galvanic replacement. It was found that the presence of Au significantly enhanced the OER performance of iron oxide and the HER performance of iron nanocubes. The presence of Pt resulted in moderate improvement in the OER but significant improvement for the HER but did not surpass the performance of gold decorated iron nanocubes. This indicates that the speciation of the iron catalyst and the decorating metal was important for tuning the activity to the OER and the HER. For the OER, the formation of iron oxide/Au interfaces was determined to be an important component for high activity whereas the metallic nature of metal decorated iron nanocubes was important for the HER. Therefore, iron based catalysts can be modified to demonstrate bifunctional behaviour for overall water splitting via the inclusion of gold nanoparticles.

Functionalization of zirconium-based metal–organic frameworks for gas sensing applications

The functionalization and incorporation of noble metals in metal–organic frameworks have been widely used as efficient methods to enhance their applicability. Herein, a sulfone-functionalized Zr-MOF framework labeled Zr–BPDC–SO2 (BPDC–SO2 =dibenzo[b,d]-thiophene-3,7-dicarboxylate 5,5-dioxide) and its Pd-embedded composite were efficiently synthesized by adjusting their functional groups. The obtained compounds were characterized to assess their potential for gas sensing applications. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, specific surface area measurements, and thermogravimetric analysis were employed to characterize the new sensor materials. The gas sensing properties of the novel functionalized sensor materials were systematically investigated under various temperature, concentration, and gas type conditions. Owing to the strong hydrogen bonds of the sulfonyl groups and Zr6 clusters in the framework with the hydroxyl groups of ethanol, Zr–BPDC–SO2 emerged as an effective sensor for ethanol detection. In addition, Pd@Zr–BPDC–SO2 exhibited efficient hydrogen sensing performance, in terms of sensor dynamics and response. More importantly, the material showed a higher sensing response to hydrogen than to other gases, highlighting the important role of Pd in the Zr-MOF-based hydrogen sensor. The results of the sensing tests carried out in this study highlight the promising potential of the present materials for practical gas monitoring applications.

Irreversible accumulated SERS behavior of the molecule-linked silver and silver-doped titanium dioxide hybrid system

In recent years, surface-enhanced Raman scattering (SERS) of a molecule/metal–semiconductor hybrid system has attracted considerable interest and regarded as the synergetic contribution of the electromagnetic and chemical enhancements from the incorporation of noble metal into semiconductor nanomaterials. However, the underlying mechanism is still to be revealed in detail. Herein, we report an irreversible accumulated SERS behavior induced by near-infrared (NIR) light irradiating on a 4-mercaptobenzoic acid linked with silver and silver-doped titanium dioxide (4MBA/Ag/Ag-doped TiO2) hybrid system. With increasing irradiation time, the SERS intensity of 4MBA shows an irreversible exponential increase, and the Raman signal of the Ag/Ag-doped TiO2 substrate displays an exponential decrease. A microscopic understanding of the time-dependent SERS behavior is derived based on the microanalysis of the Ag/Ag-doped TiO2 nanostructure and the molecular dynamics, which is attributed to three factors: (1) higher crystallinity of Ag/Ag-doped TiO2 substrate; (2) photo-induced charge transfer; (3) charge-induced molecular reorientation.