In this paper, carbon-matrix-supported copper (Cu) and cobaltous oxide (CoO) nanoparticles were obtained by using coordination polymers (CPs) as a precursor. The aqueous solutions of copper methacrylate (CuMA) and cobalt methacrylate (CoMA) were preferentially prepared, which were then mixed with anhydrous ethanol to fabricate dual metal ion coordination polymers (CuMA/CoMA). After calcination under an argon atmosphere, the Cu-CoO/C nanocomposite was obtained. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed that the material has banded morphology, and the dual functional nanoparticles were highly dispersed in the carbon matrix. The prepared material was used in a heterogeneous Fenton-like reaction, with the aim of replacing traditional ferric catalysts to solve pH constraints and the mass production of ferric slime. The obtained nanocomposite showed excellent catalytic performance on the degradation of methylene blue (MB) at near-neutral conditions; the discoloration efficiency is about 98.5% within 50 min in the presence of 0.15 mmol/mL H₂O₂ and 0.5 mg/mL catalyst. And good reusability was verified via eight cycles. The plausible pathway for MB discoloration and the possible catalytic mechanism was also proposed.

Mesoporous silica loaded with ultrasmall sized and highly dispersed CuO nanoparticles was synthesized based on an alkali-free strategy. The obtained silica material has excellent catalytic performance on reduction MB dye in the presence of NaBH₄ as reductant.

Herein, zinc oxide/graphite dual matrix supported cobalt material (Co@ZnO-Gr) was developed. The as-obtained material exhibits a well-defined ribbon-like morphology, with Co nanoparticles highly dispersed in ZnO-Gr composite matrix. This heterojunction structure endows the material with prominent adsorption capability and catalytic ability, enabling the high-efficiency removal of organic contaminants from wastewater. Acid Orange 7 (AO7) was employed as the model pollutant to assess the capability of Co@ZnO-Gr by varying key parameters including catalyst dosage, H2O2 concentration, pH, and the presence of different anions. The results showed that the removal efficiency approached 100% under near-neutral conditions (pH 5–9). The adsorption and catalytic behaviors were accurately modeled by pseudo-first-order kinetics, with the K values were 0.03415 min−1 and 0.1213 min−1, respectively. In addition to a marked effect of humic acid (HA) on AO7 removal efficiency, no significant interference was observed from other common anions (Cl−, F−, SO42−, NO3−, HPO42−), indicating the high selectivity and robustness of the system under complex ionic conditions. Radical scavenging results along with ESR spectra jointly confirmed the generation and involvement of ·OH, 1O2 and O2·− during the degradation process, with ·OH and O2·− being the dominant species. The formation of O2·− was attributed to the abundant oxygen vacancies in the material, which has been confirmed by XPS and EPR. Basing on the intermediate analysis and theoretical calculations, the degradation pathway of AO7 was deduced, along with the possible catalytic mechanism. Besides, the applications of this obtained material on other classes of contaminants and real wastewater were also detected.