CoOOH Nanosheets Research Articles

Structural Regulation of a Multi-Component Co2P2O7-MoN/NC Electrocatalyst for Efficient Oxygen Evolution Reaction.

Realizing efficient and durable non-precious metal-based electrocatalysts for oxygen evolution reaction (OER) still remains a great challenge. Here, a multi-component composite of Co2P2O7-MoN/NC containing pyrophosphate, nitride, and nitrogen-doped carbon is successfully prepared via a facile two-step synthesis method. Combining the structural regulation between the active metal- and non-metal-based species, Co2P2O7-MoN/NC demonstrates superior activity and durability for OER, requiring an overpotential of 278 mV at a current density of 10 mA cm-2, a Tafel slope of 83.3 mV dec-1, and long-term stability over 100 h in an alkaline solution. Post-characterizations reveal that synergistic effect among stable Co2P2O7, partially dissolved MoN, N-doped carbon, and new-formed CoOOH nanosheets enable structural reconstruction, fast charge transfer, and formation of oxygen-containing intermediates, promoting the OER performance significantly. This work provides a promising pathway to tune multi-components to fabricate efficient transition-metal-based electrocatalysts in energy conversion applications.

Integration of Multifunctionality in a Colloidal Self‐Repairing Catalyst for Alkaline Water Electrolysis to Achieve High Activity and Durability

Self‐repairing catalysts are useful for achieving alkaline water electrolyzers with long lifetimes under intermittent operation. However, rational methodologies for designing self‐repairing catalysts have not yet been established. Herein, hybrid cobalt hydroxide nanosheets (Co‐ns), with a high deposition (repairing) rate, and β‐FeOOH nanorods (Fe‐nr), with high oxygen evolution reaction (OER) ability, are electrostatically self‐assembled into composite catalysts. This strategy is developed to integrate multifunctionality in self‐repairing catalysts. Positively charged Co‐ns and negatively charged Fe‐nr form uniform composites when dispersed in an electrolyte. These composites are electrochemically deposited on a nickel electrode by electrolysis at 800 mA cm−2. Co‐ns form a conductive mesoporous assembly of CoOOH nanosheets as a support. Fe‐nr are then distributed on the CoOOH nanosheets as active sites for the OER. Because of the high deposition rate of Co‐ns, the amount of Fe‐nr deposited increases 22 times compared to when Fe‐nr is deposited alone, and the OER current density increases 14 times compared to that of Co‐ns alone. The composite self‐repair catalyst shows the highest activity and durability under an accelerated durability test (ADT), and its degradation rate decreases from 84 μV cycle−1 (Fe‐nr only) to 60 μV cycle−1 (composite catalyst) under ADT conditions without repair.

Aptamer regulated peroxidase-like activity of cobalt oxyhydroxide nanosheets for colorimetric detection of kanamycin.

A straightforward label-free colorimetric aptasensor utilizing the aptamer-enhanced peroxidase-like activity of cobalt oxyhydroxide (CoOOH) nanosheets has been established for kanamycin detection. In the kanamycin-free state, aptamers adsorb onto the CoOOH surface through electrostatic forces, enhancing the peroxidase-like activity of CoOOH and thereby resulting in a strong absorption signal and a yellow hue in 3,3',5,5'-tetramethylbenzidine (TMB) upon termination of the reaction with a stop solution. Conversely, upon the introduction of kanamycin, aptamers and CoOOH nanosheets compete for binding to kanamycin, resulting in a significant decrease in the number of aptamers bound to CoOOH. As a result, the activity of CoOOH diminishes, leading to a corresponding reduction in coloration and absorbance of the solution. Hence, the quantitative determination of kanamycin could be realized by analyzing the absorbance variations. Under optimal conditions, the aptasensor demonstrated high sensitivity and specificity, with a linear detection range from 500nM to 5µM and a detection limit as low as 54.6nM. Moreover, the aptasensor effectively identified kanamycin in river water samples, achieving a recovery rate between 91.7% and 102.1%. This approach offers good practicability and provides a novel platform for kanamycin detection in environmental samples.

