Immobilization Of AuNPs Research Articles

Gold nanoparticles supported on alumina grafted N-doped RGO: A green catalyst for the catalytic degradation of organic dyes and deprotection of oximes

An environmentally benign synthetic protocol for the preparation of gold supported N-doped TRGO-modified γ-alumina has been reported. The research focused on the use of different strategies for reduction of GO using natural as well as chemical reducing agents. Fresh tulsi and neem leaf extract were used for bio-reduction of GO, while hydrazine hydrate and sodium borohydride were used for the chemical reduction of GO to obtain RGO. The preliminary analysis from FT-IR and BET surface area authenticated that tulsi leaf extract was the best reducing agent among others for the preparation of RGO. TRGO (tulsi leaf extract reduced graphene oxide) obtained from the reduction of GO via tulsi leaf extract was doped with nitrogen to get N-doped TRGO followed by grafting with γ-Al2O3 and immobilization of Au NPs to get the desired catalyst. The developed catalyst was later examined via different characterization techniques. Further, the synthesized catalyst shows great potential for application in degradation of various dyes and oxidative deprotection of oximes. Nitrogen doping as well as the higher specific surface area of the catalyst were two key parameters influencing the higher catalytic performance of Au@NTRGO-γ-Al2O3. The rational strategy exhibited in the present work provides new insights into the development of green, efficient and sustainable catalysts for different organic transformations.

Fe‐doped MoS2@AuNPs Grown on Carbon Cloth for Efficient SERS Detection and Photo/photo‐Fenton Degradation of Fungicides

AbstractA composite CC/Fe−MoS2@Au composed of gold nanoparticles in‐situ grown on Fe‐doped MoS2 anchored on carbon cloth (CC) was prepared for SERS detection and photo/photo‐Fenton degradation of fungi pesticides. Flower‐like MoS2 grown on CC provides large surface area for in‐situ reduction and immobilization of AuNPs, generating high SERS enhancement effect. Fe‐doping improves MoS2’s SERS activity and photocatalysis and endows the composite with Fenton degradation ability due to the coexistence of Fe3+/Fe2+ confirmed by XPS. Owing to their synergy, the CC/Fe−MoS2@Au can achieve the SERS detection of fungicide crystal violet (CV) and malachite green (MG) with detection limits of 0.1 nM and 10 nM, respectively. The CC endows it flexibility for fungicide sensing on irregular surface, such as fish skin with a LOD of 10−7 M for MG. The composite displayed multimode degradation ability for fungicides: 70 % of 10−5 M CV could be degraded after 75 min photocatalytic degradation by CC/Fe−MoS2@Au under natural light, while it increases to 85 % in the presence of H2O2 through a photo‐Fenton reaction. The synergy mechanism of these components for fungicide degradation were discussed. Such flexible multifunctional composite has great value in SERS analysis, environmental monitoring and remediation.

Ultrasensitive Electrochemiluminescence Immunosensor for Bladder Marker Human Complement Factor H-Related Protein Detection.

The development of noninvasive and sensitive detection methods for the early diagnosis and monitoring of bladder cancer is critical but challenging. Herein, an ultrasensitive electrochemiluminescence (ECL) immunosensor that uses Ru(bpy)32+-metal-organic framework (Ru-MOF) nanospheres and a DNA tetrahedral (TDN) probe was established for bladder cancer marker complement factor H-related protein (CFHR1) detection. The synthesized Ru(bpy)32+-metal-organic frameworks (Ru-MOFs) served as a linked substrate for immobilization of AuNPs and antibody (Ab2) to prepare the ECL signal probe (Ru-MOF@AuNPs-Ab2), exhibiting a stable and strengthened ECL emission. At the same time, the inherent advantages of TDN probes on the electrode as the capture probe (TDN-Ab1) improve the accessibility of targets to probes. In the presence of CFHR1, the signal probe Ru-MOF@AuNPs-Ab2 was modified on the electrode through immune binding, thereby obtaining an outstanding ECL signal. As expected, the developed ECL immunosensor exhibited splendid performance for CFHR1 detection in the range of 0.1 fg/mL to 10 pg/mL with a quite low detection limit of 0.069 fg/mL. By using the proposed strategy to detect CFHR1 from urine, it showed acceptable accuracy, which can effectively distinguish between bladder cancer patients and healthy samples. This work contributes to a novel, noninvasive, and accurate method for early clinical diagnosis of bladder cancer.

