Adsorption and desorption mechanisms on graphene oxide nanosheets: Kinetics and tuning

Abstract

A knowledge of the adsorption and desorption behavior of sorbates on surface adsorptive site (SAS) is the key to optimizing the chemical reactivity of catalysts. However, direct identification of the chemical reactivity of SASs is still a challenge due to the limitations of characterization techniques. Here, we present a new pathway to determine the kinetics of adsorption/desorption on SASs of graphene oxide (GO) based on total internal reflectance fluorescence microscopy. The switching on and off of the fluorescent signal of SAS lit by carbon dots (CDs) was used to trace the adsorption process and desorption process. We find that sodium pyrophosphate (PPi) could increase the adsorption equilibrium of CDs thermodynamically and promote the substrate-assisted desorption pathway kinetically. At the single turnover level, it was disclosed that the species that can promote desorption may also be an adsorption promoter. Such discovery provides significant guidance for improving the chemical reactivity of the heterogeneous catalyst.

Pt‐WOx/C Catalysts for α, β‐Unsaturated Aldehydes Hydrogenation: An NMR Study of the Effect of the Reactant Adsorption on Activity and Selectivity

“…On the contrary, values lower than 0.9 indicates that there is an interaction, which is stronger the more the value decreases. [20] As the catalytic activity is strongly affected by the adsorption/desorption equilibrium of reactants and products on the catalyst surface, [32] the determination of the interaction between the substrate with the catalytic surface in the real reaction medium is crucial. 13 C NMR could provide useful data that could be correlated with the catalytic activity.…”

Multimodal Contrast Agents for Optoacoustic Brain Imaging in Small Animals

“…The majority of preclinical OA molecular imaging in the brain has been focused on detecting the pathological changes in a glioblastoma model, and applications have also emerged in animal models of stroke, epilepsy, Alzheimer's disease (AD), and neuroinflammation (Ni et al, 2017;Xi et al, 2017;Ni et al, 2018a;Ni et al, 2018b;Ishikawa et al, 2018;Ni et al, 2020a;Kasten et al, 2020;Razansky et al, 2021). Different types of exogenous contrast agents have been developed, including synthetic (chemical dyes or nanoparticles (NPs)), semi-genetic, and genetic contrast agents (e.g., genetically encoded calcium indicators and reversibly switchable OA proteins (Roberts et al, 2018;Qian et al, 2019;Mishra et al, 2020;Farhadi et al, 2021;Qu et al, 2021;Shemetov et al, 2021)). The criteria for contrast agent applied in OA brain imaging include a suitable absorbance spectrum (>600 nm wavelength) to allow unmixing with endogenous signals (e.g., Hb/HbO and melanin) and sufficient brain penetration depth, high affinity and specific binding to the target, sufficient blood-brain barrier entrance, photostability, solubility, low toxicity, high thermodynamics for MRI probes, and optimal pharmacokinetics (Weber et al, 2016 (Pu et al, 2014;Li and Chen, 2015;Weber et al, 2016;Yang et al, 2018;Yu et al, 2019;Zhan et al, 2019;Xu et al, 2020;Cheng et al, 2021;Fan et al, 2021;Joseph et al, 2021;Qi et al, 2021a;Tuo et al, 2021;Wang et al, 2021a;Wang et al, 2021b;Zhen et al, 2021).…”

More Than Energy Harvesting in Electret Electronics‐Moving toward Next‐Generation Functional System

“…The mechanical energy from nature can be used to power small electronic devices from around the environment. [ 10–44 ] With the aid of intelligent wearable electronics for functional purposes, energy harvesters converting ambient mechanical energy into electricity have attracted great attention. Commonly, several promising methods can be used to provide energy to run electronic devices, such as electrets by motion, electrostatic from vibration, and electromagnetic with relative speed, while triboelectric energy harvesting with friction can be adopted for healthcare, human–machine interaction, wireless transmission, and self‐charging units for electronics.…”