Membrane separation assisted colorimetric/fluorescent detection of β-galactosidase-positive bacteria in milk and milk powder based on the oxidase-like activity of CoOOH nanosheets

Species-specific enzymes provide a substantial boost to the precision and selectivity of identifying dairy products contaminated with foodborne pathogens, due to their specificity for target organisms. In this study, we developed cobalt oxyhydroxide nanosheets (CoOOH NSs) for a dual-mode biosensor capable of detecting β-galactosidase (β-Gal)-positive bacteria in milk and milk powder. The sensor exploits the oxidase-mimicking activity of CoOOH NSs, where β-Gal converts the substrate β-D-galactopyranoside to p-aminophenol, reducing CoOOH NSs to Co2+ and inhibiting the formation of the blue product from 3,3′,5,5′-tetramethylben-zidine. Sensitivity was enhanced through membrane filtration and β-Gal induction by isopropyl β-D-thiogalactoside. The assay achieved a detection limit of 5 cfu mL−1 and demonstrated recoveries (90.7 % to 103 %) and relative standard deviations <5.7 % in milk and milk powder samples. These findings underscore the potential of the sensor for detecting β-Gal-positive bacteria in dairy products.

Detection of ascorbic acid by persistent luminescent nanoparticles based on CoOOH nanosheets modification.

Persistent luminescent nanomaterials (PLNPs) Zn0.8Ga2O4: Cr3+, Zr3+ with high brightness and good dispersion were prepared by hydrothermal method. The PLNPs were used as luminescent units, and CoOOH nanosheets were used as quenching agents. Based on the fluorescence internal filtering effect, the luminescence of PLNPs were effectively quenched by CoOOH modification on the surface of PLNPs. However, the introduction of ascorbic acid (AA) restored the luminescence of PLNPs and successfully achieved highly sensitive and selective detection of AA. This was due to a selective redox reaction between CoOOH and AA, in which CoOOH was reduced to Co2+. The degree of luminescence recovery of PLNPs showed a good linear relationship with AA concentration in the range 5-250 µM, with a detection limit of 0.72 µM. Therecovery of actualspikedsamples were 97.9-102.2%. This method isexpected to provide reference for the study of other redox substances in biological systems.

Foldable paper-based photoelectrochemical biosensor based on etching reaction of CoOOH nanosheets-coated laser-induced PbS/CdS/graphene for sensitive detection of ampicillin

Timely and rapid detection of antibiotic residues in the environment is conducive to safeguarding human health and promoting an ecological virtuous cycle. A foldable paper-based photoelectrochemical (PEC) sensor was successfully developed for the detection of ampicillin (AMP) based on glutathione/zirconium dioxide hollow nanorods/aptamer (GSH@ZrO2 HS@apt) modified cellulose paper as a reactive zone with laser direct-writing lead sulfide/cadmium sulfide/graphene (PbS/CdS/LIG) as photoelectrode and cobalt hydroxide (CoOOH) as a photoresist material. Initially, AMP was introduced into the paper-based reaction zone as a biogate aptamer, which specifically recognized the target and then left the ZrO2 HS surface, releasing glutathione (GSH) encapsulated inside. Subsequently, the introduction of GSH into the reaction region and etching of CoOOH nanosheets to expose the PbS/CdS/LIG photosensitive material increased photocurrent. Under optimal conditions, the paper-based PEC biosensor showed a linear response to AMP in the range of 5.0 - 2 × 104 pM with a detection limit of 1.36 pM (S/N = 3). In addition, the constructed PEC sensing platform has excellent selectivity, high stability and favorable reproducibility, and can be used to assess AMP residue levels in various real water samples (milk, tap water, river water), indicating its promising application in environmental antibiotic detection.

Edge interface microenvironment regulation of CoOOH/commercial activated carbon nano-hybrids enabling PMS activation for degrading ciprofloxacin

Peroxymonosulfate (PMS) is widely employed to generate oxygen-containing reactive species for ciprofloxacin (CIP) degradation. Herein, cobalt oxyhydroxide @activated carbon (CoOOH@AC) was synthesized via a wet chemical sedimentation method to activate PMS for degradation of CIP. The result suggested AC can support the vertical growth of CoOOH nanosheets to expose high-activity Co-contained edges, possessing efficient PMS activation and degradation activity and catalytic stability. In the presence of 3.0 mg of optimal CoOOH@AC and 2 mM PMS, 96.8 % of CIP was degraded within 10 min, approximately 11.6 and 9.97 times greater than those of CoOOH/PMS and AC/PMS systems. Notably, it was disclosed that the optimal CoOOH@AC/PMS system still exhibited efficient catalytic performance in a wide pH range, different organics and common co-existing ions. Quenching experiments and electron paramagnetic resonance indicated that both radical and non-radical processes contributed to the degradation of CIP, with 1O2 and direct electron transfer accounting for the non-radical pathway and SO4•− and •OH serving as the main radical active species. Finally, possible CIP degradation pathways were proposed based on high-performance liquid chromatography-mass spectrometry. This study provided an alternate method for wastewater treatment based on PMS catalyzed by cobalt-based hydroxide.

