Surface Chemical Analysis Research Articles

Noninvasive biosensing 3D scaffold to monitor degradation: The potential of fluorescent PCL and PLGA for tissue engineering

AbstractThe nondestructive localization and traceability of polymers by fluorescent tagging has become a valuable tool for biomedical applications. Integration of fluorescent molecule to the pristine polymers could modify polymers' degradation rate which is still unpredictable from a scaffold application standpoint. The current study focused to understand the material perspective of fluorescently tagged biodegradable polymers such as polycaprolactone (PCL) and poly (d,l‐lactide‐co‐glycolide) (PLGA) with fluorescein amine isomer I (FITC). PCL‐FITC and PLGA‐FITC were characterized using FTIR for surface chemistry analysis and rheology for their mechanical properties. The grafted materials were utilized to form 3‐dimentional scaffolds, and their degradation was monitored under accelerated degradation conditions triggered by pH. It was found that PCL and PCL‐FITC had a very slow degradation rate, when compared to PLGA and PLGA‐FITC. Both the FITC tagged materials displayed a faster degradation rate compared to their respective pristine material. Biocompatibility of the FITC conjugated polymers was tested using human‐adipose derived stem cells (hADSCs) revealing that the sub products from the degradation of the polymers over 7 days did not negatively affect the cellular metabolic activity. This work highlights the significance of initial characterization of fluorescent modified polymers for future biomedical application.

Impact of high shear blending on distribution of magnesium stearate on lactose for dry powder inhaled formulations

The use of magnesium stearate along with lactose in Dry Powder Inhaler (DPI) formulations is increasing.The impact of different conditions of high shear blending on the distribution of magnesium stearate on lactose particles was investigated in this study. The formulated blends were manufactured using high shear blending of pre-blended coarse and fine lactose particles with 1.0% (w/w) magnesium stearate under different blending conditions, specifically blending speed and time. The effects of blending conditions on the distribution of magnesium stearate on lactose particles were clearly identifiable by characterizing the formulated blends by means of rheological evaluations, scanning electron microscopy, and chemical surface analysis using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Rheological properties were significantly affected in blends with magnesium stearate compared to blends without magnesium stearate. Blending speed exhibited a strong influence on the distribution of magnesium stearate on lactose surface, while blending time had relatively minor effect.

Evaluation of lactic and succinic acids as green depressants for selective flotation separation of bastnaesite from calcite

Bastnaesite is a primary natural source of light rare earth elements. Adequate flotation of bastnaesite, as a fluoro carbonate mineral, in the presence of various Ca-containing gangue minerals, such as calcite, is complex due to similar surface characteristics. This study aimed to develop an environmentally benign flotation reagent scheme using organic acids to enhance bastnaesite flotation while selectively depressing calcite. Systematic flotation, zeta potential, adsorption density, and X-ray photoelectron spectroscopy analyses were carried out using lactic acid (LA) and succinic acid (SA) as depressants and sodium oleate as a collector. The results of flotation and surface chemistry analyses demonstrated that organic acids preferentially adsorbed on the calcite surface, significantly reducing calcite recovery to below 20% and 10% when using lactic acid and succinic acid, respectively. The collective findings of this study demonstrate the tremendous potential of organic acids to be used as effective calcite depressants in bastnaesite flotation system.

Weighting the role of specific nitrogen and oxygen functionalities on porous carbons in formaldehyde removal: Combining surface chemistry analysis and factorial dimensionally reduction method

Two activated carbons (phosphoric acid activated, CG, and steam activated, SX) of marked differences in porosity and surface chemistry were modified by an introduction of oxygen, nitrogen or both heteroatoms and used as formaldehyde removal media at room temperature. Sorption of nitrogen, XPS, FTIR, thermal analysis and potentiometric titration were used to characterize the samples’ porosity and chemistry. Heating at 450, 600 and 950 °C affected the content and speciation of groups on the surface and led to complex porosity alterations. CG was more susceptible to changes in porosity and its surface accepted twice more nitrogen than that of SX. Pyridines and pyrroles were in majority, regardless the treatment. When in a high density in supermicropores and mesopores, they were found responsible for an increased surface activity for HCHO removal due to specific interactions. It increased up to an order of magnitude adding to the complex role of ultramicropores, and thus markedly enhanced the effective utilization of the carbon surface. CG, with more nitrogen overperformed the SX series. Even though pyridines and pyrroles were found active, the results suggested that quaternary nitrogen is an important specific center for HCHO adsorption and this finding was supported by a factorial dimensionally reduction method.

