The influence of doping amount on the catalytic oxidation of formaldehyde by Mn-CeO2 mixed oxide catalyst: A combination of DFT and microkinetic study

The removal of toluene by thermoscatalytic oxidation using CeO2-based catalysts:a review

Volatile organic compounds (VOCs) pose a serious threat to human health and the ecological environment. Thermal catalytic oxidation based on cerium dioxide based (CeO2-based) catalysts is widely used in the degradation of toluene. However, new problems and challenges such as how to reduce the energy consumption during catalytic oxidation, improve the anti-poisoning performance of catalysts, and enhance the multi-species synergistic catalytic ability of catalysts continue to emerge. On this basis, we systematically summarize the current status of research progress on the thermocatalytic oxidation of toluene based on CeO2-based catalysts. Firstly, we summarized the rules on how to improve the catalytic performance and anti-poisoning performance of CeO2-based catalysts; Secondly, we discussed the effect of light reaction conditions on the thermal coupled catalytic oxidation of toluene; In addition to this, we explored the current status of synergistic multi-pollutant degradation, mainly of toluene; Finally, we summarized the mechanism of catalytic oxidation of toluene by combining theoretical simulation calculations, in-situ infrared analyses, and other means. We present the promising applications of CeO2-based catalysts in the catalytic oxidation of toluene, and hope that these summaries will provide an important reference for the catalytic treatment of VOCs.

Synergistic activation of P and orbital coupling effect for ultra-sensitive and selective electrochemical detection of Cd(II) over Fe-doped CoP

Despite significant advancements in the detection of cadmium (Cd(II)) based on nanomaterial adsorbability, limited research has been conducted on ultra-sensitive and selective detection mechanisms, resulting in a lack of guidance for designing efficient interface materials to detect Cd(II). Herein, reductive Fe doping on CoP facilitates an efficient Fe-Co-P electron transfer path, which renders P the electron-rich site and subsequently splits a new orbital peak that matches with that of Cd(II) for excellent electrochemical performance. The sensitivity of Cd(II) was remarkably up to 109.75 μA μM-1 on the Fe-CoP modified electrode with excellent stability and repeatability, surpassing previously reported findings. Meanwhile, the electrode exhibits exceptional selectivity towards Cd(II) ions compared to some bivalent heavy metal ions (HMIs). Moreover, X-ray absorption fine structure (XAFS) analysis reveals the interaction between P and Cd(II), which is further verified via density functional theory (DFT) calculation with the new hybrid peaks resulting from the splitting peak of P atoms coupled with the orbital energy level of Cd(II). Generally, doping engineering for specific active sites and regulation of orbital electrons not only provides valuable insights for the subsequent regulation of electronic configuration but also lays the foundation for customizing highly sensitive and selectivity sensors.

Selective catalytic oxidation of formaldehyde on single V- and Cr-atom decorated magnetic C4N3 substrate: A first principles study

Formaldehyde (HCHO) is the most common indoor hazardous pollutant and has attracted great concern because its long-term exposure has adverse health effects on humans. Retention and catalytic oxidation of highly hazardous HCHO is an efficient and environmentally friendly method to use for air remediation, but a major obstacle to this procedure is the lack of an appropriate catalyst. Herein, two-dimensional magnetic C₄N₃ material with a 3d-transition metal as activate sites was systemically investigated in HCHO oxidation using density functional theory calculations. The results show that V-C₄N₃ and Cr-C₄N₃ have high structural stability and shallow activation barriers for O₂ decomposition; these characteristics provide the necessary precursors for the subsequent oxidation reaction. Moreover, the V-C₄N₃ and Cr-C₄N₃ catalysts have unique selective adsorption and catalysis toward HCHO in a mixture of some typical in-door volatile organic compounds (VOCs) and air. The corresponding dynamic barrier for each reaction step was investigated and the mechanism involved in HCHO oxidation was revealed in detail. Aggregation of metal atoms in the V-C₄N₃ and Cr-C₄N₃ catalysts is prevented by enormous diffusion resistance, and this is further confirmed by AIMD simulations. These results provide insightful guidance for developing advanced magnetic catalysts for HCHO oxidation to improve the remediation of air contaminants.