MXene-based gold nanoparticle catalyst with high activity and stability for 4-nitrophenol reduction

Catalytic reduction is considered an effective method for converting organic compounds. However, a lack of efficient catalysts has hindered its practical application. Herein, the cationic poly(diallyldimethylammonium chloride) (PDDA) was used as a stabilizer to synthesize a novel MXene-supported gold nanoparticles composite by electrostatic interaction and self-reduction methods. As a stabilizer bridging transition metal carbides (MXene, Ti3C2Tx) and gold nanoparticles (AuNPs), the PDDA polymer provided rich binding sites for AuNPs immobilization, resulting in uniform distribution of AuNPs on MXene nanosheet and efficient control over their particle size. The synergistic effects of the composite catalyst improved its catalytic activity towards 4-nitrophenol (4-NP) reduction, and the normalized rate constant (K) was high up to 2.65 × 10−2 s−1. Notably, the composite catalyst also showed high stability due to the protection of PDDA, and the conversion efficiency for 4-NP was high up to 94.85% after five recycles. Our findings presented here not only are potential for catalytic applications, but also provide a foundation for the development of efficient MXene-based catalysts.

Gold Nanoparticles Immobilized in Porous Aromatic Frameworks with Abundant Metal Anchoring Sites as Heterogeneous Nanocatalysts.

Porous aromatic frameworks (PAFs) with rich metal coordination sites are highly effective support materials for gold nanoparticles (AuNPs), which would not only prevent AuNPs agglomeration but also facilitate mass transfer during the catalytic process. In this work, PAF-160, -161, and -162 bearing diphosphine units are synthesized via the Friedel-Crafts alkylation reaction to act as efficient platforms for AuNPs immobilization. These PAFs possess high surface areas (up to 655 m2 g-1) together with excellent stabilities, and the different linkage lengths between P centers allow more scattered and accessible sites for gold coordination. In the resultant Au-PAFs, AuNPs with uniform sizes are stabilized dispersedly. The catalytic performances of these Au-PAFs are monitored by the reduction of 4-nitrophenol (4-NP), and all materials exhibit excellent catalytic activities on the reduction of 4-NP, especially Au-PAF-162 with the apparent rate constant (kapp) up to 0.019 s-1. Additionally, the reductions of various nitroarenes with different functional groups are explored and all Au-PAFs can convert most nitroaromatic derivatives to the corresponding arylamines with high conversions of 99%, in which the reaction mechanism is also proposed. Furthermore, a continuous catalytic device with Au-PAF-160 catalyst is explored, and Au-PAF-160 can convert 1-chloro-4-nitrobenzene, 2,6-dichoronitrobenzene and 1-chloro-2,4-dinitrobenzene into the corresponding amines in sequence in the continuous flow catalytic experiments. This work has enriched the variety of porous materials for noble metal immobilization and promotes their applications in heterogeneous catalysis.

Role of Defects of Carbon Nanomaterials in the Detection of Ovarian Cancer Cells in Label-Free Electrochemical Immunosensors.

Developing label-free immunosensors to detect ovarian cancer (OC) by cancer antigen (CA125) is essential to improving diagnosis and protecting women from life-threatening diseases. Four types of carbon nanomaterials, such as multi-wall carbon nanotubes (MWCNTs), vapor-grown carbon fiber (VGCFs), graphite KS4, and carbon black super P (SP), have been treated with acids to prepare a carbon nanomaterial/gold (Au) nanocomposite. The AuNPs@carbon nanocomposite was electrochemically deposited on a glassy carbon electrode (GCE) to serve as a substrate to fabricate a label-free immunosensor for the detection of CA125. Among the four AuNPs@carbon composite, the AuNPs@MWCNTs-based sensor exhibited a high sensitivity of 0.001 µg/mL for the biomarker CA125 through the square wave voltammetry (SWV) technique. The high conductivity and surface area of MWCNTs supported the immobilization of AuNPs. Moreover, the carboxylic (COO-) functional groups in MWCNT improved to a higher quantity after the acid treatment, which served as an excellent support for the fabrication of electrochemical biosensors. The present method aims to explore an environmentally friendly synthesis of a layer-by-layer (LBL) assembly of AuNPs@carbon nanomaterials electrochemical immunoassay to CA125 in a clinical diagnosis at a low cost and proved feasible for point-of-care diagnosis.