Coupling grid nanoindentation and surface chemical analysis to infer the mechanical properties of shale mineral phases

Shale is a low-permeability, multi-phase, and multi-scale composite material with intrinsic heterogeneity in micro-texture and mineralogical composition. In this paper, relationships between the microscale texture and constituent phases of shale were investigated using SEM (scanning electron microscopy)/BSE (backscatter electron imaging)-EDS (energy-dispersive x-ray spectroscopy) methods, together with grid nanoindentation experiments. The mechanical properties of the constituent phases of the carbonate-rich Longmaxi shale samples were extracted based on the spatial distribution of mineral phases and the indentation interaction volume. We analyze the effects of particle size on the interpreted mechanical properties and establish a characteristic length scale based on a probabilistic analysis. The identified characteristic length for extracting the mechanical properties of constituent mineral phases from the grid nanoindentation technique is about 5.8–11.7 μm, i.e., up to 10 times greater than that proposed in prior research. A multi-scale mechanical model was established with considerations of a self-consistent scheme for granular morphology to link the microscopic characteristics with the multi-scale mechanical properties of shales. The modeling results show that the stiffness and the strength of the homogenized nano-porous illite/quartz aggregates in Longmaxi shale can be assessed from the nano-scale mechanical properties of the mineral phases and the nano-scale porosity. This study paves the way to accessing the mechanical properties of the constituent phases of composite materials based on the properties of their building blocks and provides extensive insights into their complex mechanical behavior, representing a major step towards developing reliable multi-scale models for engineering applications.

Toward the future of firefighter gear: Assessing fluorinated and non-fluorinated outer shells following simulated on-the-job exposures.

In 2022, the occupation of firefighting was categorized as a "Group 1" carcinogen, meaning it is known to be carcinogenic to humans. The personal protective equipment that structural firefighters wear is designed to safeguard them from thermal, physical, and chemical hazards while maintaining thermo-physiological comfort. Typically, the outer layer of structural turnout gear is finished with a durable water and oil-repellent (DWR) based on per- and polyfluoroalkyl substances (PFAS) that helps limit exposure to water and hazardous liquids. The PFAS-based aqueous emulsion typically used in DWR finishes is highly persistent and can cause various health problems if absorbed into the body through ingestion, inhalation, and/or dermal absorption. In response, the U.S. Fire Service has begun using non-PFAS water repellants in firefighter turnout gear. This study aims to evaluate the performance of both traditional PFAS-based and alternative non-PFAS outer shell materials. The study involved exposing both PFAS-based and non-PFAS DWR outer shell materials in turnout composites to simulated job exposures (i.e., weathering, thermal exposure, and laundering) that artificially aged the materials. After exposures, samples were evaluated for repellency, durability, thermal protection, and surface chemistry analysis to determine any potential performance trade-offs that may exist. Non-PFAS outer shell fabrics were found not to be diesel/oil-repellent, posing a potential flammability hazard if exposed to diesel and subsequent flame on an emergency response. Both PFAS-based and non-PFAS sets of fabrics performed similarly in terms of thermal protective performance, tearing strength, and water repellency. The surface analysis suggests that both PFAS and non-PFAS chemistries can degrade and shed from fabrics during the aging process. The study indicates that firefighters should be educated and trained regarding the potential performance trade-offs, such as oil absorption and flammability concerns when transitioning to non-PFAS outer shell materials.

Surface chemistry analysis of acidified and nickel impregnated carbon for desulfurization of fuels

Emission norms tend to reduce sulfur content in transport fuels to 10ppm. Considering this new method like adsorptive desulfurization are widely researched. The main motive in adsorptive desulfurization is to selectively adsorb Dibenzothiophene (DBT) and 4,6-DimethylDBT. Considering this adsorbent with nickel impregnation and acidic surface functionalities were developed. Topographical and surface chemical features were studied of developed carbon adsorbents. Presence of carboxylic surface functionalities and reduced solid nickel was confirmed on adsorbents surfaces. In addition to this formation of nickel complexes due to neutralization of nickel ion and carboxylic groups was confirmed. This type of adsorbents can act as potential adsorbents for adsorption of DBT and 4,6-dimethyl DBT.