Electrochemically Induced Ru/CoOOH Synergistic Catalyst as Bifunctional Electrode Materials for Alkaline Overall Water Splitting.

Efficient and affordable price bifunctional electrocatalysts based on transition metal oxides for oxygen and hydrogen evolution reactions have a balanced efficiency, but it remains a significant challenge to control their activity and durability. Herein, a trace Ru (0.74 wt.%) decorated ultrathin CoOOH nanosheets (≈4 nm) supported on the surface of nickel foam (Ru/CoOOH@NF) is rationally designed via an electrochemically induced strategy to effectively drive the electrolysis of alkaline overall water splitting. The as-synthesized Ru/CoOOH@NF electrocatalysts integrate the advantages of a large number of different HER (Ru nanoclusters) and OER (CoOOH nanosheets) active sites as well as strong in-suit structure stability, thereby exhibiting exceptional catalytic activity. In particular, the ultra-low overpotential of the HER (36mV) and the OER (264mV) are implemented to achieve 10mAcm-2. Experimental and theoretical calculations also reveal that Ru/CoOOH@NF possesses high intrinsic conductivity, which facilitates electron release from H2O and H-OH bond breakage and accelerates electron/mass transfer by regulating the charge distribution. This work provides a new avenue for the rational design of low-cost and high-activity bifunctional electrocatalysts for large-scale water-splitting technology and expects to help contribute to the creation of various hybrid electrocatalysts.

Cobalt oxyhydroxide nanosheet-modulated ratiometric fluorescence platform for the selective detection of malachite green in fish.

A ratiometric fluorescence platform was developed based on the cobalt oxyhydroxide (CoOOH) nanosheet-modulated fluorescence response of blue emissive copper nanoclusters (Cu NCs) and yellow emissive o-phenylenediamine (OPD). CoOOH nanosheets showed dual function of strong absorption and oxidation ability, which can effectively quench the blue fluorescence of Cu NCs, with an excitation and emission peak maximum at 390 and 450nm, respectively, and transfer the OPD into yellow fluorescence products, with an excitation and emission peak maximum at 390 and 560nm, respectively. Upon introducing butyrylcholinesterase (BChE) and its substrates, CoOOH nanosheets were decomposed into Co2+, and malachite green (MG) showed strong inhibition ability to this process. This resulted in the obvious difference on the ratio of blue and yellow fluorescence recorded on the system in the presence and absence of MG, which was utilized for the quantitative detection of MG, with a limit of detection of 0.140μM and a coefficient of variation of 3.5%. Thefluorescence ratiometric assay showed excellent detection performances in practical sample analysis.

Mesoporous hydrogel electrodes with flexible frameworks exhibiting enhanced mass transport for the oxygen evolution reaction.

Mesoporous hydrogel electrodes with unique flexible mesopores surrounded by CoOOH nanosheets were prepared via the electrochemical deposition of hybrid cobalt hydroxide nanosheets, exhibiting high oxygen evolution reaction activity at a high current density owing to the enhanced mass transport of oxygen molecules.

“On–off–on” fluorescent sensor based on Ti3C2 quantum dots and CoOOH nanosheets for the detection of ascorbic acid

An “on–off–on” fluorescent sensor is constructed for AA detection by combining Ti3C2 QDs and CoOOH nanosheets.