Green synthesis of reduced graphene oxide/chitosan/gold nanoparticles composites and their catalytic activity for reduction of 4-nitrophenol

Gold nanoparticles (AuNPs) have attracted extensive attention in the past few years due to their unique properties and great potential application in catalysis. However, the application of AuNPs remains a significant challenge due to the lack of high efficiency and stability caused by aggregation. Immobilization of AuNPs on appropriate support shows promising results in avoiding aggregation and improving catalytic activity. In this work, reduced graphene oxide/chitosan/gold nanoparticles (rGO/CHS/AuNPs) composites were prepared using chitosan with different molecular weights (MW) as a reducing agent and stabilizer, and characterized by FT-IR, XRD, XPS, SEM, FESEM, EDS, TEM, HRTEM, and TGA. The preparation conditions of rGO/CHS/AuNPs composites, including chitosan MW, CHS/GO mass ratio, reaction temperature and time, and HAuCl4 concentration were investigated in detail. The results indicated that reduction activity of chitosan for GO increased with the decrease of chitosan MW. The C/O ratio of rGO reduced by low molecular weight chitosan (LMWC) with viscosity-average molecular weight (Mv) of 21 kDa was 6.34. Small spherical AuNPs were uniformly immobilized on the rGO surface. The particle size of AuNPs increased from 9.29 to 13.03 nm as chitosan MW decreased from 465 to 21 kDa. The rGO/CHS/AuNPs showed good catalytic activity for the reduction of 4-NP in the presence of NaBH4. The catalytic activity of rGO/CHS/AuNPs was closely related to chitosan MW. rGO/CHS/AuNPs synthesized by LMWC with Mv of 21 kDa showed the highest kinetic rate constant of 0.2067 min−1. The results of this experimental study could be useful in the development of effective catalysts for the reduction of aromatic nitro compounds.

Immobilization of Gold Nanoparticles in Spherical Polymer Brushes Observed by Small-Angle X-ray Scattering.

Nanosized gold nanoparticles (AuNPs) are of great interest in areas such as catalysts or imaging but are easy to aggregate due to high surface activity. To stabilize AuNPs, two approaches were employed to immobilize AuNPs in spherical polymer brushes (SPBs), namely, the in situ preparation of AuNPs within the brush layer of SPBs and external addition of preprepared citrate-capped AuNPs. The distribution and stability of AuNPs in SPBs were studied by small-angle X-ray scattering (SAXS). SAXS results demonstrated that the in situ-prepared AuNPs were mainly located on the inner layer and their amount decreased from inside to outside. In the case of external addition of preprepared AuNPs, the cationic SPB showed obvious immobilization, while almost no AuNPs were immobilized in the anionic SPB. The stable immobilization of the AuNPs in SPBs was the result of multiple interactions including complexation and electrostatic interaction. SAXS was validated to be a distinctive and powerful characterization method to provide theoretical guidance for the stable immobilization of AuNPs.

Benzil alkol oksidasyonu için heterojen katalizör olarak altın nanoparçacık immobilize edilmiş gözenekli manganez oksit mikroküreler

A heterogenous catalyst in the form of Au nanoparticles (Au NPs) immobilized porous manganese oxide (Mn5O8) microspheres was synthesized. The sol-gel templating method was used for the synthesis of Mn5O8 microspheres. The heterogenous catalyst showed good performance when compared with similar catalysts in the oxidation of benzyl alcohol. The heterogenous catalyst (Au@Mn5O8) obtained by the immobilization of Au NPs on Mn5O8 microspheres performed 99.4% of benzyl alcohol conversion and 100 % of benzaldehyde formation yield. Also the heterogenous catalyst showed a good stability and agglomeration resistance in the reusabilty experiments. Au@Mn5O8 microspheres could be reused up to 5 times without remarkable loss in the catalytic activity.

In situ decoration of Au NPs over polydopamine encapsulated GO/Fe3O4 nanoparticles as a recyclable nanocatalyst for the reduction of nitroarenes

A new and efficient catalyst has been designed and prepared via in situ immobilization of Au NPs fabricated polydopamine (PDA)-shelled Fe3O4 nanoparticle anchored over graphene oxide (GO) (GO/Fe3O4@PDA/Au). This novel, architecturally interesting magnetic nanocomposite was fully characterized using different analytical techniques such as Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, elemental mapping, Transmission Electron Microscopy, Fourier Transformed Infrared Spectroscopy, X-ray Diffraction and Inductively Coupled Plasma-Atomic Electron Spectroscopy. Catalytic activity of this material was successfully explored in the reduction of nitroarenes to their corresponding substituted anilines, using NaBH4 as reducing agent at ambient conditions. The most significant merits for this protocol were smooth and clean catalysis at room temperature with excellent productivity, sustainable conditions, ease of separation of catalyst from the reaction mixture by using a magnetic bar and most importantly reusability of the catalyst at least 8 times without any pre-activation, minimum loss of activity and considerable leaching.