Tweaking the mechanical stability of Al1−xWxN ternary nitride alloys for hard coating applications, and study on their structural, photoluminescence and surface chemical analysis

This study focuses on the synthesis and achievement of ternary Al1−xWxN nitride films as hard coating materials. A dual-target DC reactive magnetron sputtering process was used to coat Al1−xWxN thin films on Si (100), glass, and transparent quartz substrates. The elemental analysis of the films was calculated by energy dispersion spectroscopy and the corresponding value of x changes from 0 to 1. The X-ray diffraction data showed a-axis orientation of the AlN films with hexagonal phase and amorphous nature for Al0.78W0.22N and Al0.58W0.42N films. Atomic force microscopy analysis showed that the surface morphology of Al0.78W0.22N films was better than that of AlN and Al0.3W0.7N films, as evidenced by the significantly lower root-mean-square roughness value of 1.79 nm compared to 5.78 and 13.9 nm, respectively. The resistivity of Al1−xWxN films was determined by a four-probe method and resulted in a record low value of 4.08 × 10−5 Ω-m for WN films. The photoluminescence emission spectra showed distinct peaks in the visible region at different wavelengths, and the deconvoluted blue emission peak was attributed to the native defects in the Al1−xWxN films. X-ray absorption spectroscopy data showed an increase in feature-a from Al0.78W0.22N to Al0.58W0.42N films, indicating stronger hybridization of N 2p with Al 3p and W 5d orbitals due to π * -resonance. The oxygen content calculated by X-ray photoelectron spectroscopy was 34.6, 35.39, and 19.74 at% on the surface of AlN, Al0.58W0.42N, and WN films, respectively. The surface oxidation of AlN films triggered the transfer of charge from nitrogen to oxygen on the surface of AlN films. The nanoindentation results showed that the Al0.3W0.7N films have hardness and elastic modulus of 17.84 GPa and 196.96 GPa, which are higher than those of the other Al1−xWxN films, while the AlN films have higher fracture toughness due to the reduction of contact pressure.

Work function measurement by ultraviolet photoelectron spectroscopy: Versailles project on advanced materials and standards interlaboratory study

We present the results of an interlaboratory study on work function (WF) measurements by ultraviolet photoelectron spectroscopy (UPS) conducted under the auspices of the Versailles Project on Advanced Materials and Standards. Two samples, gold (Au) film deposited on a flat Si(100) and highly oriented pyrolytic graphite (HOPG), were distributed to six different laboratories. Prior to UPS measurements, the samples underwent common sample pre-cleaning procedures: wet treatment and Ar+-sputtering in a vacuum for Au, and mechanical peeling in air for HOPG. Instrumental settings are adjusted for energy-scale calibration and sample bias optimization. The average reference WF value (WFref) and its expanded uncertainty (Uref) were calculated from each dataset that participants provided. The results of the Au sample demonstrated 5.40 ± 0.13 eV after Ar+ sputtering in vacuum, while the HOPG sample showed 4.62 ± 0.16 eV after mechanical peeling-off. Even though the participants used slightly different sample bias voltages and sample cleaning methods with various instruments, the results demonstrate remarkable consistency. Their consistency among the laboratories for both samples with high and low WF values provides a basis for establishing a new international standard for UPS in the surface chemical analysis community.

Plasma-grafting surface modifications to enhance membrane hydrophobicity for brine membrane distillation

In this study, a novel approach is presented to significantly enhance hydrophobicity and performance in direct contact membrane distillation (DCMD) against concentrated reverse osmosis (RO) brines by modifying commercially available polypropylene (PP), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) membranes using RF-plasma/absorption-grafting treatments with controlled fluorination. Grafting with 1H,1H,2H,2H-perfluorodecyl-triethoxysilane (PDTS) in an anhydrous medium was employed. Morphological, chemical, and electrokinetic surface analyses revealed increased hydrophobic properties, with fluoropolymers achieving the limit of superhydrophilicity and maintaining the original morphology. Modified membranes demonstrated stable percent salt rejection and moderately higher permeate flux yields than commercial counterparts, with improvements of 14 % for PP, 25 % for PVDF, and 9 % for PTFE. The two-step RF-Plasma-O2 treatment and silane absorption-grafting technique effectively enhance surface hydrophobicity and anti-wetting effect of these different inert polymeric membranes, improving their performance for membrane distillation (MD) in all cases. The findings of this study have significant implications for the development and optimization of membrane distillation and related technologies, especially in areas with limited access to high-quality energy and in industries that deal with highly concentrated feeds such as RO brines.

