Unravelling the role of pore structure of biomass-derived porous carbon in charge storage mechanisms for supercapacitors.

This study presents findings on the production and analysis of activated carbon (AC), which exhibits a significantly expansive surface area derived from readily available and inexpensive agroforestry waste, specifically coconut shells. The carbon materials displayed encouraging features for electrochemical energy storage applications with a high specific surface area (2920 m2 g-1), an ordered mesoporous structure (∼2.5 nm), and substantial electronic conductivity. By altering the surface properties of AC materials, they exhibited different energy storage responses while using an ionic liquid as an electrolyte. Electrodes composed of AC sourced from coconut shells demonstrated notably high specific capacitance (78 F g-1) and retained capacitance when assessed within symmetric electrical double-layer capacitors (EDLCs) employing organic electrolytes. Interestingly, the AC cell in an organic electrolyte delivered a specific energy (Es) of 67 W h kg-1 at a specific power (Ps) of 1237 W kg-1 at the current density of 1 A g-1 and still provided Es of 64, 60, 58, 57, and 52 W h kg-1 at Ps of 2477, 3724, 4971, 6218 and 12 480 W kg-1 at the current density of 2, 3, 4, 5 and 10 A g-1. This work demonstrates the effect of different pore volumes on the electrocatalytic activity of AC derived from natural product waste. Our results indicate the feasibility of employing these electrodes for lab-scale applications. Thus, the AC material emerges as a highly promising substance, poised to advance the creation of cost-efficient, environmentally sustainable, high-performance, high-power devices.

Facile synthesis of ZnMoO4/AlPO4-5 nanorod composites as visible-light-driven photocatalysts and high-performance energy storage materials.

The present article describes the facile one-step hydrothermal synthesis of single-crystalline ZnMoO4/AlPO4-5 nanorod composites. The physicochemical properties of the synthesized materials, such as structure, morphology, and bandgap, were determined using techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption-desorption isotherms, X-ray photoelectron (XPS), ultraviolet-visible (UV-vis), and photoluminescence (PL). The XRD pattern of synthesized ZnMoO4/AlPO4-5 verifies the synthesis of nanocomposites. Diffuse UV-vis spectra reveal that ZnMoO4/AlPO4-5 nanorod composites exhibit an indirect semiconductor with an optical bandgap between 3.15 and 3.7 eV depending on Mo : Zn ratio. In comparison to pure AlPO4-5, ZnMoO4/AlPO4-5 nanocrystal composites showed significantly higher photocatalytic activity for the degradation of para-nitrophenol (PNP, 0.04 g l-1), with 14, 99, 70, and 54% for AlPO4-5, Mo : Zn (2)/AlPO4-5, Mo : Zn (4)/AlPO4-5, and Mo : Zn (6)/AlPO4-5, respectively. This result might be attributed to the composite's efficient charge transfer and optimized electron-hole pair recombination. The supercapacitive ability of ZnMoO4/AlPO4-5 nanorod composites was also investigated in this work. For the prepared electrodes using AlPO4-5, Mo : Zn (2)/AlPO4-5, Mo : Zn (4)/AlPO4-5, and Mo : Zn (6)/AlPO4-5, the capacitance values were 400, 725, 450, and 481.25 F g-1, respectively, at a current density of 0.5 A g-1. This study shows that ZnMoO4/AlPO4-5 nanorod composites are a potential visible-light-responsive photocatalyst. The electrochemical results further demonstrate the high capacitance of ZnMoO4/AlPO4-5 nanorod composites toward energy-storage applications.

Assessment of polyethylene/Zn-ionic as a diesel fuel sulfur adsorbent: gamma radiation effect and response surface methodology.

Irradiated waste high-density polyethylene@Zn/ionic liquid novel composite well-fabricated via coacervation method was irradiated by gamma-irradiation and studied the effect of that radiation on the desulfurization process. The prepared composites were characterized by various analytical techniques as follows: X-ray diffraction (XRD), Fourier-Transform infrared (FT-IR), X-ray photoelectron spectrometer (XPS), scanning electron microscope (SEM), High Resolution Transmission Electron Microscopy (HRTEM), N2-adsorption-desorption isotherm, and thermal gravimetric analysis (TG/DTA). The adsorptive desulfurization process of benzothiophene (BT) and dibenzothiophene (DBT) which are harmful compounds in diesel model fuel was investigating using the irradiated and unirradiated composite. The results illustrated that the unirradiated and irradiated composites exhibit an adequate adsorption capacity reached (50-75 mg S/g) and (60-85 mg S/g) for BT and DBT, respectively. The adsorption process over the prepared adsorbents follows the pseudo-second-order kinetic models. The irradiated composite exhibited more adsorption capacity than the unirradiated one due to the radiation generated more surface area and created proton-bond donor sites in the composite surface, which increases the interaction between the surface and sulfur species. The adsorption capacity and adsorption percentage for irradiated and unirradiated composites towards (SCCs) were studied using response surface methodology based on the central composite design (CCD). The thermodynamic factors (∆H°, ∆G°, and ∆S°) reveal that these processes are endothermic adsorption processes. The irradiated PEt @Zn/IL was re-used without significant loss of adsorption activity. This novel irradiated PEt @Zn/IL is the first time used as an adsorbent with an advantage that includes its excellent adsorption capacity, which ensures the product will be efficient in a real process such as the petrochemical industry.

Oxidative coupling of bio-alcohols mixture over hierarchically porous perovskite catalysts for sustainable acrolein production.

The acrolein production from bio-alcohols methanol and ethanol mixtures using AMnO3 (since A = Ba and/or Sr) perovskite catalysts was studied. All the prepared samples were characterized by XRD, XPS, N2 sorption, FTIR, Raman spectroscopy, TEM, SEM, TGA, and NH3-CO2-TPD. The catalytic oxidation reaction to produce acrolein has occurred via two steps, the alcohols are firstly oxidized to corresponding aldehydes, and then the aldol is coupled with the produced aldehydes. The prepared perovskite samples were modified by doping A (Sr) position with (Ba) to improve the aldol condensation. The most catalytic performance was achieved using the BaSrMnO3 sample in which the acrolein selectivity reached 62% (T = 300 °C, MetOH/EtOH = 1, LHSV = 10 h-1). The increase in acrolein production may be related to the high tendency of BaSrMnO3 toward C-C coupling formation. The C-C tendency attributes to that modification have occurred in acid/base sites because of metal substitution.