Low-Frequency Evolution Mechanism of Customized HEAs-Based Electromagnetic Response Modes Manipulated by Carbothermal Shock.

An emerging carbothermal shock method is an ultra-convenient strategy for synthesizing high-entropy alloys (HEAs), in which the intelligent combination of carbon support and HEAs can be serve as a decisive factor for interpreting the trade-off relationship between conductive gene and dielectric gene. However, the feedback mechanism of HEAs ordering degree on electromagnetic (EM) response in 2-18 GHz has not been comprehensively demystified. Herein, while lignin-based carbon fiber paper (L-CFP) as carbon support, L-CFP/FeCoNiCuZn-X with is prepared by carbothermal shock method. The reflection loss of -82.6 dB with thickness of 1.31 mm is achieved by means of pointing electron enrichment within L-CFP/FeCoNiCuZn HEAs heterointerfaces verified by theoretical calculations. Simultaneously, low-frequency evolution with high-intensity and broadband EM response relies on a "sacrificing" strategy achieved by construction of polymorphic L-CFP/semi-disordered-HEAs heterointerfaces. The practicality of L-CFP/FeCoNiCuZn-X in complex environments is given prominence to thermal conductivity, hydrophobicity, and electrocatalytic property. This work is of great significance for insightful mechanism analysis of HEAs in the application of electromagnetic wave absorption.

Response surface optimization of ionic liquid pretreatments for maximizing cellulose nanofibril production.

Pretreatments with aqueous protic ionic liquid (PIL)-ethanolamine bis(oxalate) ([MEA][(HOA)(H2OA)]), combined with ultrasonic disintegration, were employed in cellulose nanofibril (CNF) production from pulp fibers. The optimization of pretreatment parameters is crucial for obtaining the maximum CNF yield. The response surface methodology was used to design the pretreatment conditions for preparing CNFs. This method consists of four factors: pretreatment time (A, 2-4 h), pretreatment temperature (B, 100-120 °C), liquid-to-solid ratio (C, 60-80 g g-1), and PIL content (D, 20-40%). The predicted CNF yield (Y) followed a quadratic multinomial regression equation represented by Y = 84.43 + 3.59A + 8.22B + 2.22C - 2.13D - 0.85AB + 2.83AC + 5.95AD + 0.43BC - 2.98BD + 4.25CD - 6.04A2 - 18.23B2 - 4.98C2 - 7.39D2. The regression equation exhibited high model fit to the experimental CNF yields as evidenced by a determination coefficient of 0.9764. Results showed that a maximum CNF yield of 86.2% was obtained in the case with the following conditions: pretreatment temperature of 112 °C, pretreatment time of 3.2 h, liquid-to-solid ratio of 83 g g-1, and PIL content of 29%. CNFs with high crystalline index (64.0%) and thermal stability (Tmax = 348 °C) were prepared. This work favors the development of low cost PIL-based pretreatment systems for the clean production of CNFs.

PDMS/magnetic lignin sponge for oil/water separation.

Recyclable, non-toxic, and degradable biological substrates contribute significantly to super-wetting surfaces. In this work, we prepared magnetic micro-nano super-hydrophobic surfaces through a robust solution with magnetic modified lignin particles as the supporting structure. A novel PDMS (polydimethylsiloxane)/magnetic lignin particle (lignin@Fe3O4)/PDA sponge composite was fabricated. Through dopamine (DA) self-polymerization, covalent deposition of magnetic lignin (ML), and PDMS silane modification, the magnetic super-hydrophobic polyurethane sponge composite (Sponge-P) was synthesized so that the Fe3O4 nanoscale microspheres wrapped with microscale lignin magnetic particles adhered to the sponge surface tighter and were barely dislodged. The as-prepared Sponge-P displayed excellent flexibility and a water contact angle of up to 152.2°. The super-hydrophobic sponge prepared with the proposed method was acid-base stable (pH = 2-12), self-cleaning, and suitable for high-salinity seawater. The magnetic super-hydrophobic sponge has good oil-water separation ability and can absorb 43 times its own weight of oil. In the meantime, due to the introduction of magnetic materials into lignin, we not only constructed micro-nanostructures to improve the surface super-hydrophobicity, but also made Sponge-P have the function of magnetic recovery, which has a unique advantage in treating oily wastewater.