How the interplay between harvest time and climatic conditions drives the dynamics of hemp (Cannabis sativa L.) field retting

Dew retting, the selective biodegradation of industrial hemp (Cannabis sativa L.) stems after harvest, is a key field process for plant fiber use. The stage of maturity of the crop and the weather conditions during the subsequent dew retting process differ with hemp harvest time, which depends on the hemp valorization scenario. In this work, the aim was to investigate and rank the important factors that drive hemp retting, such as hemp harvest date, weather during retting, soil type under hemp mulch, and their interactions under agricultural field conditions. To this end, an experimental field trial was set up in the northeastern area of France (Champagne region), with two hemp harvest scenarios and two types of soil common to the agricultural area. Physicochemical hemp characteristics and climatic conditions were dynamically monitored during the retting periods. Dynamics of stem characteristics determined at the biomass level (dry matter loss) and the outer tissue level (surface analysis, chemical and thermal analysis) showed that the kinetics of retting followed similar patterns regardless of soil type for both harvest date scenarios. The kinetics were strongly and linearly related to air temperature, expressed as the number of normalized days at 15 °C, and to cumulative radiation during retting periods. The cumulative amounts of rain and dew explained the kinetics less than temperature and radiation, regardless of the retting scenario considered. The strong relationship observed between colorimetry and infrared spectroscopic data for characterizing the retting progress for both harvest scenarios paves the way for the development of tools to monitor changes in hemp stem quality.

Effect of metal ions on the flotation separation of biotite from quartz using mixed anionic/cationic collectors

Metal cations have great effects on the flotation of silicate minerals whereas the interaction mechanism is unclear. Single mineral flotation demonstrated that the recovery of biotite rose to 94.69% and 96.41%, and that of quartz declined to 1.21% and 2.01% after introducing small amounts of Ca2+ and Mg2+, respectively. Artificial mixed mineral tests indicated that Ca2+ and Mg2+ could increase the Gaudin's selectivity index by 11.98 and 11.37, respectively, compared with 11.53 without metal ions. QCM-D measurements revealed that sodium oleate (NaOL) and dodecylamine (DDA) could co-absorb on the biotite surface, and a rigid DDA layer formed on these surfaces with/without metal ions. Moreover, the adsorption of NaOL on the biotite surface could be enhanced by Mg2+, from dissipated to rigid adsorption, while that on the quartz surface was barely influenced. Surface chemistry analysis confirmed that metal ions acted as adsorption bridges between mineral surfaces and carboxylate, thereby enhancing the adsorption of collectors.

Bioinspired superhydrophobic SERS substrates for machine learning assisted miRNA detection in complex biomatrix below femtomolar limit

Surface-enhanced Raman spectroscopy (SERS) is an analytical method with high potential in the field of medicine. The design of SERS substrates, based on specific morphology and/or chemical modification, allow the recognition of the presence of specific analytes with precision close to a single-molecule detection limit. However, the SERS analysis of real samples is significantly complicated by the presence of a large number of “minor” molecules that can shield the signal from the target analyte and make it impossible to determine it in practice. In this work, an advanced SERS approach was used for the detection of cancer-related miRNA-21 in blood plasma, used as a molecular model background. The approach was based on the combination of the biomimetic plasmon-active SERS substrate, its tuned surface chemistry and advanced SERS data analysis, making use of artificial machine learning. In the first step, biomimetic SERS substrates were created using a butterfly wing as a starting template. The substrates were covered by thin Au layer and covalently grafted with hydrophobic chemical moieties to introduce superhydrophobic and water-adhesive properties. The self-concentration of the analyte on the substrates was achieved by minimizing the contact area between the analyte drop and the substrate, which is facilitated by surface superhydrophobicity and additionally enhanced by drop evaporation on the flipped over substrate. Due to the presence of cancer miRNA and blood plasma background, the measured SERS spectra represent a complex of interfering peaks. Thus, their interpretation was carried out using a specially trained machine learning model. As a result, reliable and repeatable quantitative detection of miRNAs below the femtomolar level (up to 10−16 M) on the background of human blood plasma becomes possible.

Band-gap engineering of zirconia by nitrogen doping in reactive HiPIMS: a step forward in developing innovative technologies for photocatalysts synthesis.

