A novel, “all-in-one”, multifunctional microsphere with a fluorescent mesoporous silica shell (Rhodamine B coordinate receptor inside) and a magnetic core (Fe₃O₄) has been successfully fabricated using a sol–gel method and small molecular (CTAB) surfactants as structure-directing agents. At the same time, they were examined for environmental protection applications to detect, adsorb and remove Hg²⁺ in aqueous solution. The prepared nanocomposite microspheres were fluorescent, mesoporous, and magnetizable, with a diameter of 300–450 nm, a surface area of 600 m² g⁻¹, a pore size of 2.5 nm, and a saturation magnetization of 27.5 emu g⁻¹. These multifuctional microspheres showed excellent fluorescence sensitivity and selectivity towards Hg²⁺ over other metal ions (Na⁺ , Mg²⁺ , Mn²⁺ , Co²⁺ , Ni²⁺ , Zn²⁺ , Cd²⁺ , Ag⁺ , Pb²⁺ and Cu²⁺ ). Upon the addition of Hg²⁺ , an overall emission change of 16-fold was observed, and the detection limit of Hg²⁺ was as low as 10 ppb. The adsorption process of Hg²⁺ on the microspheres was well described by the Langmuir equation. The equilibrium can be established within five minutes and the adsorption capacity was 21.05 mg g⁻¹. The concentration of Hg²⁺ ions can be reduced to less than 0.05 ppm and the used microspheres can be easily separated from the mixture by adding an external magnetic field. These results suggest that these “all-in-one” multifunctional nanocomposites are potentially useful materials for simultaneously rapidly detecting and recovering dangerous pollutants in aqueous solution.

2,5-Furandicarboxylic acid (FDCA), as an important monomer to produce biodegradable polymers, is a hot compound in the field of electrocatalysis. Designing high-activity and low-cost electrocatalysts for the production of high concentration FDCA is an urgent and challenging task. Here, a cactus-like NiCoP nanoplate was prepared as a robust electrocatalyst to enable 5-hydroxymethylfurfural (HMF) oxidation to FDCA at high concentration. In situ Raman spectroelectrochemical analysis investigated the dynamic structural evolution of the NiCoP surface during the electrooxidation of HMF. The substituted Co atoms make the NiOOH active species easier to form on the NiCoP surface than Ni₂P at low constant voltage, which promotes the oxidation of HMF into FDCA. The total potential of coupling the cathodic H₂ reduction reaction with the anodic HMF oxidation reaction (HMFOR) is only 1.464 V when NiCoP is the electrode material. The design of the flow-through mode reactor optimized the mass transfer process in the reaction, and further improved the coupling efficiency. The conversion rate of HMF and yield of FDCA reach 98.7% and 98.8%, respectively, even when the concentration of HMF is as high as 300 mM.

Hybrid hierarchically porous silica adsorbents were simply fabricated by the sol–gel method and modified with thiol or sulfonic groups. These materials with pores on both micrometre and nanometre scales exhibit a satisfactorily adsorptive property to various pollutants in water, including heavy metal ions (Hg²⁺ , Cd²⁺ , Pb²⁺ , Cu²⁺ , Ag⁺ and CrO₄ ^{2 −}) and organic compounds (dyes, biogenic amines, pesticides and amino acids). The thiol functionalized hierarchically porous silica micro-foam (SH-HSM), which has a low thiol content (0.66 mmol g⁻¹), shows significantly high adsorption capability to Hg²⁺ (140.1 mg g⁻¹) in particular. Then sulfonic acid-functionalized adsorbent (SO₃H-HSM) was obtained through direct oxidization of SH-HSM by H₂O₂ without destruction of the hierarchical structure. It was found that SO₃H-HSM could effectively remove organic compounds with positive charge in solution through electrostatic interactions. The adsorption capability of SO₃H-HSM for some basic dyes, such as fuchsin basic, could reach approximately 1145.2 mg g⁻¹. The mixture of SH-HSM and SO₃H-HSM showed good purifying capacity to simulate multicomponent wastewater, containing different inorganic and organic chemicals. The removal rate for any of the pollutants was more than 90%, and could even reach 100% for metal ions and dyes. The strong adsorption ability of these porous adsorbents may be due to the interwoven meso- and macroporous structures which can increase mass transport and easier accessibility for pollutants to the active sites.

Monolithic silica with macroporous skeleton and well-defined mesopores was prepared via sol–gel method by using triblock polymer P123 as the structure directing agent and tetramethoxysilane (TMOS) as the silicon source. The large macroporous channels (3 μm in diameter), formed by phase separation and sol–gel transition, ensure the substances diffuse in the bulk easily. Appropriate specific area (nearly 400 cm² g⁻¹) and mesopores (17.67 nm in diameter and 1.99 cm³ g⁻¹ in volume) supply enough space for storing the molecules absorbed. After grafting organic groups on their surface, hydrophobic monolithic hierarchically porous silica (MHS) could be prepared with high capability to adsorb oils and organic contaminants on the surface of water without coadsorption. In order to explore the factors impacting the ability of adsorption, a series of properties are characterized including the BET surface, porous size and water contact angle by changing the type and dosage of modifying agents. The maximum absorptive ability can reach 8 times the monolith's weight, and materials could be recycled more than 20 times by an easy treatment. Good selectivity, better thermal stability, easy removing and excellent recyclability for oil removal give the material potential applications.

A hierarchically porous monolith with macro- and meso-pores was synthesized via a sol–gel and phase separation process. Due to the surface modification by organic silanes, the wettability of the silica material was effectively controlled. A series of hydrophobic porous silica monoliths (HPSM) were obtained. Using a “reverse membrane emulsification” process, the HPSM not only cleared oil away from water, but also broke the micro-emulsion efficiently, even when emulsion stabilizer was in the system. As the filtration layer, 1.0 g of HPSM could treat 944 mL of oil containing water or 667 mL of surfactant-stabilized micro-emulsion. HPSM materials could remove at maximum 96.5% of the oil in water and 100% surfactant in the micro-emulsion. In addition, the material could be reused through a simple treatment. The excellent separating effect was kept even after 8 times of regeneration. Special selectivity, easy operation and excellent recyclability make the material have great potential for practical application.

Inspired by the structure and function of coral in nature, a series of composite electrode materials were prepared via depositing conducting polymers, such as polyaniline (PANi), polythiophene (PTh) and polypyrrole (PPY), on the surface of monolithic coral-like porous carbon (MC). MC with a specific surface area as high as 1125 m² g⁻¹ was prepared by a facile dual-templating approach. A thin layer of the conducting polymer was formed on the carbon surface. The constitutive properties including the morphology, pore size and specific area were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller measurement (BET), respectively. The electrocapacitive properties of electrode materials were evaluated using cyclic voltammetry and galvanostatic charge–discharge cycling in a three electrode system. Compared with MC, the specific capacitances of composite materials had an obvious shift, which reached 1488 F g⁻¹ at a high current density (1.0 A g⁻¹) in an aqueous H₂SO₄ electrolyte. The coral-like hierarchical porous structure of the carbon favoured the diffusion of the electrolyte ions, hence not only improving the energy storage capacity but also enhancing the power density. The energy density reached 49.5 W h kg⁻¹, even when the maximum power density was 12 000 W kg⁻¹. In addition, such a composite electrode material also showed considerable electrochemical stability, with at least 76.7% of the capacitance being retained after 1000 cycles.