Efficient hydrodeoxygenation of methyl levulinate into pentanoic biofuels over Ru/USY catalysts.

Catalytic hydrodeoxygenation of neat methyl levulinate into pentanoic biofuels is one of the pivotal reactions in biomass valorization. A combined pentanoic acid/methyl pentanoate yield of 92% can be achieved for Ru/USY with a Si/Al ratio of 15 at 220 °C and 40 bar H2. The superior performance of Ru/USY-15 for the efficient production of pentanoic biofuels is attributed to the optimal site balance between the Ru species and strong acid sites (ca. 1 : 5).

Designed formation of C/Fe3O4@Ni(OH)2 cathode with enhanced pseudocapacitance for asymmetric supercapacitors.

The rational design and synthesis of advanced electrode materials are significant for the applications of supercapacitors. Ferroferric oxide (Fe3O4), with its high theoretical capacitance is a renowned cathode material. Nevertheless, its low electronic conductivity and poor cycling stability during a long-term charge/discharge process limit its large-scale applications. In this work, the precise modulation of multiple components was reported to enhance electrochemical performance. The ternary heterostructures were fabricated by wrapping ultrathin nickel hydroxide (Ni(OH)2) nanosheets on the surfaces of Fe3O4 nanoparticles-loaded on sodium carboxymethyl cellulose (CMC)-derived porous carbon, named as C/Fe3O4@Ni(OH)2. Due to the large specific surface area and excellent conductivity of CMC-derived porous carbon and the abundant reaction sites of Ni(OH)2 nanosheets, the optimized C/Fe3O4@Ni(OH)2-1.0 sample exhibited the highest specific capacitance of 3072F g-1 at a current density of 0.5 A g-1. Furthermore, the assembled asymmetric supercapacitor (ASC) with activated carbon and C/Fe3O4@Ni(OH)2-1.0 as the negative and positive electrodes, respectively, showed an energy density of 123 W h kg-1 at 381 W kg-1, and a long-life stability with an excellent capacitance retention of 90.04 % after 10,000 cycles. The route for preparing composite electrode materials proposed in this work provides a reference for realizing high-performance energy storage devices.

Construction of CuO/Cu-nanoflowers loaded on chitosan-derived porous carbon for high energy density supercapacitors.

Copper oxide (CuO) and copper (Cu) have been viewed as the prospective pseudocapacitive electrode materials for supercapacitors. Nevertheless, the poor electron transfer capacity, loading amount, and cycling stability limit their wide applications, which can be addressed by developing the CuO based heterojunction on conductive carbons. Here, a CuO/Cu@C comprising CuO/Cu nanoflowers and chitosan-derived N-doped porous carbon was compounded by simple mechanical mixing, freeze-drying, and carbonization. The composite heated at 700 °C exhibited a high specific capacitance of 2479F/g at 0.5 A/g and excellent cycling stability with capacitance retention of 82.43 % after 10 000 charge-discharge cycles. In addition, the asymmetric supercapacitor (ASC), i.e., CuO/Cu@C-700//AC assembled by CuO/Cu@C (as a positive electrode) and activated carbon (AC, as a negative electrode) displayed a great energy density of 76.87 W h kg-1 at 374.5 W kg-1 and kept as high as 25.83 W h kg-1 even at 14998 W kg-1. Our work provides a new pathway to preparing transition metal oxide-based electrode materials with distinguished electrochemical performances.

Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction.

The development of g-C3N4-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C3N4 nanosheet-coated alginate-based hierarchical porous carbon (g-C3N4@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C3N4 nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C3N4@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH4 system, which included photocatalytic reduction of H+ ions and photocatalytic oxidation of BH4- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.

Controllable construction of multifunctional superhydrophobic coating with ultra-stable efficiency for oily water treatment.