Catalytic Active Sites Determination and Charge Transport of Transition Metal Oxides for Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is a key process that enables the storage of renewable energies in the form of chemical fuels.[1] Unraveling the catalytic mechanism is of paramount significance for the rational design of efficient electrocatalysts.[1] Here, we use well-defined crystalline cobalt oxyhydroxides CoOOH nanorods and nanosheets as model catalysts to investigate the geometric catalytic active sites.[2] We disclose a linear correlation of catalytic activities with their lateral surface areas, suggesting that the active sites are exclusively located at lateral facets rather than basal facets. Theoretical calculations show that the coordinatively unsaturated cobalt sites of lateral facets upshift the O 2p-band center closer to the Fermi level, thereby enhancing the covalency of Co-O bonds to yield the reactivity. Following this, we develop a eutectic dealloying strategy to activate the porous spinel NiFe2O4 nanowires with up to four metal cation substitutions.[3] Spinel oxide of NiFeXO4 (X= Fe, Ni, Al, Mo, Co, Cr, ~195 mV@10mA·cm-2) outperforms most spinel phase OER electrocatalysts and comparable to the state-of-the-art NiFe hydroxides. This work elucidates the geometrical catalytic active sites and enlightens the surface engineering for efficient OER catalysts. Besides, we studied the dependence of catalytic performances on electrical conductivities and unveils that charge transportability, to our surprise, regulates the reaction kinetics of the electronically accessible active sites.[4] Remarkably, the regulation extent correlates with the electrical conductivities, suggesting the strong coupling of the electrocatalytic process with electronic transport. Furthermore, we argue the origin of Ov-promoted catalytic activities of NiFe-based (oxy)hydroxides.[5] We uncover the pivotal role of charge transport for their electrocatalytic OER and propose that the superficial Ov imposes electron donation to the conductive band of NiFeOOH and therefore enables the regulation of electronic transport to switch on/off OER catalysis. The work highlights the pivotal role of electronic transportability in unfolding catalytic potential, holding both fundamental and technical implications for electrocatalysts. Fang Song, ..., and Xile Hu*. Am. Chem. Soc. 2018, 140, 7748; Fang Song, Xile Hu*. Nat. Commun. 2014, 5, 4477; Fang Song, Xile Hu*, J. Am. Chem. Soc. 2014, 136, 16481-16484; Fang Song, ..., Hao Ming Chen,* Clemence Corminboeuf,* Xile Hu *. ACS Cent. Sci. 2019, 5, 558; Chen, Wenshu; Gu, Jiajun*; Du, Yongping*; Song, Fang*; ...; Zhang, Di. Adv. Funct. Mater. 2019, 30, 2000551; Bowen Liu, ..., Fang Song,* Qinglei Liu.* ACS Nano 2022, 16, 9, 14121.Sihong Wang, Qu Jiang, ..., and Fang Song,* Commun. 2022, 13, 6650;Qiwen Zhang, ..., Fang Song*, Mingwei Chen, and Pan Liu*. ACS Nano 2023, 17, 1485.Haoyue Zhang,# Lingling Wu,# ..., and Fang Song*., ACS Appl. Mater. Interfaces, In revision.Haoyue Zhang,# Lingling Wu,# ..., and Fang Song*. ACS Catal. In press.

Facile and green sculptured engineering of 3D hierarchical porous metals via gaseous oxidation-reduction and their use in efficient oxygen evolution reactions

Hierarchical porous metals (HPMs) are advanced functional materials used in various applications. However, the current fabrication methods require extra sacrificial materials and generate chemical waste. Here, a facile gaseous oxidation-reduction (GOR) approach was developed to directly transform commercial metals into HPMs. Taking cobalt (Co) as a typical example, a series of hierarchical porous Co foils (HPCF) with controlled porous structures were successfully sculptured. Larger micron-sized pores were formed spontaneously by utilizing different oxidation rates between grain and grain boundaries for the oxidation, and nanoscale pores originated from volume contraction and spontaneous rearrangement of the metal atoms during reduction. This straightforward GOR approach avoids multiple processes and harsh chemical etching and generates water vapor as the only processing byproduct, making it a facile, green process, suitable for large-scale fabrication. When HPCF were used as self-supporting electrodes for the oxygen evolution reaction, DFT calculations and in situ spectroscopy indicated that abundant vacancy defects contained within the hierarchical pores enhanced *OH adsorption and promoted the reconstruction of highly active CoOOH nanosheets. As a result, the CoOOH/HPCF electrode demonstrated outstanding performance of 190 mV at 10 mA cm−2 and exceptional durability of 500 h at 100 mA cm−2, outperforming most reported nonprecious metal oxygen evolution reaction electrodes.

Multi-signal logic-gate sensing platform based on CoOOH nanoflakes for quantitative point-of-care detection of prostate specific antigen

Herein, we propose a cobalt oxyhydroxide (CoOOH) nanoflake-mediated multi-signal sensing system for the immediate detection of biomarkers. The platform employs monoclonal antibody Ab1-modified magnetic nanoparticles (CuFe2O4-Ab1) as the capture target and multiwalled carbon nanotubes (MWCNTs) modified with polyclonal antibody Ab2 and nicotinamide adenine dinucleotide (NADH) as the signal probe (Ab2-MWCNTs-APBA-NADH). By taking the prostate-specific antigen (PSA) as a target, the feasibility of the sensing platform was confirmed. When exposed to PSA, the sandwich immune complex (CuFe2O4-Ab1/PSA/Ab2-MWCNTs-APBA-NADH) was formed by antigen–antibody specific recognition. Thereafter, the NADH of the signal probe inhibited the peroxidase-like activity of the CoOOH nanosheets, leading to decreased pressure, weight and temperature responses in the sealed system, in line with the “INHIBIT” logic gate. The three responses had a strong linear relationship with PSA concentration, with relative standard deviations (RSD) of 0.1–1.5%. With simple procedures and straightforward readout strategies, the proposed method can be easily generalized for specific detection of other analytes by changing the antibodies.

