An economic low-temperature self-ignition solution combustion method was used to synthesize 1–11 mol% chromium ion (Cr³⁺) doped MgAl₂O₄ nanoparticles (NPs). The structural, morphological and energy gap variations due to the influence of Cr³⁺ on the host matrix were evidenced by powder X-ray diffraction (PXRD), Fourier transformed infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), and transmission electron microscopy (TEM). Under visible light irradiation, the as-prepared NPs showed excellent photocatalytic activities (PCA) for the industrial dye Acid Red-88 (AR-88) and pyrocatechol (PY) - an emerging pollutant (EP). The experiments were carried out at room temperature in an aqueous solution at a concentration of 20 ppm. Among others, MgAl₂O₄:Cr³⁺(5 mol%) showed 91.38% degradation within 150 min exhibiting zero-order kinetics and 82% degradation in 6 h displaying the first order kinetics for AR-88 dye and PY EP, respectively. In this case, a greater number of hydroxyl (OH^.) radicles dominate over other reactive oxygen species (ROS), such as holes and singlet oxygens (¹O₂) under different pH conditions. Electrochemical studies have yielded the proton diffusion coefficient (D) value as large as 2.145 × 10⁻⁴ cm²s⁻¹ for the optimized NP electrode, which is substantially greater than 1.0935 × 10⁻⁵ cm²s⁻¹ for the pure MgAl₂O₄ one owing to the intercalated anions and structurally disordered density of the electrode material. This superior electrochemical behaviour suggests the potential application of the optimized NP material as an anodic electrode for supercapacitors.

采用经济的低温自燃溶液燃烧法合成了 1-11 mol% 的铬离子 (Cr ³⁺ ) 掺杂的 MgAl ₂ O ₄纳米粒子 (NPs)。由于 Cr ³⁺的影响导致的结构、形态和能隙变化通过粉末 X 射线衍射 (PXRD)、傅里叶变换红外光谱 (FTIR)、漫反射光谱 (DRS) 和透射电子显微镜 (TEM) 证明了基质上的表面。在可见光照射下，所制备的 NPs 对工业染料酸性红 88 (AR-88) 和邻苯二酚 (PY) - 一种新兴的污染物 (EP) 显示出优异的光催化活性 (PCA)。实验在室温下在浓度为 20 ppm 的水溶液中进行。其中，MgAl ₂ O ₄ :Cr ³⁺ (5 mol%) 在 150 分钟内表现出 91.38% 的降解，表现出零级动力学，在 6 小时内表现出 82% 的降解，分别显示出 AR-88 染料和 PY EP 的一级动力学. 在这种情况下，更多的羟基（OH^. ) 基团在不同 pH 条件下优于其他活性氧 (ROS)，例如空穴和单线态氧 ( ¹ O ₂ )。电化学研究表明，优化的 NP 电极的质子扩散系数 (D) 值高达 2.145 × 10 ^-4  cm ² s ^-1，大大大于纯 MgAl 的1.0935 × 10 ^-5  cm ² s ^-1 ₂ O ₄一种是由于电极材料的嵌入阴离子和结构上无序的密度。这种优异的电化学行为表明优化的 NP 材料作为超级电容器阳极电极的潜在应用。