Construction of hydrophilic N, O-rich carboxylated triazine-covalent organic frameworks for the application in selective simultaneous electrochemical detection

In this study, we strategically designed a hydrophilic N, O-rich carboxylated triazine- covalent organic frameworks (ACOF-TaTp) for the application in selective simultaneous electrochemical detection of mixed chemical compounds with closing oxidation potentials. The ACOF-TaTp was firstly constructed with high surface area and hydrophilicity by 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 1,3,5-triformylphloroglucinol followed with carboxylation by sodium chloroacetate. Characterizations demonstrated the high surface area and rich N, O-electron donors of ACOF-TaTp facilitated the high dispersion and immobilization of AuNPs on it via electrostatic interactions. Based on their chemical properties, Gallic acid (GA) and uric acid (UA) were selected as model compounds for the test and the result showed their closing oxidation peaks could be clearly separated by ACOF-TaTp, which could be ascribed to its high surface area and stronger affinity to GA than to UA via H-bonding. The constructed sensor AuNPs@ ACOF-TaTp/GCE exhibited high selectivity and sensitivity in the simultaneous determination of GA and UA with a wide linear response in the range of 1–175 μM for GA and 1–150 μM for UA and detection limit of 0.19 μM and 0.25 μM respectively. This work paves a way for strategical design of functionalized COFs for simultaneous electrochemical sensing.

Alginate modified magnetic nanoparticles to immobilization of gold nanoparticles as an efficient magnetic nanocatalyst for reduction of 4-nitrophenol in water

This article displays synthesis of gold nanoparticles (Au NPs) decorated on sodium alginate (Alg) covered magnetite (Fe3O4@Alg-AuNPs) nanocomposite. Sodium alginate shell as a natural anionic polysaccharide on Fe3O4 microparticles core acted as a stabilizing agent for immobilization of Au NPs. Its catalytic performance was tested in the reduction of 4-nitrophenol to 4-aminophenol. The structural features of the synthesized nanocatalyst were investigated by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission electron microscopy (TEM), Energy Dispersive X-Ray Analysis (EDX), and Vibrating-sample magnetometer (VSM) studies. The catalytic activity of the material in the reduction process was quantitatively monitored using Ultraviolet–visible (UV–Vis) spectroscopy and it resulted excellent yields (99%) at short reaction time (1.5–4 min) in aqueous media at room temperature using very low catalyst load (1–3 mg). The kinetics study was also performed which afforded a good rate constant. Additionally, the catalyst showed high reproducibility as was easily retrievable and recoverable without noticeable loss in its catalytic activity.

Development of Electrochemical Sensor Based on Thiolated Calixarene-Functionalized Gold Nanoparticles for the Selective Recognition of Anthracene

In this work, an electrochemical sensor for anthracene detection was constructed based on a modified electrode consisting of thiolated calixarene (TC4)-functionalized gold nanoparticles (AuNPs) and electrochemically reduced graphene oxide (ERGO). Firstly, graphene oxide GO) was reduced on screen printed carbon electrodes (SPCE), followed by the immobilization of AuNPs and TC4 through a self-assembly process to form TC4/AuNPs/ERGO-SPCE. The molecules’ structure was characterized using FTIR and Raman spectroscopy, the sample’s morphology and topology were characterized using Field Emission Scanning Electron Microscopy (FESEM), High Resolution Transmission Electron Microscopy (HRTEM) and electrochemical performance of developed sensor was characterized using electrochemical method. Owing to the outstanding supramolecular recognition of anthracene by TC4, the target analyte was detected accurately with a linear range of 1- $7~\mu \text{M}$ and limit of detection down to $0.0625~\mu \text{M}$ (S/N = 3). Additionally, the sensor was acknowledged for its excellent anti-interference properties in the presence of organic compounds as well as inorganic metal ions. The proposed sensor also yielded comparable results to conventional HPLC method, with a satisfactory recovery of 92–98% in environmental samples.