Designing interfacial coating with tailored characteristics is a crucial step in regulating the wetting properties of oil/water separation materials; however, the controllable fabrication of multifunctional layer with long-term durability in harsh environments remains challenging. Fabrication of raised dots based on magnetic Fe3O4 particles on micro-nanometer units, inspired by mussel chemistry, under the adhesion behavior of dopamine (DA) self-polymerization covalent deposition of Fe3O4 particles and hydrophobic polydimethylsiloxane (PDMS) modification to synthesize magnetic superhydrophobic cotton composites (Cotton-P). Due to the unique magnetic and superhydrophobic surface composition, the synthetic Cotton-P possesses superhydrophobic (155.4°) and magnetic properties and still exhibits these excellent properties after 10 cycles. In addition, the hydrophobicity of magnetic monolithic cotton is virtually unaffected in harsh environments. The chemical/thermal stability of the Cotton-P composite is improved due to the rigid silane coating on the skeleton. Moreover, the Cotton-P revealed excellent oil/water separation efficiency of over 98 % after 10 cycles. Based on these outstanding properties, Cotton-P has the potential to develop in the treatment of oil-water mixtures.

Rationally designed carboxymethylcellulose-based sorbents crosslinked by targeted ions for static and dynamic capture of heavy metals: Easy recovery and affinity mechanism.

A separable spherical bio-adsorbent (CMC-Cr) was prepared for capturing heavy metal ions by simple coordination and cross-linking between targeted ions of Cr3+ and carboxymethyl cellulose (CMC). A simple alternation of the CMC incorporation allowed the interconnected networks within the microspheres of preformed solid CMC to be adjusted. The excellent network structure could achieve the maximum collision between the adsorbent and the heavy metal cations in the wastewater. Through investigations, CMC-Cr-2 beads were determined as the optimal adsorbent. The adsorption performance of novel materials was evaluated by examining their adsorption behavior on Pb(II) and Co(II) under both static and dynamic conditions. The results showed that the adsorption behavior of CMC-Cr-2 beads on both two heavy metal cations could be fully reflected by the Freundlich model. Under the theoretical conditions, the maximum adsorption capacities were 97.26 and 144.74 mg/g. The kinetic results for the adsorption of two heavy metal cations on CMC-Cr-2 beads were consistent with the Pseudo-second-order kinetic model. Moreover, the correlation coefficient of the Thomas model was significant in the dynamic adsorption performance tests. Five regeneration cycle studies were successfully carried out on CMC-Cr-2 beads to evaluate reusability and stability. The applicability of CMC-Cr-2 beads in authentic aqueous solutions (both the single and binary pollutant systems) was also studied, and the results indicated that CMC-Cr-2 beads had a high potential for practical implementation. Furthermore, by analyzing the surface interactions of two heavy metal cations with the CMC-Cr-2 beads based on FTIR and XPS characterization, a basic understanding of the interaction between bio-sorbents and pollutants in wastewater can be obtained.

Construction of nickel ferrite nanoparticle-loaded on carboxymethyl cellulose-derived porous carbon for efficient pseudocapacitive energy storage.

The preparation of biomass-derived carbon electrode materials with abundant active sites is suitable for development of energy-storage systems with high energy and power densities. Herein, a hybrid material consisting of highly-dispersed nickel ferrite nanoparticle on 3D hierarchical carboxymethyl cellulose-derived porous carbon (NiFe2O4/CPC) was prepared by simple annealing treatment. The synergistic effects of NiFe2O4 species with multiple oxidation states and 3D porous carbon with a large specific surface area offered abundant active centers, fast electron/ion transport, and robust structural stability, thereby showing the excellent performance of the electrochemical capacitor. The best performing sample (NiFe2O4/CPC-800) exhibited a superior capacitance of 2894F g-1 at a current density of 0.5 A g-1. Encouragingly, an asymmetric supercapacitor with NiFe2O4/CPC-800 as a positive electrode and activated carbon as a negative electrode delivered a high energy density of 135.2 W h kg-1 along with an improved power density of 10.04 kW kg-1. Meanwhile, the superior cycling stability of 90.2% over 10,000 cycles at 5 A g-1 was achieved. Overall, the presented work offers a guideline for the design and preparation of advanced electrode materials for energy-storage systems.

Enhanced oxidative depolymerization of lignin in cooperative imidazolium-based ionic liquid binary mixtures.

