Black phosphorus (BP) is a two-dimensional material that has gained attention for various applications due to its exceptional physical and chemical properties such as tunable bandgap and high charge carrier mobility. However, the critical step towards the application of BP is still contingent on successfully exfoliating the bulk material into few-layer phosphorene nanosheets. Herein, we show a one-step, facile, and environmentally friendly method of bipolar electrochemical exfoliation-and-deposition of BP nanosheets on a positive feeding electrode. The exfoliated-and-deposited material is high-quality phosphorene with an orthorhombic crystal structure, and it adheres onto the substrate with a fractal and structured morphology. The electrochemical performance of the material was evaluated in a symmetric two-electrode configuration soaked in aqueous electrolyte for capacitive energy storage application. The results revealed fractional-order capacitive behaviour in the low-to-medium frequency, and a high stability and reversibility for at least 40 000 cycles. The power performance is outstanding with 0.35 mW cm⁻² at a constant current rate of 0.5 mA cm⁻².

Black phosphorus (BP) as a rising star among 2D materials has attracted attention for a wide range of applications due to its fascinating properties. The key point for the real application of phosphorene depends on its exfoliation technique to produce high‐quality nanosheets. In recent years, tremendous efforts have been made in the preparation and energy storage application of phosphorene and phosphorene‐based hybrid electrodes. Herein, the state‐of‐the‐art liquid‐based exfoliation and characterization of phosphorene fabricated by sonication, anodic and cathodic electrochemical exfoliation, and bipolar electrochemical exfoliation in diverse solutions and conditions are discussed. In addition, the electrochemical properties and storage mechanism of phosphorene‐based electrodes for rechargeable batteries and supercapacitors are discussed. Finally, the challenges and opportunities of phosphorene nanosheets in terms of exfoliation and energy storage applications are addressed.

Application of biochars in agricultural soils has the potential to reduce groundwater contamination of atrazine, a widely used herbicide in the US, therefore sustaining environmental quality and reducing human health issues. This study was conducted to characterize biochars produced from six feedstocks and investigate their ability to remove and retain atrazine in an organic-rich soil. Australian pine (AP), Brazilian pepper (BP), coconut husk (CH), cypress (Cy), loblolly pine (L), and pecan shell (P) feedstocks were pyrolyzed at 350 °C and 500 °C. Adsorption and desorption behaviors of atrazine were explained using Freundlich isotherms. Higher pyrolysis temperature increased specific surface area (5 times), total pore volume (2.5 times), and aromaticity (1.4 times) of the biochars. CH feedstock produced the most effective biochars (CH350 and CH500), which adsorb 8–12% more atrazine than unamended soils. CH350 biochar performed the best (K_{d ads} = 13.80, K_OC = 153.63, K_{d des} = 16.98) and had significantly higher (p < 0.05) adsorption than unamended soil, possibly resulting from its highest cation exchange capacity (16.32 cmol kg⁻¹). The K_{d des} values for atrazine desorption were greater than the K_{d ads} for adsorption, indicating retention of a considerable amount of atrazine by the biochar-amended soils following desorption.

In this study, porous manganese oxide (MnO_x) thin films were synthesized via electrostatic spray deposition (ESD) and evaluated as pseudocapacitive electrode materials in neutral aqueous media. Very interestingly, the gravimetric specific capacitance of the ESD-based electrodes underwent a marked enhancement upon electrochemical cycling, from 72 F∙g⁻¹ to 225 F∙g⁻¹, with a concomitant improvement in kinetics and conductivity. The change in capacitance and resistivity is attributed to a partial electrochemical phase transformation from the spinel-type hausmannite Mn₃O₄ to the conducting layered birnessite MnO₂. Furthermore, the films were able to retain 88.4% of the maximal capacitance after 1000 cycles. Upon verifying the viability of the manganese oxide films for pseudocapacitive applications, the thin films were integrated onto carbon micro-pillars created via carbon microelectromechanical systems (C-MEMS) for examining their application as potential microelectrode candidates. In a symmetric two-electrode cell setup, the MnO_x/C-MEMS microelectrodes were able to deliver specific capacitances as high as 0.055 F∙cm⁻² and stack capacitances as high as 7.4 F·cm⁻³, with maximal stack energy and power densities of 0.51 mWh·cm⁻³ and 28.3 mW·cm⁻³, respectively. The excellent areal capacitance of the MnO_x-MEs is attributed to the pseudocapacitive MnO_x as well as the three-dimensional architectural framework provided by the carbon micro-pillars.

Surface modification is a reliable method to enhance the sensing properties of pristine graphene by increasing active sites on its surface. Herein, we investigate the interactions of the gas molecules such as NH₃, NO, NO₂, H₂O, and H₂S with a zinc oxide (ZnO)–graphene hybrid nanostructure. Using first-principles density functional theory (DFT), the effects of gas adsorption on the electronic and transport properties of the sensor are examined. The computations show that the sensitivity of the pristine graphene to the above gas molecules is considerably improved after hybridization with zinc oxide. The sensor shows low sensitivity to the NH₃ and H₂O because of the hydrogen-bonding interactions between the gas molecules and the sensor. Owing to observable alterations in the conductance, large charge transfer, and high adsorption energy; the sensor possesses extraordinary potential for NO and NO₂ detection. Interestingly, the H₂S gas is totally dissociated through the adsorption process, and a large number of electrons are transferred from the molecule to the sensor, resulting in a substantial change in the conductance of the sensor. As a result, the ZnO–graphene nanosensor might be an auspicious catalyst for H₂S dissociation. Our findings open new doors for environment and energy research applications at the nanoscale.

Energy Storage Devices In article number 2000148, Amin Rabiei Baboukani, Chunlei Wang, and co‐workers summarize the fundamentals and latest advances in liquid‐based exfoliation of black phosphorus i...