Label-free electrochemical immunosensor for the detection of prostate specific antigen based three-dimensional Au nanoparticles/MoS2-graphene aerogels composite

In the present work, a label-free prostate specific antigen (PSA) electrochemical immunosnesor was constructed based on Au nanoparticles/MoS2-graphene aerogels nanocomposite (AuNPs/MoS2-GAs) as sensing platform. MoS2-GAs composite with porous network structure provided large specific area for the immobilization of AuNPs, which further improved the loading of PSA antibodies. In addition, the AuNPs/MoS2-GAs composite has good conductivity, which could accelerate the electron transport of the electrode interface. Based on these advantages of AuNPs/MoS2-GAs material, the prepared immunosensor exhibited wide linearity in the range of 0.00001–50 ng mL−1 and a low detection limit of 0.003 pg mL−1. The immunosensor also exhibited acceptable stability, good selectivity, and reproducibility. Moreover, when applied to analyze PSA in human serum, the immunosensor obtained good recovervries, indicating the method shows a promising application for early diagnosis of PSA.

Highly selective reduction of nitroarenes with gold nano-catalysts immobilized in porous aromatic frameworks

Abstract Gold nanoparticles (AuNPs) are highly activated nano-catalysts because of their significantly high surface-to-volume ratio. However, the agglomerative trend of NPs in the solutions causes reduced catalytic activity and inhibits their practical applications. Porous aromatic frameworks (PAFs) with high surface area and enduring stability are ideal support materials for AuNPs immobilization, and their diverse functionalized frameworks would greatly facilitate AuNPs incorporation, thus can be applied as excellent heterogeneous catalysts. By selecting triphenylphosphine and diphenyl-2-pyridylphosphine as monomers, which are the most preferential species to prepare ligand-protected AuNPs, PAF-95 and PAF-96 with high surface areas as well as uniform micropores were successfully synthesized with anhydrous FeCl3 catalysts. With the potential coordination sites of phosphine unit and pyridyl group in PAFs’ skeletons, NPs aggregation was suppressed and AuNPs were evenly dispersed in the resultant Au-PAFs. Benefiting from the high surface area of PAFs and uniform AuNPs incorporation, Au-PAFs nano-catalysts exhibited highly efficient and selective catalytic performance for the reduction of nitroarenes. Meanwhile, their valuable stability enabled good recyclability: retaining high catalytic activities after five cycles.

Fabrication of an electrochemical sensing platform based on hydrophilic carbon/gold nanoparticles composite

A simple, economical, and environmentally friendly strategy for the one-pot preparation of a nanocomposite made up of gold nanoparticles and Electrogenerated Hydrophilic Carbon material (EHC), is reported in this work. The EHC material works itself as the reducing agent and conductive carbon material support. The formation of AuNPs was confirmed by UV–visible spectroscopy and transmission electron microscopy. It was demonstrated that after the nanocomposite immobilization on a substrate, the EHC material can be easily removed due to its outstanding solubility in water. This procedure was exemplified for the modification of a glassy carbon electrode, resulting in a bare AuNPs/GC electrode. The cyclic voltammetry was used to evaluate the effectiveness of AuNPs immobilization on the electrode and to track the dependence of the electroactive surface area and Au loading with the reaction mixture composition (HAuCl4/EHC). The potential of the AuNPs and nanocomposite-modified electrodes as sensor platforms for medical and biological applications was exemplified by their performance for the oxygen reduction reaction in a phosphate buffer saline solution.

Self-assembled bio-inspired Au/CeO2 nano-composites for visible white LED light irradiated photocatalysis

In this study, plasmonic PDA@Au/CeO2 composites were produced by a self-assembled redox approach. The morphologies, chemical compositions, and optical properties of the composites were investigated. The obtained results showed that the immobilization of Au NPs with good localized surface plasmon resonance (LSPR) properties together with the formation of CeO2(shell)-Au(core) structure onto polydopamine nanoparticles (PDA NPs, as both reducing and stabilizing template) led to the production of active oxygen vacancies between valance and conduction bands as well as enhanced the visible light absorption of the catalyst. The plasmon sensitized photocurrent stability and photoluminescence behaviors clearly revealed the close Schottky contact between CeO2(shell) and Au(core) which led to the decrease in the band gap of composites. Therefore, the study of the photocatalytic mechanism of composites demonstrated that increased ECB value, reduced band gap, great photoresponsivity, plasmon assisted charge separation/transfer properties, and production of active oxygen vacancies provided a new heterogeneous photocatalyst with reasonable good reusability and stability for efficient decolorization of MB under visible LED light irradiation.

