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[Display omitted] • A facile dual physico-chemical activation strategy is proposed. • The synthesized NPHPC possesses high specific surface area, pore volume, specific capacitance and excellent hydrophilicity. • The NPHPC delivered a splendid desalination capacity and good cycling stability. The preparation of heteroatom-doped hierarchical porous carbons (HPCs) possessing both high-performance and cost-effective is advantageous for the advancement of capacitive deionization (CDI). Biomass, which is abundant and inexpensive, has been widely utilized as a precursor for carbon electrodes. However, the simple pyrolysis of a single biomass typically leads to insufficient porosity with narrow surface area, along with poor wettability and conductivity, thereby resulting in limited desalination performance. Therefore, we employ ammonium dihydrogen phosphate (NH 4 H 2 PO 4) and potassium carbonate (K 2 CO 3) as chemical and physical activators, respectively, to co-activate lotus petiole (LP) for the preparation of N/P co-doped hierarchical porous carbon (NPHPC). In comparison with conventional single K 2 CO 3 activation, NPHPC prepared through dual physico-chemical activation exhibits exceptional specific surface area (S BET , 2170.00 m2/g), excellent pore volume (V pore , 1.16 cm3/g), outstanding mesoporosity (V meso /V pore , 72.41 %), superior hydrophilic performance (contact angle: 39°), high specific capacitance (221.86F/g), moderate N-doping (3.1 %) and P-doping (0.4 %). When assembled for desalination, the synthesized materials demonstrate a fabulous electroadsorption capacity of 21.85 mg/g together with notable cycling stability, highlighting their excellent application prospects. In summary, this work presents innovative ideas in proposing a facile synthesis of high-performance heteroatom-doped HPCs for CDI desalination. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green activation-self-activation strategy was proposed to prepare GO-inbuilt ENHPCs. • The splendid SAC of 17.86 mg/g and rapid ASAR of 0.99 mg/g/min for Ni2+ were gained. • The potential for eliminating NaCl, MgCl 2 , CaCl 2 and Ni2+ wastewater was evaluated. • Micro-mesoporous structure and copious active sites accelerated ion removal. Capacitive deionization (CDI) is considered a polar-promising technology to remove heavy-metal ions from wastewater. Herein, a green activation-self-activation strategy was exploited to build graphene (GO)-inbuilt mesopore-dominated N-doped hierarchical porous carbons (ENHPCs) using sodium lignosulfonate (SLS) as carbon sources/self-activators. Different from SLS self-activation and K 2 C 2 O 4 -SLS activation-self-activation, ENHPC LKG gained via GO-mediated K 2 C 2 O 4 -SLS activation-self-activation showed suitable mesopore-dominated micro-mesoporous structures with high surface area of 1795.5 m2/g, large mesoporous volume of 0.87 m3/g, 3.65 % N-doping and excellent conductivity. Its unique hierarchical porous structure and abundant active sites facilitated the ion rapid insertion and extraction. When utilized to capture low-concentration nickel (Ni2+) ions, ENHPC LKG delivered splendid salt removal capacity of 17.86 mg/g, rapid average salt removal rate of 0.99 mg/g/min and standout cycle stability. Meanwhile, ENHPC LKG was further extended to remove NaCl, MgCl 2 , CaCl 2 and Ni-containing wastewater, showing superior CDI property. Moreover, the recycled ENHPC LKG (10th) taken to eliminate indomethacin (IDM) depicted a splendid adsorption capacity. This work proved the significant applicant potential of the novel and green ENHPC LKG for disposing of Ni2+ ions via CDI technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped La 2 CuO 4 had been synthesized using melamine as the N precursor. • N-doped La 2 CuO 4 showed enhanced catalytic activity and stability. • Density Functional Theory (DFT) calculations were performed to verify the results. • A mechanism of phenol degradation was proposed. • The toxicity of degradation intermediates was greatly reduced. Herein, N-doped perovskite La 2 CuO 4 (LCO) (N-LCO(M)) was fabricated by sol–gel rapid calcination method using melamine (M) as N source/ligand, and applied for the catalytic wet air oxidation (CWAO) to degrade high-concentration phenol-containing simulated wastewater. The experimental results exhibited that N-LCO(M) illustrated enhanced phenol degradation efficiency. Thereinto, 87.9% COD degradation efficiency was achieved in simulated wastewater containing 8000 mg/L phenol, while for undoped LCO prepared with citric acid (CA) as ligand (LCO(CA)) was only 43.8%. The systematic characterizations and density functional theory (DFT) calculations