In the global context of climate change and carbon neutrality, this work proposes a strategy to improve the light absorption of photocatalytic water-splitting materials into the visible spectrum by anion doping. In this framework, reactive high power impulse magnetron sputtering (HiPIMS) of a pure Zr target in Ar/N2/O2 gas mixture was used for the deposition of crystalline zirconium oxynitride (ZrO2-xNx) thin films with variable nitrogen doping concentration and energy band-gap. The nitrogen content into these films was controlled by the discharge pulsing frequency, which controls the target surface poisoning and peak discharge current. The role of the nitrogen doping on the optical, structural, and photocatalytic properties of ZrO2-xNx films was investigated. UV-Vis-NIR spectroscopy was employed to investigate the optical properties and to assess the energy band-gap. Surface chemical analysis was performed using X-ray photoelectron spectroscopy, while structural analysis was carried out by X-ray diffraction. The increase in the pulse repetition frequency determined a build-up in the nitrogen content of the deposited ZrO2-xNx thin films from ∼10 to ∼25at.%. This leads to a narrowing of the optical band-gap energy from 3.43 to 2.20eV and endorses efficient absorption of visible light. Owing to its narrow bandgap, ZrO2-xNx thin films obtained by reactive HiPIMS can be used as visible light-driven photocatalyst. For the selected processing conditions (pulsing configuration and gas composition), it was found that reactive HiPIMS can suppress the hysteresis effect for a wide range of frequencies, leading to a stable deposition process with a smooth transition from compound to metal-sputtering mode.

The Tribological Mechanism of Chromium at Extreme Stress-temperature Conditions Simulating the Interior Ballistic Environment in Artillery Barrels

The tribological mechanism of bulk chromium materials has been investigated at high-temperature and high-stress conditions simulating the interior ballistic environment in gun barrels. The results show a higher level of weight change after testing at 1, 000 °C as compared to that at 600 °C. The topographical difference is more evident in the friction surface after testing at 1, 000 °C than that at 600 °C. The detailed analysis of surface morphology and chemistry indicates a tribological mechanism combining oxidative wear, abrasive wear, and adhesive wear at a testing temperature of 600 °C, whilst the tribological mechanism is combined with adhesive wear and oxidative wear at a testing temperature of 1, 000 °C.

Piezoelectric-catalytic degradation of organic dyes and catalytic reduction of Cr(VI) with BaCO3@BaTiO3 microspheres

Piezoelectric-catalytic degradation of organic and inorganic pollutants is an important feasible and green treatment method. In this study, novel BaCO3@BaTiO3 microspheres have been fabricated firstly by the hydrothermal-calcination method, and a variety of physical and chemical characterization and surface analysis methods, such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and Brunauer-Emmett-Teller (BET) analyses have been carried out. The piezoelectric-catalytic activity of the as-prepared composites has been also evaluated through the degradation of organic pollutants (Rhodamine B and Methylene blue) and catalytic reduction of heavy metal ions (Cr(VI)) with the help of ultrasound. The catalytic mechanism shows that the active substances for the catalytic degradation of dyes are hydroxyl radicals (•OH) and superoxide radicals (•O2−), and the active species that catalytically reduces Cr(VI) to Cr(III) is mainly the electrons (e−) produced by the separation of electron-hole pairs induced by mechanical force. The as-prepared microspheres catalyst has high piezoelectric-catalytic degradation ability and good catalytic cycle stability, which is a kind of green wastewater treatment catalyst with practical application prospect.

The Effect of Steel Electropolishing on the Tribological Behavior of a Steel–Bronze Pair in the Mixed and Boundary Lubrication Regimes

Electropolishing at high current densities without agitation of the electrolyte results in a pitting phenomenon that produces dimple-like surface features. Although pitting is unfavorable in the electropolishing process, its effect on surface modification, such as surface texturing, has not been thoroughly investigated. Surface topography and chemical composition analyses of electropolished steel revealed surface pits and an oxide surface layer, indicating the presence of surface texture and coating. The resulting surface is characterized by negative skewness and high kurtosis values. The tribological behavior of the electropolished steel-bronze pair is investigated by evaluating coefficients of friction and bronze wear using sliding tests conducted in mixed and boundary lubrication regimes. The results are compared to those of the ground steel-bronze pair. In the mixed and upper range of the boundary lubrication regime, coefficients of friction reduction up to 30% and shorter running-in phases are observed for electropolished steel (electropolished steel μavg = 0.019 vs. ground steel μavg = 0.028). In contrast, the coefficient of friction increased in the lower range of boundary lubrication regime by 50% (electropolished steel μavg = 0.098 vs. ground steel μavg = 0.065). Electropolishing, as a cost- and time-effective method applicable to complex geometries, presents an alternative method for achieving surface modifications aimed at friction reduction and improved tribological behavior for non-conformal contacts in the boundary and mixed lubrication regimes.

