Ravishankar T N, Ananda A, Shilpa B M, Adarsh J R
Department of Chemistry, B.M.S. College of Engineering, Bull Temple Road, Basavanagudi, Bengaluru, Karnataka 560019, India.
Department of Chemistry, Dayananda Sagar Academy of Technology & Management Udayapura, Kanakapura Road, Bengaluru 560082, India.
R Soc Open Sci. 2025 Feb 12;12(2):241733. doi: 10.1098/rsos.241733. eCollection 2025 Feb.
Herein, NiO and Ag/NiO NPs were produced via the solution combustion method using nickel nitrate and silver nitrate as oxidizers and water as a fuel at 450°C. The study also explores their applications in photocatalytic dye degradation, H production and antibacterial properties. The primary advantage of using water as a green fuel in the solution combustion method is that it serves a dual purpose-both as a fuel and as a solvent. . X-ray diffraction confirmed the existence of Ag in the bunsenite form of rhombohedral structure with a simple cubic system, with particles sized at 31-44 nm. Energy-dispersive X-ray spectroscopy revealed Ni, O and Ag weight percentages of 48.2, 44.5 and 7.3%, respectively. X-ray photoelectron spectroscopy confirmed the formation of Ag in NiO nanostructure. UV-visible spectrometry showed reduced band gap energy of Ag/NiO NPs (3.03-2.87 eV) compared to the bare NiO NPs (3.21 eV), red shift of the optical response towards the visible region after doping Ag into the NiO. The 0.3 wt% Ag/NiO NPs showed the highest quantum efficiency (0.781) among the other synthesized NPs. Fourier-transform infrared spectroscopy revealed absorption bands in the range of 460-900 cm stretching vibrations of Ni-O and Ag-O. Photoluminescence spectroscopy indicated that a doping concentration of 0.3 wt% Ag effectively introduces donor levels, defect levels and surface trap states within the NiO nanocrystalline structure, enhancing charge carrier separation and reducing recombination. Scanning electron microscopy revealed a voluminous, porous surface morphology characterized by numerous voids, resulting from the release of various combustible gases during the combustion process. Transmission electron microscopy images showed that most particles were spherical, irregular in size and well-distributed, with minimal aggregation with an average particle size of 25.8 nm. BET analysis of both NiO and 0.3 wt% Ag/NiO NPs exhibited type IV adsorption isotherms, indicating mesoporous structures and a clear monolayer-multilayer adsorption process, 0.3 wt% Ag/NiO NPs showed the highest surface area (170 m g) compared to the NiO (130 m g) NPs. Ag/NiO NPs has demonstrated a promising H evolution rate of 1212 μmol g⁻¹ under visible light illumination in a water/ethanol system. The trypan blue dye degradation reaches up to 98% and has moderate stability for the reusable photocatalysis process. The synthesized NPs exhibited significantly enhanced antibacterial activity against a range of bacterial strains.
在此，通过溶液燃烧法，以硝酸镍和硝酸银作为氧化剂，水作为燃料，在450°C下制备了NiO和Ag/NiO纳米颗粒。该研究还探索了它们在光催化染料降解、氢气产生和抗菌性能方面的应用。在溶液燃烧法中使用水作为绿色燃料的主要优点是它具有双重作用——既是燃料又是溶剂。X射线衍射证实了在具有简单立方体系的菱面体结构的氧化镍矿形式中存在银，颗粒尺寸为31 - 44纳米。能量色散X射线光谱显示Ni、O和Ag的重量百分比分别为48.2%、44.5%和7.3%。X射线光电子能谱证实了在NiO纳米结构中形成了银。紫外可见光谱表明，与裸NiO纳米颗粒（3.21 eV）相比，Ag/NiO纳米颗粒的带隙能量降低（3.03 - 2.87 eV），在将Ag掺杂到NiO中后，光学响应向可见光区域发生红移。0.3 wt%的Ag/NiO纳米颗粒在其他合成的纳米颗粒中表现出最高的量子效率（0.781）。傅里叶变换红外光谱显示在460 - 900 cm范围内有吸收带，这是Ni - O和Ag - O的伸缩振动。光致发光光谱表明，0.3 wt%的掺杂浓度有效地在NiO纳米晶体结构中引入了施主能级、缺陷能级和表面陷阱态，增强了电荷载流子的分离并减少了复合。扫描电子显微镜显示出大量的多孔表面形态，其特征是有许多孔隙，这是由于燃烧过程中释放出各种可燃气体所致。透射电子显微镜图像显示，大多数颗粒是球形的，尺寸不规则且分布均匀，聚集极少，平均粒径为25.8纳米。对NiO和0.3 wt%的Ag/NiO纳米颗粒的BET分析均显示IV型吸附等温线，表明为介孔结构以及明显的单层 - 多层吸附过程，0.3 wt%的Ag/NiO纳米颗粒相比NiO（130 m²/g）纳米颗粒表现出最高的表面积（170 m²/g）。Ag/NiO纳米颗粒在水/乙醇体系中可见光照射下表现出有前景的1212 μmol g⁻¹的析氢速率。锥虫蓝染料降解率高达98%，并且对于可重复使用的光催化过程具有适度的稳定性。合成的纳米颗粒对一系列细菌菌株表现出显著增强的抗菌活性。
