Nitrobenzene Molecules Research Articles

Influence of support polarity on the selective hydrogenation of nitrostyrene over Pt-based heterogenous catalysts

Enhancing the selectivity of noble metal containing heterogeneous catalysts in the nitro group hydrogenation of functionalized nitroarenes is challenging due to high dependence of selectivity on the catalyst structure. Most reports focus on the influence of metal nanoparticles (NPs) size, confinement, and support-metal interactions, while the effect of support polarity remains unclear. Herein we investigate, for the first time, the influence of support polarity on the selective hydrogenation of NO2 in 3-nitrostyrene over Pt-based heterogeneous catalysts and compare it to the effects of Pt NPs size and location. To achieve this, we confined Pt NPs in the channels of the nonpolar Silicalite-1 (S-1) and benchmarked against catalysts with NPs of various sizes supported on polar SiO2 and nonpolar S-1.We demonstrate that support polarity is the key factor determining selectivity, surpassing the roles of Pt particle size and confinement. Catalysts with the nonpolar Silicalite-1 support exhibit higher NO2 selectivity compared to SiO2-based ones, with a threefold increase observed for Pt@S–S-1 compared to a commercial Pt/SiO2. DRIFT spectroscopy-monitored adsorption experiments and hydrogenation experiments of nitrobenzene and styrene model molecules show that the S-1 support favors the adsorption of –NO2 and the –NH2 formed during the reaction, impeding C=C hydrogenation. To a lower extent, the size of Pt NPs contributed to the obtained results with decreased C=C hydrogenation observed over smaller Pt NPs. Finally, confining Pt in the zeolite restricts the NPs growth during catalyst activation, resulting in a further decrease of particles size and C=C hydrogenation activity.

The First-Principles investigation of sensing and removal applications of nitrobenzene using pristine and Sc decorated B9N9 nanoring

Nitrobenzene (NB), an aromatic organic compound widely used in various industries, has several environmental risks. Due to its risks, reliable sensing mechanisms are crucial. In the present work, we investigated the potential of the pristine and Sc decorated B9N9 nanoring as a sensor for detection of the toxic NB molecule using density functional theory (DFT). We have analyzed the structural parameters, adsorption energy (Ead), highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), HOMO-LUMO gap, density of states (DOS) spectra, Mulliken charge transfer, dipole moment, IR spectra, non-covalent interactions (NCI) iso-surfaces, recovery time (τ) and work function (φ) before and after the adsorption of NB onto pristine and Sc decorated B9N9 nanorings. Our analysis revealed that the NB interacted optimally with the pristine B9N9 nanoring, as evidenced by changes in electronic properties and Ead value of −0.58 eV. However, the Sc decorated B9N9 nanoring indicated a strong interaction with NB with Ead of −4.09 eV at a proximal distance of 2.12 Å. Furthermore, our study demonstrated that the pristine B9N9 nanoring could be used as both an “electronic sensor” and “φ-type sensor”. Additionally, to esteem rapid recovery for practical feasibility, we calculated τ for both the pristine and Sc decorated B9N9 nanoring. The short τ of the pristine nanoring indicates its suitability as NB sensor. In contrast, the longer τ of the Sc decorated nanoring suggests its applicability for NB storage or its removal from the surroundings. Overall, our findings underscore the potential of pristine B9N9 nanoring as effective NB sensor and removal. We hope that our study will assist experimentalists to develope a reliable B9N9 nanoring based sensor for the detection of NB molecules.