The aerobic oxidation of lignin model 2-phenoxyacetophenone (2-PAP) in cooperative ionic liquid mixtures (CoILs) with 1-ethyl-3-methylimidazolium acetate ([C2C1im]OAc) and 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BZC1im]NTf2) was investigated. Complete degradation of 2-PAP was achieved with [C2C1im]OAc/[BZC1im]NTf2 molar ratio (RIL) of 1/1 and 1/2 at 100 °C for 2 h. The conversion and product yields from CoILs were higher than those in pure ILs, indicating the cooperative effects of [C2C1im]OAc/[BZC1im]NTf2 on cleaving aryl-ether bonds. [C2C1im]OAc promoted the catalytic cleavage of aryl-ether bonds and solvation, and [BZC1im]NTf2 induced the formation of alkyl radicals and enhanced the product selectivity. Accordingly, the highest conversion of alkali lignin (79.8%) was obtained with RIL of 5/1 at 100 °C for 2 h, and phenol monomers (306 mg/g) were selectively produced. The CoILs exhibited good catalytic capacities for oxidative depolymerization of lignin, which strongly depends on the changes in intermolecular interactions and structural organization with varying RIL.

Bi-layered hollow amphoteric composites: Rational construction and ultra-efficient sorption performance for anionic Cr(VI) and cationic Cu(II) ions.

Here, we have developed a novel bilayer hollow amphiphilic biosorbent (BHAB-3) with large adsorption capacity, rapid adsorption kinetics, and cost-effective for the removal of Cr(VI) and Cu(II) from aqueous solutions. The synthesis was based on the clever use of freeze-drying to fix the structure, secondary modification of the carboxymethyl cellulose microspheres with polyethyleneimine and cross-linking by glutaraldehyde. The consequences of pH, initial concentration, contact time and temperature on adsorption were investigated. The Langmuir model fits showed that the maximum adsorption capacities of the two target heavy metal ions reached 835.91 and 294.79 mg/g, respectively. Moreover, BHAB-3 was characterized by SEM, FT-IR, TGA, and XPS synergistically, showing that it exhibits a strong complexation ability for Cu(II) and a strong electrostatic effect for Cr(VI). Adsorption and desorption experiments showed only a slight decrease in the adsorption capacity of the BHAB-3 for Cr(VI) and Cu(II) ions after 5 and 26 cycles, respectively. Given the excellent properties of this adsorbent, it is a promising candidate for heavy metal ion removal.

Biochar/Mg-Al spinel carboxymethyl cellulose-La hydrogels with cationic polymeric layers for selective phosphate capture.

Recently, biochar-related phosphate sorbents have been extensively investigated and achieved significant progress; however, there is still much room for enhancement on capturing performance and recovery of powdery ones after sorption. Herein, a new kind of adsorbent, in which biochar/Mg-Al spinel encapsulated in carboxymethyl cellulose-La hydrogels with cationic polymeric layers, was fabricated, aiming for integrating multi-advantages of each component for enhanced phosphate capture. Batch static experiments were correlated to the phosphate adsorption performance of the adsorbent. The maximum phosphate adsorption capacity of the adsorbent was 89.65 mg P/g at pH = 3. The Langmuir isotherm model and the pseudo-second-order kinetic model fitted well with the adsorption behavior of the adsorbent. More importantly, this composite adsorbent that integrated with biochar, Mg-Al spinel, cationic polymeric components exhibited favorable selectivity over coexisting anions (Cl-, SO42-, HCO3- and NO3-) and performed good reusability after five consecutive cycles. By virtue of the bead-like feature, fixed-bed column experiments demonstrated that the Thomas model fitted the breakthrough curves well under varied experimental conditions. The adsorption mechanism of phosphate on the designed composite adsorbent with multi-components could be described as the electrostatic attraction, ligand exchange and inner-sphere complexation, which might account for the efficient phosphate capturing performance.

Three-dimensional hierarchical porous lignin-derived carbon/WO3 for high-performance solid-state planar micro-supercapacitor.