Constructing flexible composite electrodes of low crystalline cobalt (Oxy)hydroxides nanosheet grown on carbon fiber cloth via self-reconstruction for electrochemical nitrate-to-ammonia conversion

Electrochemical conversion of NO3−-to NH3 via the nitrate reduction reaction (NO3−RR) is a promising approach for ammonia synthesis and “green hydrogen” storage. Constructing self-supporting and flexible composite electrodes is critical for portable devices of electrochemical conversion of NO3−-to NH3. In this study, carbon fiber cloth is used for a three-dimensional flexible electronic collector, and low-crystalline CoOOH nanosheets (LC-CoOOH NSs) grown on carbon fiber cloth were synthesized by potential induced self-reconstruction of cobalt Prussian blue analogues. The as-prepared self-supporting composite electrode exhibited improved NH3 yield rate. Further investigation revealed that the higher valence state of Co and the lower crystallinity are beneficial for NO3−-to-NH3 conversion. This work shows an example of efficient flexible composite electrode for NO3−-to-NH3 conversion.

Construction of a Label-Free Ratiometric Biosensor Based on Target Recycling Amplification and Hg-ZnSe QDs for Assay of BChE and OPs.

Herein, we constructed a label-free ratiometric fluorescence biosensing strategy for the determination of butyrylcholinesterase (BChE) activity and organophosphorus (OPs) concentration. BChE promoted the hydrolysis of iodized s-butyrylthiocholine (BTCh) into a reducing substance thiocholine, which can decompose CoOOH nanosheets (CoOOH NSs) to Co2+. Subsequently, the single-stranded DNA (ssDNA) on the surface of CoOOH NSs was released. Then, ssDNA hybridized with hairpin DNA (h-DNA) and triggered the target recycling amplification process, producing large amounts of G-quadruplex. After adding thioflavin T (ThT), the target BChE was converted into activatable G-quadruplex/ThT with an amplified yellow fluorescence signal. The addition of OPs could significantly inhibit the hydrolysis of BTCh by BChE and thus unable to produce the yellow fluorescence G-quadruplex/ThT complex. Throughout the entire process, the fluorescence intensity of Hg-ZnSe QDs as a reference signal remained unchanged at 630 nm. Furthermore, this work provided an effective approach for detecting the BChE activity in serum samples and OPs in fruits and vegetables.

The target-induced redox and diazotized reaction for colorimetric ratio detection of nitrite using CoOOH nanosheets as mimetic oxidase.

Nitrite is a commonly used food additive and water contaminant that has received widespread attention due to its harmful effects on humans. Here, a colorimetric ratio sensing platform for the detection of nitrite in foods as well as aquatic systems was developed via the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by CoOOH nanosheets (CoOOH NSs). Interestingly, in the presence of nitrite, TMB complexes in acidic environments can be oxidized and diazotized to produce yellow oxidized TMB (oxTMB) and diazotized TMB, resulting in the nitrite concentration-dependent ratio variation for the absorbance peaks at 655 and 450nm (A655/A450). The colorimetric ratio sensing offers higher sensitivity and better selectivity compared to conventional detection methods because of the specific target-induced reduction-oxidation and diazotized reaction, as well as the excellent mimetic oxidase activity of CoOOH NSs. Based on this strategy, a smartphone-assisted portable approach was designed for the in-situ/visual detection of nitrite, which has good application prospects.