Highly sensitive fluorescent nitrobenzene gas sensing by nitrogen-doped graphene quantum dots embedded in ZIF-8 nanocomposite

This study introduces a straightforward and highly sensitive luminescence gas sensor designed for the detection of nitrobenzene in gaseous state. The sensor utilizes an innovative composite composed of nitrogen doped graphene quantum dots (nGQDs) as luminescent materials, successfully encapsulated within the stable porous carrier zeolitic imidazolate framework-8 (ZIF-8). The resulting nGQD@ZIF-8 nanocomposite showed highly sensitive luminescence sensing towards nitrobenzene gas, with a wide linear detection range from 8 to 320 ppm, and the detection limits of sensor as low as 0.44 ppm. Moreover, the nGQD@ZIF-8 sensor demonstrated enhanced ppm-level sensitivity and long-term stability for nitrobenzene detection at room temperature, while maintaining high stability under varying humidity levels and exposure to high temperatures. This enhancement is attributed to the increased contact area provided by ZIF-8 matrix, facilitating adsorption of nitrobenzene molecules on nGQDs. The nGQD@ZIF-8 exhibited good selectivity towards nitrobenzene gas (57 %) compared to other nitro volatile organic compound (VOC) vapors (nitromethane and nitropropane), and almost no significant responses were observed for the other tested VOC vapors (methanol, acetone, formaldehyde, benzene). This can be attributed to the strong interaction between the electron-deficient nitrobenzene and the nGQD@ZIF-8 nanocomposite. Overall, the proposed gas sensor in this study showed high potential for a simple, efficient, and reliable detection of nitrobenzene gas in environmental monitoring.

Insights into nitrobenzene adsorption mechanism on apricot stone activated carbon: A study via statistical physics models and thermodynamic analysis

Statistical physics modelling was performed to analyze the adsorption forces and the thermodynamics of the removal of nitrobenzene molecules using an activated carbon obtained from apricot stones. This adsorbent was prepared using phosphoric acid activation and exhibited a surface area of 1762 m2 g−1, total pore volume of 1.09 cm3 g−1 and an experimental maximum adsorption capacity of 295.63 mg g−1 for nitrobenzene at 298 K. The removal of this organic molecule was exothermic. A double layer adsorption model with two energies was utilized to calculate the main steric parameters for the removal of this compound. This model was employed to perform a thermodynamic analysis of this adsorption system. It was concluded that 2 and 3 adsorption sites can be involved for the removal of nitrobenzene molecules on activated carbon surface. Physical interaction forces were expected to participate in the removal of this pollutant. This activated carbon can be regenerated with NaOH thus offering the alternative of its recycling to reduce the removal costs of this organic molecule from water.

Effect of biaxial strain and vacancy defects in 2D MoS2 monolayer for the sensing of nitrobenzene: A DFT investigation

Considering the increased release of toxic nitrobenzene (NB) molecules into the atmosphere, proposing a sensor material that could effectively remove it from the environment is essential. In this regard, we have investigated the NB adsorption performance of vacancy-defected (S, Mo and di S) and biaxially strained (−4 % to 4 %) MoS2 monolayers through density functional theory (DFT) simulations. Applying biaxial (tensile and compression) strain to the monolayer significantly increased the adsorption energy and charge transfer to −1.02 eV and 0.09 e, respectively, much greater than in the pristine case. The formation energy calculations verified the stability of (S, Mo, 2S) vacancy-defected MoS2 monolayer. The low formation energy of 3.3 eV suggests the ease of formation of MoS2 monolayer with single S vacancy. Introducing defects and strain improved the conductivity of the monolayer, thereby increasing the NB adsorption ability. The reasonable NB adsorption energy on the modified monolayer was due to the accelerated charge transfer and orbital interaction between the valence S 3p orbitals of MoS2 and 2p orbitals of O in NB. The recovery time of the strained and defective monolayers is the order of only a few seconds at 400 K, which is quite attainable. Therefore, this work put forth a more effective to improve the NB performance of the monolayer and can be a motivation for the further development of high-performance biomolecule sensors.