The development of advanced energy storage systems, such as rechargeable batteries and supercapacitors (SCs), is one of the great challenges related to energy demand with the rapid development of world economy. Herein, a three-dimensional hierarchical porous lignin-derived carbon/WO3 (HPC/WO3) was prepared by carbonization and solvothermal process. This electrode material for supercapacitor can be operated at a wide voltage window range of -0.4 V to 1.0 V. More importantly, 3HPC/WO3 with ultrahigh mass loading (~3.56 mg cm-2) has excellent specific capacitance of 432 F g-1 at 0.5 A g-1 and cycling stability of 86.6% after 10,000 cycles at 10 A g-1. The as-assembled asymmetrical supercapacitor shows an energy density of 34.2 W h kg-1 at a power density of 237 W kg-1 and energy density of 16 W h kg-1 at a power density is 14,300 W kg-1. A solid-state planar micro-supercapacitor (MSC) was fabricated using HPC/WO3 nanocomposites. Moreover, the calculated specific capacity of MSC was 20 mF cm-2 in polyvinyl alcohol-sulfuric acid gel electrolyte. Overall, through the reasonable design of HPC/WO3 nanocomposite materials and the efficient assembly of MSCs, the performance of the device was greatly improved, thus providing a clear strategy for the development of energy storage devices.

Facile transformation of carboxymethyl cellulose beads into hollow composites for dye adsorption.

Novel millimeter hollow microspheres were fabricated from carboxymethyl cellulose microspheres and polyethyleneimine using glutaraldehyde as a crosslinking agent. The hollow microspheres prepared with different polyethyleneimine usages and different polyethyleneimine treatment time were investigated deeply and characterized via SEM-EDX, FT-IR, and BET surface area analysis. It was shown that polyethyleneimine could break the coordination bonds between the carboxyl and Al (III) in carboxymethyl cellulose microspheres, leading to the formation of hollow structures. Most importantly, the usage and treatment time of polyethyleneimine can distinctly tailor the structure of the carboxymethyl cellulose microspheres, resulting in the formation of different hollow microspheres with varied shell thickness and size. Most importantly, we found that the prepared hollow microspheres have excellent adsorption performance toward targeted methyl blue under testing conditions. By virtue of the large accessible amount of -NH2 groups and its unique hollow structure, this type of millimeter hollow microspheres have broad application prospects in the treatment of emerging contaminants in wastewater.

Magnetic aminated lignin/CeO2/Fe3O4 composites with tailored interfacial chemistry and affinity for selective phosphate removal.

Phosphorus (P) has brought a series of environmental problems while benefiting mankind. To reclaim phosphorus from wastewater efficiently and conveniently, a novel magnetic adsorbent with aminated lignin/CeO2/Fe3O4 composites (AL-NH2@Fe3O4-Ce) possessing a high affinity to phosphate and easily separated from aqueous solutions was developed in this work. The characterization results revealed that Fe and Ce elements have been doped into the aminated lignin successfully. Batch experiment results convinced that the maximum phosphate adsorption capacity of AL-NH2@Fe3O4-Ce was 183.72 mg P/g at pH = 3, which was roughly 4.5 times greater than aminated lignin and 8.5 times greater than cerium oxide, respectively. The adsorption isotherm was fitted well by the Langmuir model, and the adsorption kinetics was in line with the pseudo-second-order model. The adsorption thermodynamics indicated the adsorption process was spontaneous and naturally exothermic. Additionally, AL-NH2@Fe3O4-Ce exhibited high selectivity towards phosphate over common coexisting anions (Cl-, NO3-, HCO3-, SO42- and F-). After five consecutive cycles, the adsorption performance of AL-NH2@Fe3O4-Ce decreased by only 16% compared with the fresh adsorbent, indicating that AL-NH2@Fe3O4-Ce exhibited excellent recycling ability. The results of XPS analysis and batch experiments showed that the possible mechanisms were electrostatic attraction and inner-sphere complexation. The tailored interfacial chemistry affinity to phosphate as well as endowed magnetic property reveled AL-NH2@Fe3O4-Ce could be adopted as an up and coming adsorbent in phosphate removal process.

1-Ethyl-3-methylimidazolium acetate ionic liquid as simple and efficient catalytic system for the oxidative depolymerization of alkali lignin.