Efficient removal of pharmaceutical contaminants from water and wastewater using immobilized laccase on activated carbon derived from pomegranate peels

In this study, pomegranate peels (PPs) as an abundant fruit processing waste was used to produce cost-effective, eco-friendly, and high-quality activated carbon. The produced carbon (fossil free activated carbon) was used for immobilizing laccase to remove a range of emerging pollutants namely diclofenac, amoxicillin, carbamazepine, and ciprofloxacin from water and wastewater. The loaded activated carbon by laccase (LMPPs) and the unloaded one (MPPs) were characterized using advanced surface chemistry analysis techniques. MPPs was found to have a porous structure with a large surface area and an abundance of acidic functional groups. Laccase immobilization reduced surface area but added active degradation sites. The optimal immobilization parameters were determined as pH 4, 35 °C, and a laccase concentration of 2.5 mg/mL resulting in a 69.8% immobilization yield. The adsorption of the emerging pollutant onto MPPs is best characterized as a spontaneous endothermic process that adheres to the Langmuir isotherm and first-order kinetics. Using synergistic adsorption and enzymatic degradation, the target pollutants (50 mg/L) were eliminated in 2 h. In both water types, LMPPs outperformed MPPs. This study shows that pomegranate peels can effectively be harnessed as an enzyme carrier and adsorbent for the removal of emerging pollutants even from a complex sample matrix. The removal of contaminants from wastewater lasted five cycles, whereas it continued up to six cycles for water.

A carbon fiber paper based electrode of high activity for electro-oxidation of aqueous sulfur dioxide

Significant improvements in the activity of a carbon-based electrode for the electro-oxidation of aqueous sulfur dioxide were obtained by introducing surface oxygen functionalities through the anodization of carbon fiber paper (CFP) in sulfuric acid solution. Electrodes of varying surface oxygen content (2.9 atomic% to 25.6 atomic%) and relative proportion of different types of oxygen functional groups were obtained by changing the anodization potential and the concentration of sulfuric acid. The activity of the optimal electrode was quantified by exchange current density and charge transfer resistance, respectively. The exchange current density was about 2.17-times the pristine CFP electrode (17.6 × 10−4μA cm−2 compared to 8.09 × 10−4μA cm−2). The morphological and structural changes in the electrode on anodization were determined using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman analysis. The chemical analysis of the electrode surface, done using X-ray photoelectron spectroscopy (XPS), showed a strong correlation between the electrode’s activity and the ratio of the percentage of hydroxyl groups to the sum of percentages of epoxy and carbonyl groups. The electrode performed well in an accelerated stability test based on cyclic voltammetry for over 1000 cycles.

Insight into novel Fe3C/Mo2C@carbonized polyaniline activated PMS for parachlorophenol degradation: Key roles of Mo2+, C=O bonds and N-doping

Developing efficient heterogeneous catalysts are of great importance for utilizing peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) toward environment remediation. In this work, a novel composites Fe3C/Mo2C@CPANI are synthesized via hydrothermal and calcination with a precursor of metal salt and PANI. The derived Fe3C and Mo2C nanoparticles are wrapped into the nitrogen-doped carbon layer thanks to the rationally structure design, which can not only suppress metal ions leaching but also promote carbocatalysis by synergistic effect. The as-synthesized catalyst exhibited excellent performance in activating PMS with a fast 4-CP degradation rate (k = 0.79 min−1). On the basis of surface chemistry analysis, the graphite N, C=O group, Fe2+ and Mo2+ are considered to be active sites that responsible for PMS activation. The electron paramagnetic resonance (EPR) and competitive quenching test both witnessed the existence of SO4•−, •OH, O2•− and 1O2 in the Fe3C/Mo2C@CPANI-0.1/PMS system, while SO4•− and 1O2 are considered as dominant reactive oxygen species (ROSs). Additionally, the influences of various reaction parameters on 4-CP removal were systematically investigated, where Fe3C/Mo2C@CPANI-0.1 could maintain its catalytic capacity under different conditions. This study proposes a facile method for fabricating metal carbide/carbon hybrids with rational structure and brings new insights into the radical/nonradical pathway in PMS activation process.