Enhanced nitrobenzene sensing in metal anchored gamma-graphyne: predictions from density functional theory

Nitrobenzene (NB), being a toxic industrial effluent, its adsorption performance on pristine and metals (Al, Cu and Sc) anchored 2D graphyne (GY) monolayer was studied systematically via the first principles DFT simulations. The NB was found to be weakly adsorbed on the pristine monolayer with an energy of −0.46 eV due to the long-range van der Waals interactions. The NB was strongly adsorbed on the anchored metal site except for the case of Cu. The adsorption energy calculations suggest that the Al-anchored GY monolayer is excellent for the NB sensing because of the reasonable adsorption energy of −1.18 eV, charge transfer of 0.57 e and attainable recovery time of 2.4 s at 450 K. The work function sensitivity of the Al anchored system towards the NB molecule is 10% higher than the pristine system. Moreover, the ab-initio molecular dynamics simulations have predicted the room temperature structural steadiness of the Al-anchored GY monolayer. Overall, our research suggests that the Al-anchored GY monolayer is promising to adsorb the NB molecules effectively and can be potentially applied as an excellent NB biomolecule sensor.

Defect engineering mediated molecules coordination activation for one-pot synthesis of secondary amine over Bi2MoO6 hierarchical microspheres

Bi2MoO6 hierarchical microspheres (BMO-SP) consisting of monolayer nanosheets with abundant surface oxygen defects and unsaturated Mo sites are constructed for the one-pot synthesis of secondary amine via a photocatalytic coupling reaction of nitrobenzene (NB) and benzyl alcohol (BA). The performance of this photocatalyst is 12 times higher than that of bulk Bi2MoO6 (BMO-bulk). Experiment results and density functional theory calculations reveal that surface oxygen defects induce more unsaturated Mo atoms facilitating the coordination activation of NB and BA molecules through the formation of –N–O···Mo and –C–O···Mo coordination, respectively. The surface oxygen defects also promote the separation of photogenerated carriers. More photogenerated holes transfer to the surface for oxidizing the activated BA while the photogenerated electrons are trapped by oxygen defects for reducing NB. Thus, the photocatalytic performance is markedly improved. This work successfully designs an efficient photocatalyst for the tandem reaction via surface defect engineering.

Water-induced synthesis of Pd nanotetrahedrons on g-C3N4 for highly efficient hydrogenation of nitroaromatic

g-C3N4 supported Pd nanotetrahedrons (Pd NTs@g-C3N4) are first prepared by an in-situ growth method with water-induced process. The unique Pd nanotetrahedrons with four (111) facets exposed have been prepared by simply varying the dosage of water without the other synthesis condition changed. The optimized Pd NTs@g-C3N4 exhibits higher activity (TOF value: 51462 h−1) toward the hydrogenation of nitrobenzene with respect to the commercial Pd/C. The enhanced activity is attributed to the small size and tetrahedral shape with higher surface energy and more active surface. Most importantly, the Pd NTs@g-C3N4 still shows excellent activity and selectivity for nitrobenzene hydrogenation without obviously deactivation after ten cycles. In addition, the vertical and parallel adsorption behaviors of nitrobenzene molecules on Pd (111) surface are analyzed in detail using the density functional theory (DFT) method, and the interaction mechanism between nitrobenzene and palladium is studied by the charge density difference method.

Synthesis, crystal structure, and sensing properties of organic molecules based on a Terbium-nitronyl nitroxide complex

A new Terbium-nitronyl nitroxide radical complex [Tb(hfac)3(NITPh-m-CHO)2]·0.5C7H16 (Tb-rad) (hfac = hexafluoroacetylacetonate; NITPh-m-CHO = 2-(3′-formylphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide) was prepared and characterized. Tb-rad crystallizes in triclinic space group P1¯, possessing a mononuclear structure, in which the geometrical configuration of Tb(III) is triangular dodecahedron consisted of six oxygen atoms from three hfac ligands and two oxygen atoms from the NO groups of two NITPh-m-CHO ligands. In Tb-rad, isolated mononuclear structures were connected to form 1D supramolecular chain structures via intermolecular π···π interaction and free n-heptane molecules fill the void in the crystal. Significantly, the luminescence explorations demonstrate that Tb-rad is an excellent fluorescent sensor for identifying nitrobenzene (NB) and nitromethane (NM) molecules. Because of the linear relationship at low concentration with the quenching constant (Ksv) is 5.4 × 105 and 6.6 × 103 M−1 for NB and NM, respectively, it can be considered as a potential luminescent sensor for detecting NB and NM molecules. Moreover, the possible sensing mechanisms of selective detection have been discussed in detail.