were utilized to verify the above results. The results revealed that N doping favored the formation of more oxygen vacancies (*) and facilitated the charge transfer between Cu and O. More oxygen vacancies (*) reinforced the ability of N-LCO(M) to adsorb O 2 to form reactive oxygen species (O*), and meanwhile, the charge transfer between Cu and O was manifested as the redox cycle of the catalytic active metal Cu2+/Cu1+. The redox cycle also promoted the formation of O 2 − and HO, making the more exhaustive degradation of phenol. This successfully proved that N doping was core to improving the activity and stability of N-LCO(M). Moreover, a possible mechanism of phenol degradation was proposed based on the experimental results and DFT calculations. Eventually, the toxicity of the intermediate products was further evaluated by quantitative structure–activity relationship (QSAR) analysis, showing the significantly reduced toxicity of the intermediate products. Overall, the proposed CWAO technique is a green and promising wastewater treatment method. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrate-mediated organic salt activation strategy was proposed to fabricate high-yield-high-performance NHPC. • Tertiary porous structure and surface-exposed active sites facilitated salt ion removal. • The splendid desalination capability and rapid desalination kinetics were acquired. • The universality and commerciality for NHPCX y were further investigated. Developing a green and facile strategy for high-yield preparing N-doped hierarchical porous carbon (NHPC) for capacitive deionization (CDI) is a huge challenge for desalination. So far, there are limited reports on high-yield NHPC synthesis. Herein, a novel nitrate (NaNO 3 , KNO 3 , Zn(NO 3) 2 and NH 4 NO 3)-mediated-organic salt activation strategy was exploited to construct NHPCX y (X = Na, K, Zn, NH 4 ; Y(nitrate ratio) = 1, 3, 5). Thereinto, C 6 H 5 K 3 O 7 served as activator and nitrate acted as assisted-activator and foaming agent. Compared with C 6 H 5 K 3 O 7 activation, NHPCNa 3 acquired by NaNO 3 -C 6 H 5 K 3 O 7 co-activation achieved 35.5% high yield and depicted 3D macroarray structures with high specific surface area (S BET) of 1912.2 m2/g, large pore volume (V pore) of 1.56 cm3/g and 1.21 % N content. Its tertiary pore structure and rich surface-exposed active sites favored the ions rapid insertion and extraction from the micropores. The final NHPCNa 3 delivered an excellent salt adsorption capacity (SAC) of 19.74 mg/g. Moreover, it exhibited 14.61 mg/g high SAC at 15.5 mg/cm2 and only showed 9.4% SAC drop after 50 cycles. While using diverse biomass precursors, it obtained an optimal SAC of 23.16 mg/g. NHPCK 3 , NHPCZn 3 and NHPC(NH 4) 3 also presented the feature of high-yield-high-performance. The high yield came from the foaming effect of nitrate and the property difference may be ascribed to the different cations. This work provides one span-new green universality strategy to design high-yield-high-performance NHPCs in commercial-grade CDI applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A composite PMS activator of S-doped g-C 3 N 4 /NiCo 2 O 4 was obtained. • S doping widens the difference in the work functions of CNS and NCO. • Enhanced BIEF promotes the directional transfer of electrons from CNS to NCO. • 1O 2 was formed mainly through SO 4 •−, •OH and •O 2 − conversion. Transition metal oxide-mediated heterogeneous peroxymonosulfate (PMS) activation on organic pollutant degradation has attracted much attention, where continuous redox cycling between high and low valence metal ions is the key step as it relates to the radical generation. Herein, a composite PMS activator of S-doped g-C 3 N 4 /NiCo 2 O 4 (CNS_NCO) was constructed and exhibited excellent tetracycline (TC) degradation performance with 96.9% removal efficiency within 30 min. Experimental and theoretical calculations indicated that S doping not only widened the difference in the work function of CNS and NCO, but also enhanced the built-in electric field intensity of CNS_NCO heterojunctions, resulting in more electron transfer from CNS to NCO in a directional manner and accelerating the Co(III)/Co(II) and Ni(III)/Ni(II) redox cycle to form more reactive oxygen species (ROS). It was demonstrated that 1O 2 (main ROS) was formed mainly through SO 4 •−, •OH and •O 2 − (minor ROS) conversion. Meanwhile, high-valent cobalt-oxo (CoIV = O) species also played an important role in TC degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sustainable and facile self-activation strategy is proposed to synthesize high N-doped hierarchical porous carbon (HNHPC) for CDI. • The synthesized HNHPC PUA possesses ultrahigh specific