The electrochemical oxidation of a CO adlayer on Pt[n(111)×(111)] electrodes, with n = 30, 10, and 5, Pt(111), Pt(110) as well as a Pt(553) electrode (with steps of (100) orientation) in alkaline solution (0.1 M NaOH) has been studied using stripping voltammetry. On these electrodes, it is possible to distinguish CO oxidation at four different active oxidation sites on the surface, i.e. sites with (111), (110) and (100) orientation, and kink sites. The least active site for CO oxidation is the (111) terrace site. Steps sites are more active than the (111) terrace sites, the (110) site oxidizing CO at lower potential than the (100) site. The CO oxidation feature with the lowest overpotential (oxidation potential as low as 0.35 V vs. RHE) was ascribed to oxidation of CO at kink sites. The amount of CO oxidized at the active step or kink sites vs. the amount of CO oxidized at the (111) terrace sites depends on the concentration of the active sites and the time given for the terrace-bound CO to reach the active site. By performing CO stripping on the stepped surfaces at different scan rates, the role of CO surface diffusion is probed. The possible role of electronic effects in explaining the unusual activity and dynamics of CO adlayer oxidation in alkaline solution is discussed.

Microplastic pollution has become a global environmental concern with detrimental effects on ecosystems and human health. Effective removal of microplastics from water sources is crucial to mitigate their impacts. Advanced oxidative processes (AOPs) have emerged as promising strategies for the degradation and elimination of microplastics. This review provides a comprehensive overview of the application of AOPs in the removal of microplastics from water. Various AOPs, such as photocatalysis, ozonation, and Fenton-like processes, have shown significant potential for microplastic degradation. These processes generate highly reactive species, such as hydroxyl radicals, which can break down microplastics into smaller fragments or even mineralize them into harmless byproducts. The efficiency of photocatalytic oxidation depends on several factors, including the choice of photocatalysts, reaction conditions, and the physicochemical properties of microplastics. Furthermore, this review discusses the challenges associated with photocatalytic oxidation, such as the need for optimization of operating parameters and the potential formation of harmful byproducts. Overall, photocatalytic oxidation offers a promising avenue for the removal of microplastics from water, contributing to the preservation of aquatic ecosystems and safeguarding human health. However, further research is needed to address the limitations and optimize the implementation of this process for effective and sustainable microplastic remediation.