Simple and straightforward method to prepare highly dispersed Ni sites for selective nitrobenzene coupling to Azo/Azoxy compounds

Azo and azoxy compounds are essential substances for the chemical industry. The development of catalysts to produce these molecules directly from nitroarenes is highly desirable. Nevertheless, this reaction is extremely challenging since the catalyst should not only activate nitro-compounds but also avoids the complete reduction to amines. Beyond noble-metals, such as Au, nickel-containing catalysts have shown attention for nitroarenes coupling to produce azo/azoxy compounds. Recently, outstanding results were reported for the nitrobenzene coupling using Ni-N4 sites obtained via pyrolysis of Ni(phen). However, pyrolysis methods lack on the control of metal loading and morphology of the metal sites, clearly, a mix of nickel nanoparticles and atomic dispersed metal sites were obtained. Here, we present a simple and straightforward method to synthesize highly dispersed nickel sites stabilized on highly crystalline carbon nitrides with poly(heptazine imide) structure (PHI). This method allows fine control of the metal loading and leads to mostly highly dispersed nickel sites, enabling to investigate in depth the coordination sphere of the Ni-sites during the reaction. The synthesized catalysts (Ni-PHI) were applied to nitrobenzene coupling reactions, showing high yields towards azo/azoxybenzene (98 %) and the highest TOF (435 h−1) for this reaction in the literature under mild conditions. Raman spectroscopy analyses show that nickel sites are crucial to adsorb nitrobenzene molecules through N atoms, favoring the production of nitrosobenzene. Furthermore, Ni-PHI exhibit high stability under different cycles and can yield azo/azoxy molecules with a broad scope, revealing the wide versatility of this catalyst.

Pristine and metal decorated biphenylene monolayer for enhanced adsorption of nitrobenzene: A DFT approach

This work reports a first-principles density functional theory (DFT) investigation of nitrobenzene (NB) sensing in pristine and metal-decorated biphenylene (p-BP and m-BP, m = Sc, Cu, Li, and Pd) 2D monolayer. Though the proposed p-BP monolayer displayed excellent adsorption of NB molecule compared to other reported 2D materials, it gets physisorbed on the p-BP surface with −0.621 eV adsorption energy. The metal decoration drastically reformed the NB adsorption capacity of BP and induced remarkable changes to the electronic properties. The ab-initio molecular dynamics simulations were employed to analyze the room temperature structural integrity of the m-BP-based NB sensor. Among all the systems considered, the Pd decorated BP monolayer came out as the potential NB sensor with a reasonable adsorption energy of −1.42 eV, charge transfer of 0.38 e, the recovery time of 0.92 s at 598 K, and structural solidity at ambient temperature. The higher diffusion barrier of 0.99 eV confirmed that the Pd dopant does not show the tendency to form clusters. The study demonstrates that the Pd decorated BP is highly apposite for NB sensing and is beneficial for practical application. Our study opens a new avenue for designing and developing efficient biomolecule sensors.

Nitrobenzene detection using pristine and transition metal-decorated C[18] cyclocarbon: A first-principles density functional theory study

Carbon-based nanomaterials have been extensively used for gas or biomolecule sensing applications in recent years. Nitrobenzene (NB) is one of the major environmental pollutants, and its excessive discharge into the atmosphere is a serious menace to all living beings. Hence, effective sensing of the NB is required. In the present work, we have studied the NB adsorption properties of the recently discovered allotrope of carbon, cyclocarbon (C[18]), and transition metal (TM = Sc, Ti, and Cr)-decorated C[18] using the density functional theory method. The NB molecule is physisorbed on the pristine C[18] with a low adsorption energy of −0.49 eV. Among the three TMs, the Sc and Ti atoms strongly bind on the cyclocarbon with a binding energy of −2.47 and −1.87 eV, respectively, resulting in an improvement in the conductivity of the pristine C[18]. NB adsorption on the Sc-decorated system is found more favorable, with a considerably larger adsorption energy of −2.993 eV than the pristine C[18]. The improved adsorption is due to the orbital interaction and the charge transfer of 0.562e from the Sc 3d orbitals to the O 2p orbitals of the NO2 group in NB. This work could provide a theoretical foundation for developing a potentially novel NB sensor based on the TM-decorated C[18] cyclocarbon.

