Yangyang Yang

Advanced oxidation processes (AOPs) based on persulfates such as peroxymonosulfate and peroxydisulfate via heterogeneous catalysts have been a research hotspot due to their outstanding performances in removing emerging organic contaminants (OCs). In this Review, we highlight the recent advances in theoretical simulations for persulfate-based AOPs (PS-AOPs) using density functional theory (DFT), with the emphasis on the catalyst properties and the mechanism of persulfate activation over a variety of heterogeneous catalysts (including nanocarbons, metals, and metal oxides). Moreover, the properties of OCs and their degradation mechanism by diverse reactive oxygen species investigated by theoretical computations are also summarized. The descriptors in computational studies and the related structure–performance relationships are discussed. Finally, the challenges and future research focuses of DFT simulations in PS-AOPs are proposed, including the evaluation of catalyst properties, elucidation of the persulfate activation mechanism, especially the nonradical pathway, and the rational design of on-demand catalysts.

Nature has developed striking light-powered proteins such as bacteriorhodopsin, which can convert light energy into conformational changes for biological functions. Such natural machines are a great source of inspiration for creation of their synthetic analogues. However, synthetic molecular machines typically operate at the nanometre scale or below. Translating controlled operation of individual molecular machines to a larger dimension, for example, to 10-100 nm, which features many practical applications, is highly important but remains challenging. Here we demonstrate a light-driven plasmonic nanosystem that can amplify the molecular motion of azobenzene through the host nanostructure and consequently translate it into reversible chiroptical function with large amplitude modulation. Light is exploited as both energy source and information probe. Our plasmonic nanosystem bears unique features of optical addressability, reversibility and modulability, which are crucial for developing all-optical molecular devices with desired functionalities.

Microplastics (MPs) are ubiquitous in the environment and are infiltrating the food chain, causing potential risks to living beings. However, current methods of MP removal from an aqueous environment are limited by low efficiency. Advanced oxidation processes (AOPs) are emerging techniques for MP purification. Herein, a hydrothermal coupled Fenton system is developed for decomposition of ultrahigh-molecular-weight polyethylene, achieving 95.9% weight loss in 16 h and 75.6% mineralization efficiency in 12 h. The high effectiveness is attributed to the synergy of hydrothermal hydrolysis, proton-rich environment, and massive production of hydroxyl radicals. The system is also efficient to remediate different petroleum-based plastics and maintains high efficiency in practical water bodies. Characterizations revealed a two-stage degradation process: chain unfolding/stretching and oxidation, giving rise to the formation of carbonyl groups and decreased crystallinity of MPs during the hydrothermal treatment. The chain stretching stage is pivotal to the whole treatment because it remarkably facilitates subsequent chain cleavage and Fenton oxidation. This study provides a new approach to removing MPs in water bodies and new insights into MP degradation by the AOP technology.