Comparison of the catalytic properties of Au nanoparticles supported on different two-dimensional carriers

Choosing a suitable two-dimensional (2D) nanomaterial as a carrier for noble metals is crucial for improving the catalytic performance and reducing the cost of nanocatalysts. In this study, we used ultrathin porous g-C3N4 nanosheets (g-C3N4-NS) as a carrier with gold nanoparticles (Au NPs) anchored on the surface. The ultrathin g-C3N4-NS was advantageous as a carrier because of its large specific surface area, abundant in-plane holes, and low cost. For comparison, 2D TiO2 nanosheets (NS), graphene oxide (GO) NS, and bulk g-C3N4 (g-C3N4-B) were also tested as carriers for the immobilization of Au NPs. Au NPs supported on different carriers were employed as catalysts for the reduction of 4-nitrophenol. The rate constant was calculated as 16.21 × 10−3 s−1 for the Au/g-C3N4-NS nanocatalyst, which was 11.4 and 42.1 times higher than those for the Au/TiO2 and Au/GO nanocomposites, respectively. Au/g-C3N4-NS exhibited excellent catalytic activity during the conversion of 4-nitrophenol with a turnover frequency of 1648 h−1. The as-prepared Au/g-C3N4-NS nanocatalyst also exhibited good catalytic performance during the reduction of 2-nitrophenol and 3-nitrophenol.

Bio-inspired immobilization of silver and gold on magnetic graphene oxide for rapid catalysis and recyclability

Noble metal nanoparticles have been widely employed for catalysis owing to their remarkable ability to reduce the activation energy of certain reactions. In this work, we followed a bio-inspired strategy to fabricate two magnetic nanocatalysts comprised of gold (AuNPs) and silver (AgNPs) nanoparticles. Magnetic graphene oxide (MGO), synthesized by deposition of Fe3O4 nanoparticles on graphene oxide (GO), was used as the support material. Inspired by the adhesive property of marine mussel, polydopamine (PDA) was used as the organic linker for robust immobilization of AuNPs and AgNPs on MGO surface to produce MGO-PDA@Au and MGO-PDA@Ag, respectively. We employed a wide range of microscopic and spectroscopic techniques such as HRTEM, FESEM, EDS, XPS, XRD, FTIR etc. to characterize the catalytic nanomaterials. The catalytic performances of these as-fabricated catalysts were investigated by monitoring the reductions of methylene blue (MB) and 4-nitrophenol (4-NP) by NaBH4 as model reactions. Thermogravimetric analysis and magnetization tests were also done to study the thermal stability and magnetic properties of the nanocomposites. The reaction rate constants obtained for both nanocomposites were found to be higher than most of the similar investigations reported elsewhere. In addition, we proposed a comparison of the catalytic performances of gold and silver nanoparticles when immobilized on same supporting material. This comparison provides means to have better insights of the factors affecting the catalytic performances of AuNPs and AgNPs along with identifying their selectivity towards specific catalytic applications.

Colorimetric detection of Hg(ii) based on the gold amalgam-triggered reductase mimetic activity in aqueous solution by employing AuNP@MOF nanoparticles.

Although the potential of gold amalgam as a nanoenzyme has been demonstrated, its practical utility has been limited by its low catalytic activity caused by the aggregation of Au nanoparticles (Au NPs). Thus, there is a need to further engineer Au NPs to prevent aggregation and then to achieve higher enzyme activities for the detection of Hg2+ ions. Metal organic frameworks (MOFs), as one kind of promising material, have attracted particular attention due to their unique characteristics of uniform cavities and very high porosity. Herein, a hybrid material of Au nanoparticles and a MOF (AuNP@MOF), constructed by immobilization of Au NPs uniformly on the cavity surface of an iron-5,10,15,20-tetrakis (4-carboxyl)-21H,23H-porphyrin-based MOF (Fe-TCPP-MOF), has been successfully synthesized. Based on Hg2+ ion triggered Au catalysis of methylene blue (MB) reduction, a colorimetric method for highly sensitive and selective detection of Hg2+ ions has been established. The Hg2+ ions were first bound to the Au NP surface to form gold amalgam, and then the catalytic activity of Au NPs was initiated. This detection method showed the advantages of a fast response time, and high sensitivity and selectivity. The response time and the limit of detection were as low as 2 s and 103 pM, respectively, benefiting from the uniform cavities and the large specific surface area of Fe-TCPP-MOF, which ensure: (1) uniform dispersion of the Au NPs on the surface of the cavity; and (2) a higher chance of interaction of mercury and MB owing to the gathering effect of Fe-TCPP-MOF.