Photo enhanced catalytic activity for hydrogenation of nitrobenzene over Pt-Au/TiO2 heterojunction

Hydrogenation of nitroaromatics to the corresponding amines plays a central role in the drug, fine chemical, and petrochemical industry. However, realizing hydrogenation through highly effective and environment-friendly methods remains a significant challenge. Here we demonstrated photo-enhanced catalytic activity for hydrogenation of nitrobenzene using Pt-Au/TiO2 heterojunction as catalyst and hydrogen as reducing agent. The catalytic reaction rate improved 6.5 times under the simulated sunlight compared to the counterpart without light irradiation, and the TOF value of the catalytic reaction achieved as high as 7315 h−1 under light irradiation, better than the previously reported results. Further mechanism investigations indicate that light illumination can promote the activation of hydrogen and nitrobenzene molecules so that the catalytic performance improves significantly. This finding not only develops a green approach for the hydrogenation of nitroaromatics but also opens an avenue for designing high-efficiency photocatalysts.

The chemical adsorption effect of surface enhanced Raman spectroscopy of nitrobenzene and aniline using the density functional theory

Nitrobenzene and Aniline are representatives of the nitro or amino compounds of benzene, mainly used in the manufacture of dyes, spices, medicines, and so on. Extensive use of Nitrobenzene and Aniline may cause pesticide residue pollution and have carcinogenic effects on organisms. In this paper, the Nitrobenzene and Aniline single molecules and their complexes with gold nanoparticles are studied theoretically by Raman spectroscopy, the surface-enhanced Raman spectroscopy (SERS) and the density functional theory (DFT) simulations. Selective binding of gold nanoparticles (AuNPs) to the analyte was used to study the molecular electrostatic potential (MEP), frontier molecular orbital (FMO) and the Raman activity spectra of Nitrobenzene and Aniline, as well as the Raman activity spectrum of the complexes. The most electronegative sites of Nitrobenzene and Aniline are found in the MEP and the hypothesis that these sites might be the adsorption sites of Nitrobenzene/Aniline molecules at the gold surface. At the same time, the MEP of the Nitrobenzene/Aniline complexes also prove the existence of the charge transfer effect between Nitrobenzene/Aniline and Au. The FMO energy gap of Nitrobenzene/Aniline is 0.18983 eV and 0.18953 eV, respectively, and which, after adding the Au3 clusters, change to 0.03376 eV and 0.0797 eV, respectively, indicating that the Nitrobenzene/Aniline-Au3 complexes have stronger chemical activities and are more prone to the charge transfer effects. The electrophilic indices of Nitrobenzene (0.17921 eV) and Aniline (0.05635 eV) are calculated and analyzed, as well as that of Nitrobenzene/Aniline-Au3 complexes after adding the Au3 atomic clusters, 0.80819 eV and 0.19819 eV, respectively. The obvious increasing trend in the electrophilic indices of the Nitrobenzene/Aniline-Au3 complexes indicate their stronger biological activities and more prone to chemical reactions. The chemisorption of Nitrobenzene/Aniline and gold nanoparticles complexes is studied by the SERS, and the Raman formation of the complexes at different binding sites of Nitrobenzene/Aniline and Nitrobenzene/Aniline-Au3 is well explained by the surface selection rule. The reason for the selective enhancement of the spectral peaks presented in the Raman activity spectrum is calculated, and the enhancement factor of the chemical enhancement due to the charge transfer effect is calculated as well. The reason for the peak offset in the SERS spectrum to the conventional Raman spectrum is explained.