surface area (3280.16 m2/g), splendid pore volume (2.49 cm3/g), large mesopore ratio (57.83%) and high N content (6.4%). • The small hierarchical porous carbon nanogranlue structure of HNHPC PUA helps to expose more accessible and extra active sites, accelerating the ions insertion and extraction from the micropores. • The HNHPC PUA delivered a splendid desalination capacity of 24.86 mg/g and good cycling stability. High N-doped hierarchical porous carbon (HNHPC) with ultrahigh BET surface area (S BET) and pore volume (V pore) has attracted great attention in capacitive deionization (CDI) due to the copious active sites. However, the traditional methods often adopt strong corrosive activators and fail to achieve high N-doping, which are harmful for its practical application. Herein, we develop a sustainable CO(NH 2) 2 -C 6 H 5 O 7 (NH 4) 3 -co-assisted C 6 H 5 K 3 O 7 (U-A-co-assisted P) self-activation strategy to prepare ultrahigh S BET and V pore HNHPCs for CDI desalination. Compared to the single P self-activation and U/A-assisted P self-activation, HNHPC PUA acquired via U-A-co-assisted P self-activation possesses ultrahigh S BET (3280.16 m2/g), splendid V pore (2.49 cm3/g), high V meso /V pore (57.83%) and high N-doping (6.40%). Its small hierarchical porous carbon nanogranlue structure helps to expose more accessible S BET and extra active sites, accelerating the ions insertion and extraction from the micropores. The resultant HNHPC PUA delivers a high specific capacitance of 203.9F/g. In the assembled CDI setup, HNHPC PUA exhibits a superior salt adsorption capacity (SAC) of 24.86 mg/g, a rapid salt adsorption rate (SAR) of 8.29 mg/g/min and reaches 88.7% SAC retention after 50 cycles in 500 mg/L NaCl at 1.2 V, suggesting good application potential. Overall, this work provides new insight into rapidly preparing ultrahigh S BET and V pore HNHPCs for energy and environmental applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • N-doped 3D hierarchical porous carbons (3DNHPCs) are prepared in a green strategy. • Tertiary porous structure and surface-exposed active sites accelerate ion insertion. • Superior desalination capacity and rapid desalination rate are achieved. • Ultrahigh water recovery and productivity are acquired. Exploiting a sustainable and effective strategy for fabricating 3D N-doped hierarchical porous carbon (3DNHPC) for capacitive deionization (CDI) is a huge challenge for desalination. The traditional methods often adopt expensive precursors, complex routes and strong corrosive activators that are harmful for its practical application. Herein, a novel green double organic salt activation strategy is developed that utilizes lotus stem (LS) with a regular 3D macroarray structure to acquire 3DNHPC x. Different from single C 6 H 5 K 3 O 7 or Na 2 EDTA activation, 3DNHPC x obtained under double organic salt co-activation exhibits a suitable micro-meso-macro porous structure with a high BET surface area (S BET) of 2256.2 m2/g, a large pore volume of 1.02 cm3/g, a remarkable mesoporous volume of 0.41 cm3/g and 1.31 % N content. Its unique tertiary pore structure and copious surface-exposed active sites facilitate the ions rapid insertion and extraction from the micropores. The assembled CDI cells achieve a superior salt removal capability of 25.36 mg/g as well as a splendid volumetric adsorption capacity (VAC) of 6.21 mg/cm3 and an ultrafast average salt removal rate of 7.84 mg/g/min. Meanwhile, 3DNHPC 11 maintain 89.4 % adsorption capacity after 50 cycles. Besides, 3DNHPC 11 obtains a high water recovery (WR) of 82.2 % and high productivity of 290 g NaCl /g C /(h m2) or 108.1 g NaCl /cm3 C /(h m2). This work sheds light on one way to design economical and eco-friendly 3DNHPCs for high-performance CDI desalination. [ABSTRACT FROM AUTHOR]

Ultrasensitive explosive sensors are significant in anti-terrorism and related environment issues. Herein, we proposed a novel boron-doped graphene (B-GE) modified glassy carbon electrode (GCE) applied as a simple, sensitive electrochemical high melting explosive (HMX) sensor. The morphology and structure features of B-GE were characterized. The electrochemical behaviors of HMX on the B-GE modified GCE were investigated by cyclic voltammetry (CV). Under the optimized conditions, CV was used for the quantitative detection of HMX, and the reduction peak current exhibited good linear dependence with the concentration of HMX in the ranges of 2 ∼ 20 μM and 20 ∼ 100 μM. The low detection limit (LOD) was calculated as 0.83 μM (245.81 ppb). Furthermore, the B-GE/GCE showed satisfactory repeatability, high selectivity and stability. The reduction reaction mechanism of HMX on B-GE modified electrode was explored by computational theoretical analysis. Additionally, the differences of the reduction mechanisms from nitroaromatic explosives were discussed. [ABSTRACT FROM AUTHOR]