A resonant energy transfer electrochemiluminescence immunosensor based on low trigger potential of Zn-metal organic framework and CoOOH nanosheets for 5-fluorouracil detection

The organic luminophores have inspired widespread interest in electrochemiluminescence (ECL). Herein, a novel rod-like metal-organic framework was formed by chelating Zn ion with 9,10-di(p-carboxyphenyl)-anthracene (DPA), defined as Zn-MOF for simplicity. In this proposal, the prepared Zn-MOF was first used as a powerful organic luminophore with low trigger potential, thus developing a competitive ECL immunoassay for ultrasensitive detection of 5-fluorouracil (5-FU) with 1,4-diazabicyclo[2.2.2]octane (D-H2) as the coreactant. The absorption spectrum of cobalt oxyhydroxide (CoOOH) nanosheets and the ECL emission spectrum of Zn-MOF could be highly matched, which ensured the occurrence of resonance energy transfer (RET). For that, ECL-RET was applied in the assembly strategy of the ECL biosensor, and Zn-MOF was used as the energy donor and CoOOH nanosheets as the acceptor. Taking advantage of the luminophore and ECL-RET, the immunoassay can be used for ultra-sensitive quantitative detection of 5-fluorouracil. The proposed ECL-RET immunosensor showed satisfactory sensitivity and accuracy with a wider linear range from 0.001 to 1000 ng/mL, and a lower detection limit (0.52 pg/mL). Hence, it is worth believing that this strategy can pave a bright research direction for the detection of 5-FU or other biological small molecules.

Immobilization CoOOH nanosheets on biochar for peroxymonosulfate activation: Built-in electric field mediated radical and non-radical pathways

The strong electron interaction between metal oxide–carbon-based catalyst components plays a vital role in the peroxymonosulfate (PMS) activation for pollutant degradation. Herein, a novel CoOOH nanosheets anchored on rape straw-derived biochar (BC) surface (labeled as CoOOH/BC) as an efficient PMS activator toward degrading sulfamethoxazole (SMX) was synthesized. Experimental results indicated that integrating CoOOH nanosheets on the BC surface could inhibit CoOOH aggregation to increase the specific surface areas, exert a component synergistic effect to enhance activation degradation activity, and improve the catalyst stability. As a result, a 96 % degradation efficiency of SMX was achieved within 20 min over 20 wt% CoOOH/BC composite catalyst under the optimal conditions. Density functional theory (DFT) calculations disclosed that a built-in electric field (BIEF) pointing from BC to CoOOH was constructed at their interface, which could mediate PMS activation for reactive oxygen species (ROS) generation and induce direct electron transfer from SMX to PMS, resulting in efficient SMX degradation via both radical and non-radical pathways. Moreover, quenching experiments and electron paramagnetic resonance (EPR) measurements confirmed that single oxide (1O2) and superoxide radical (O2·-) are the dominant active species in the current system. Additionally, the possible SMX degradation routes were reasonably proposed based on liquid chromatography-mass spectrometry (LC-MS) results. This work provides an in-depth understanding of the role of BIEF in PMS activation, and expands the application of biochar-based materials in the field of environmental remediation.

Detection and Bioimaging of Glutathione in Cells via a Turn-On Near-Infrared Fluorescent Nanoprobe Composed of Ag2S Quantum Dots and CoOOH Nanosheets

The variations of the microenvironment in cells are always associated with changes in the concentrations of some active species. However, visual detection of these species is still a challenge. In this work, near-infrared (NIR)-emitting fluorescent Ag2S quantum dots (Ag2S QDs) were synthesized via a rapid microwave reaction under normoxic conditions, which were utilized as sensitive fluorescent nanoprobes in sensing and bioimaging of glutathione (GSH) combined with CoOOH nanosheets (CoOOH NSs). The negatively charged Ag2S QDs can easily and effectively attach to the surface of CoOOH NSs to form the Ag2S QD/CoOOH nanoprobe through electrostatic interactions, accompanied by the quenching of the fluorescence of Ag2S QDs at 685 nm via the inner-filter effect (IFE). However, upon the addition of GSH, the fluorescence of Ag2S QDs was recovered due to the reduction of CoOOH NSs into Co2+ by GSH. Meanwhile, the fluorescent emission wavelength shifts slightly, which may result from the ligand exchange reaction between GSH and d-penicillamine (DPA) to form comodified Ag2S QDs. Based on the low toxicity and high tissue penetration depth of the NIR fluorescence of the Ag2S QDs and the good biocompatibility of CoOOH NSs, the nanoprobe composed of Ag2S QDs and CoOOH NSs was successfully applied in bioimaging, which can distinguish the normal cells and cancer cells, the semiquantitative content of endogenous and exogenous GSH. The as-developed strategy not only provides a simple, convenient, cost-effective, and rapid platform for the diagnosis of clinical diseases related to GSH but shows great prospects in fluorescence-assisted surgery.