Photocatalytic membrane for in situ enhanced removal of semi-volatile organic compounds in membrane distillation under visible light

Membrane distillation (MD) is emerging as a promising technology for wastewater reclamation to relieve the shortage of freshwater. However, due to the contamination of semi-volatile organic compounds (s-VOCs), part of s-VOCs would transfer the membrane and impact the permeate quality during the MD process. Herein, an innovative AgCl/MIL-100(Fe)/PTFE photocatalytic membrane (AM/PTFE) was rationally synthesized in view of the increasing s-VOCs rejection. The AM/PTFE membrane was applied in the photocatalytic direct contact membrane distillation (DCMD) system and nitrobenzene (NB) was selected as the model contamination for evaluating removal performance of s-VOCs under visible light. Compared with the MD process, NB removal rate increased from 63.44% to 87.84% in the photocatalytic MD system. Moreover, stable performance was maintained over five NB removal cycles experiment with s-VOCs rejection higher than 84.84% in the end. The enhanced rejection of s-VOCs could be attributed to the combination of adsorption and photocatalytic. The volatile NB molecules were adsorbed on the surface of photocatalytic membranes, and the photo-electrons (e-) generated by immobilized nanomaterials could effectively remove pollutants under visible light irradiation. This photocatalytic MD system provides an attractive avenue for the water reclamation from s-VOCs contaminated wastewater in the practical applications.

Effects of different modifiers on the sorption and structural properties of biochar derived from wheat stalk.

Nitrobenzene is a widespread contaminant in water. Biochar (BC) is a promising material for removing organic pollutants, but the adsorption capacity of pristine BC is low. Chemical modification is often used to improve the adsorption performance, but information on the sorption of nitrobenzene by modified BC is rare. In this study, BCs pyrolyzed at 300, 500, and 700°C were modified by hydrochloric acid (HCl), sulfuric acid (H2SO4), sodium hydroxide (NaOH), hydrogen peroxide (H2O2), and nitric acid (HNO3), respectively. The properties, nitrobenzene sorption behaviors, and sorption mechanisms of different BCs were analyzed. The results showed that chemical modification decreased the sorption of nitrobenzene on BCs pyrolyzed at 300°C, possibly due to the loss of the partition phase and the increase in polarity after modification. Regarding BCs pyrolyzed at 500 and 700°C, the NaOH and HCl modifications significantly increased the sorption capacity by 19% and 60%, 18%, and 41%, respectively, possibly due to the increase in surface area, available pores, and aromaticity, while HNO3 modification decreased the sorption capacity by 41% and 31%. Two reasons were probably responsible for the decrease: one was the decrease in surface area after HNO3 modification due to the destruction of pore walls and the continuity of holes; the other was the strong repulsion between the nitro groups formed on the surface of BC and the nitro groups of nitrobenzene that drove nitrobenzene molecules away from the surface. A principal component-based comprehensive evaluation of the BC properties, which were significantly correlated with the sorption isotherm parameters, was used to evaluate the nitrobenzene sorption performance of the modified BC. Overall, BC pyrolyzed at 700°C modified with NaOH or HCl were proposed as effective sorption materials for the removal of nitrobenzene in environment, which also provided a chemical modified method of biochar derived from agricultural waste.

Detection of nitrobenzene in pristine and metal decorated 2D dichalcogenide VSe2: Perspectives from density functional theory

An efficient and reversible sensor for detecting nitrobenzene (NB) is the need of the hour due to its high toxicity and hazardous properties. We explore the transition metal (TM) decorated 1T VSe2 (where TM = Ag, Au, Pd and Ti) for its capability to sense NB by First Principles investigations. The underlying mechanisms for the interaction of TM on VSe2 and subsequently, NB on TM decorated VSe2 are investigated by studying the respective orbital interactions, thedensity of states analysis, and charge transfer studies. Practical feasibilities of the system concerning stability and potency for rapid recovery have also been explored by ab initio Molecular Dynamics simulations and recovery time calculations. Metals got bonded on VSe2 due to charge transfer from metal to VSe2. The adsorption of NB on VSe2 and metal doped VSe2 is due to charge gain by the NB molecules. From the adsorption energy and charge transfer analysis, we predict that Pd decorated VSe2 is the best systemamong the four metals on VSe2 considered. Pd is bonded strongly on VSe2 with abinding energy of -2.5 eV, and theVSe2+Pd system is stable at room temperature, as seen from Ab-initio MD simulations. NB is adsorbed on VSe2+Pd with suitable adsorption energy of -0.77 eV due to charge transfer of 0.17e from Pd 4d orbitals to 2p orbitals of O atoms of NB. From our extensive Density Functional Theory analysis, we firmly believe that Pd decorated VSe2 is a promising NB sensing materialthat may be fabricated experimentally.

