Application of Copper Hydroxide Nanosheets Modified with Au@Pt Bimetallic Nanoparticles for Adsorption and Reduction of Hazardous Gas Pollutants

As environmental pollution increases, there is a growing need for materials that can effectively adsorb or reduce gas pollutants in the air. Here, we prepared composite materials comprised copper hydroxide nanosheets modified with a surfactant (sodium dodecylbenzenesulfonate or sodium oleate) and Au@Pt bimetallic nanoparticles and examined their adsorption and catalytic performance towards nitrogen acid (NOₓ) and carbon dioxide (CO2). Scanning electron microscopy and elemental distribution analysis confirmed that Au@Pt nanoparticles were uniformly dispersed and adsorbed on the nanosheet surface. X-ray diffraction and Fourier transform infrared analyses indicated that both surfactant and Au@Pt modification altered the crystal structure and surface chemical properties of the nanosheets. Modification with sodium oleate resulted in obvious broadening and partial disorder in the crystal structure, whereas further Au@Pt modification led to amorphous structural characteristics. Brunauer–Emmett–Teller measurements showed that both surfactant and Au@Pt modification reduced the specific surface area and pore volume of the material. In NOx adsorption tests, unmodified Cu₂(OH)₃(CH₃COO)·H₂O showed the highest adsorption, whereas samples modified with surfactants and Au@Pt nanoparticles exhibited reduced adsorption, indicating that the crystallinity and specific surface area have a decisive impact on adsorption efficiency. Additionally, in cyclic voltammetry measurements, Au@Pt nanoparticle-modified electrodes produced a higher cathode current under CO₂-saturated conditions and exhibited good electrocatalytic activity towards CO₂ reduction. We speculate that CO can be adsorbed on the Pt surface and participate in oxidation or undergo reduction with Cu₂(OH)₄, further improving the catalytic efficiency. These results provide key insights for pollutant control material design and biosensor device fabrication.