The oxidative depolymerization of alkali lignin (AL) in 1-ethyl-3-methylimidazolium acetate ([C2C1im]OAc) system without additional catalyst was investigated under mild conditions (initial O2 pressure of 1.5 MPa, 80 °C-100 °C). Compared with other ionic liquids (ILs), the cooperation of imidazolium cation and acetate anion successfully enhanced AL conversion. Among the investigated imidazolium acetate ILs with ethyl- to octyl-side chains, [C2C1im]OAc presented the best catalytic capacity for AL oxidative depolymerization. Adding an appropriate amount of water to [C2C1im]OAc can further improve the reaction efficiency. In the [C2C1im]OAc system with the addition of 0.10-0.25 mL of water, approximately 77 wt% AL was depolymerized into small molecule soluble products at 100 °C for 2 h. The extracted oil was composed mainly of phenolic derived compounds. With the use of the [C2C1im]OAc-based system, the specific inter-unit linkages of lignin were broken down, and residual lignin with low molecular weight and narrow polydispersity index (1.88-1.96) was obtained. Compared with that in AL conversion with fresh [C2C1im]OAc, only a minimal decrease (~3.2%) was observed with the recovered IL until the fifth cycle. These findings revealed that [C2C1im]OAc-based system is a simple and efficient catalytic system for lignin oxidative depolymerization.

Characterization of lignin streams during ionic liquid/hydrochloric acid/formaldehyde pretreatment of corn stalk.

This work investigated the role of formaldehyde (FA) in lignin anti-condensation during corn stalk pretreatment based on 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)/hydrochloric acid (HCl). As a result of the aldolization reactions between FA and lignin, the condensation of lignin fragments was inhibited, and lignin remained in soluble fragmental molecules. Characterizations on the compositional and structural changes of lignin and its degraded products during pretreatment (80 °C-100 °C, 2-5 h) with FA addition in comparison with those in DO/HCl/FA or [C4C1im]Cl/HCl were conducted. Results revealed that the structural features of lignin were affected by FA addition and solvent type. In the [C4C1im]Cl/HCl/FA system, FA stabilization was unfavorable for the cleavage of ß-O-4' bonds and lignin with low S/G ratio (3.4) and high molecular weight (Mw = 9920 g·mol-1) was extracted. The compositions of degraded products were considerably affected by FA addition.

Synergistic preparation of modified alginate aerogel with melamine/chitosan for efficiently selective adsorption of lead ions.

Superior mechanical properties, high adsorption capacity, and excellent regeneration property are crucial design criterions to develop a new-type aerogel for adsorptive applications towards heavy metal removal from water. Herein, chitosan and melamine not only introduced abundant functional groups to increase adsorbing sites for lead ions, but also reinforced the three-dimensional network skeleton structure of absorbents to improve the service life in adsorption applications. As-fabricated alginate/melamine/chitosan aerogel can extract Pb (II) from aqueous solution efficiently, i.e., the optimum adsorption quantity of 1331.6 mg/g at pH 5.5, which exhibited excellent and selective adsorption capacity for Pb (II) against the competition of coexisting divalent metal ions. More importantly, alginate/melamine/chitosan aerogel could be regenerated using dilute acidic solution and recovered well after eight adsorption-desorption cycles. This work might offer a new idea for design and preparation of biomass-based aerogel sorbents with promising prospect in the remediation of Pb (II)-contaminated wastewater.

Promotional effect of embedded Ni NPs in alginate-based carbon toward Pd NPs efficiency for high-concentration p-nitrophenol reduction.

Noble metal-based catalytic material with maximum utilization is of prime attraction for conserving rare metal resources. Herein, highly dispersion Ni nanoparticles (NPs)-modified N-doped mesoporous carbon material (Ni-N@C) was fabricated by pyrolysis of Ni2+/Histidine cross-linked alginate hydrogels. In a step forward, the obtained Ni-N@C nanocatalyst was treated by the solution of Pd2+, and tiny amount of Pd NPs were deposited on the surface of Ni via the reducibility of Ni to achieve the high dispersion of precious metals material. In the degradation of highly-concentration p-nitrophenol, the catalyst presents excellent performance which could completely degrade pollutants within a very short period. It was demonstrated that pre-embedded Ni NPs could not only increase the efficiency of Pd NPs but also endow the facile separation characteristic to the catalyst. Besides, the catalyst maintained favorable catalytic capacity even after five reaction cycles. In brief, this work may provide novel guidance for the maximum utilization of noble metal-modified mesoporous N-doped carbon-supported catalysts in practical applications of industrial and the treatment highly-concentration p-nitrophenol.