Dissociative electron attachment to fluorinated nitrobenzenes

Low-energy electron attachment to three fluorinated nitrobenzene molecules in the gas phase in the energy range from zero to 10 eV is reported. Non-dissociative and dissociative electron attachment to 3,5-difluoronitrobenzene, 2,3,4-trifluoronitrobenzene and 2,4,6-trifluoronitrobenzene were observed. The experiments were carried out utilizing a trochoidal electron monochromator coupled to a time-of-flight mass spectrometer. Quantum chemical calculations of the major dissociation pathways have been made to compare thermochemical reaction balances with the experimental findings. The most dominant fragmentation channels involve (partial) dissociation of the nitro group, which is influenced by the fluorination of the molecule. In addition to prompt dissociation in the interaction region, slower metastable fragmentation of the nitro groups via loss of a neutral NO was also observed on microsecond timescales. Remarkably, we also observe the formation of the parent anion of 3,5-difluoronitrobenzene at non-thermal energies.

Construction of Cu nanoparticles embedded nitrogen–doped carbon derived from biomass for highly boosting the nitrobenzene reduction: An experimental and theoretical understanding

The state-of-the-art of the catalysis area prefers the construction of highly efficient, stable and low-cost catalysts based on facile and green synthesis procedures with biomass as the precursor. In this respect, we report the preparation of uniform Cu nanoparticles embedded nitrogen–doped carbon catalyst assisted by the carbonization of cushaw and Cu salt without additional reagents. Among the series of catalysts, the one pyrolized at 800 °C is a promising candidate for the liquid-phase reduction of nitrobenzene (NB) in the presence of NaBH4, showing superior reactivity and robust stability. Both experimental studies and DFT calculations reveal the strong mutual interaction between Cu nanoparticles and neighboring carbon layer accompanied by the interfacial electron transfer and generation of Cu-Nx species. This plays a key role in boosting the adsorption and activation of NB molecules. This study provides new insights for the high-value use of abundant and cheap biomass in advanced catalysis, and sheds light on the interfacial catalysis in driving the NB reduction reaction and beyond.

Role of the biochar modified with ZnCl2 and FeCl3 on the electrochemical degradation of nitrobenzene

The Zn/Fe-modified biochar on nitrobenzene (NB) removal during the electrolysis was investigated in this study. Both the Fe and Zn-modified biochar enhanced the NB adsorption compared with the un-modified biochar due to their greater specific surface area and more abundant surface function groups, respectively. The electrolysis under 2–11 V with the assist of both Fe/Zn-modified biochar achieved effective NB removal (>93%). The removal rate under 2 V using Zn/Fe-modified biochar (∼94%) was higher than that of the un-modified biochar (∼80%), whereas the removal was similar for those under 5, 8 and 11 V. The NB removal under 2 and 5 V was attributed to both adsorption and electrochemical decomposition of NB molecules. Electrolysis under 5 V by Fe-modified biochar had a higher degree of NB mineralisation than that using un-modified and Zn-modified biochar. This was likely that the Fe-modified biochar exhibited higher electrocatalytic properties, facilitating the further NB mineralisation. The ∙OH played significant roles in the degradation of NB by Fe-modified and un-modified biochar but did not significantly participated for the test using Zn-modified biochar. This was possibly because the Zn-modified biochar could adsorb greater amounts of ∙OH into the inner pores of Zn-modified biochar via its greater porosity and specific surface area, which may prevent the contact between ∙OH and NB molecules.