In the present work, the N-doped fluorescent carbon nanomaterials (NCMs) were prepared. Fe3+ quenched the fluorescence of NCMs effectively, while the addition of different concentrations of ATMP or DTPMP can restore the fluorescence intensity of NCMs to different degrees. Therefore, the Fe-NCMs fluorescent probe can quantitatively detect ATMP or DTPMP, and the detection limit (LOD) of ATMP and DTPMP was 0.479 μΜ and 0.254 μΜ, respectively. The fluorescence quenching mechanism of NCMs by Fe3+ was revealed by UV–vis absorption spectra and the fluorescence lifetime analysis, the results showed that the fluorescence quenching was a combination of static and dynamic quenching. Moreover, based on Density Function Theory (DFT) calculation, basin analysis, topology analysis of atoms in molecules (AIM), electron localization function (ELF) analysis, and bond order density (BOD) analysis were firstly combined to reveal the difference in fluorescence restoration degree between the two organic phosphonates on Fe-NCMs. The detection mechanism of ATMP and DTPMP by Fe-NCMs was explained from a microscopic point of view. • Fe-NCMs were first applied in the detection of organophosphates. • Fe-NCMs had high selectivity and sensitivity for ATMP and DTPMP. • The micro-mechanism of fluorescence detection was revealed. • Wave function analysis based on quantum chemistry theory was first applied. [ABSTRACT FROM AUTHOR]

Poly(3-methylthiophene)/nitrogen doped graphene modified glassy carbon electrode (P3MT/NGE/GCE) was prepared through simple drop-casting of NGE, followed by the electrodeposition of P3MT film for sensitive electrochemical determination of trace amounts of pesticide phoxim. The morphology and structure of P3MT/NGE/GCE were characterized by scanning electron microscopy; the electrochemical behavior of P3MT/NGE/GCE was investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and chronocoulometry. The preparation conditions of modified electrode, the dropping amount of NGE and polymerization laps of P3MT, were optimized. Under the optimized conditions, the reduction peak current of cyclic voltammetric curve varied linearly with the concentration of phoxim over the two linear ranges of 0.02–0.2 μM and 0.2–2.0 μM, and the low detection limit was 6.4 nM according to lower linear range (S/N = 3). The sensor also exhibited excellent selectivity to phoxim over a wide range of possible interferents including ions, biomolecules, common environment pollutants and widely-used organophosphate pesticides. Moreover, the satisfactory practical feasibility of the sensor was evaluated by the environmental phoxim measurements. [ABSTRACT FROM AUTHOR]

Polycarbazole (PCZ)/nitrogen-doped graphene (N-GE) composite was prepared by electropolymerization of carbazole on the N-GE modified glass carbon electrode (N-GE/GCE) for fabricating a novel electrochemical sensor for 4-nitrophenol (4-NP). The PCZ/N-GE shows high conductivity and well-distributed nanostructure. The redox behavior of 4-NP at a PCZ/N-GE/GCE was investigated in acetate buffer solution by cyclic voltammetry (CV), compared with the bare GCE, reduced graphene oxide (RGO), N-GE and PCZ modified GCEs. The results indicate that all modified electrodes show the enhanced reduction peak currents. However, the PCZ/N-GE/GCE exhibits the highest peak current and most positive reduction potential of 4-NP, which reflects the PCZ/N-GE composite has the best electrocatalytic activity towards 4-NP. The enhanced electrochemical performance of PCZ/N-GE and the electrocatalytic activity to 4-NP are contributed to the synergic effect of PCZ and N-GE with highly conductivity and large surface area, which can greatly facilitate the electron-transfer processes between the electrolyte and electrode. An electrochemical sensor for 4-NP was developed based on the PCZ/N-GE modified electrode under the optimized conditions. The reduction peak current was linear with the concentration of 4-NP in the range of 8 × 10 -7 ∼2 × 10 -5 M. The low detection limit of the sensor was estimated to be 0.062 μM (S/N = 3). The sensor based on PCZ/N-GE/GCE was also applied to the detection of 4-NP in real water samples. [ABSTRACT FROM AUTHOR]

Highlights: [•] A PEDOT/GO modified electrode was obtained via potentiostatic method using GO as a dopant. [•] The electrochemical behavior of acetaminophen (AP) showed highly reversibility. [•] An electrochemical sensor based on PEDOT/GO was developed for the detection of AP. [•] The sensor shows high sensitivity and selectivity to AP. [ABSTRACT FROM AUTHOR]