Machine learning (ML) methods were applied to predict the capacitance of carbon-based supercapacitors.

As sustainable and advanced nanomaterials, cellulose nanocrystals (CNCs) attract extensive attention from both academia and industry due to their superior physical and chemical properties. Strong inorganic acid (e.g., H₂SO₄) hydrolysis is the most common method for the preparation of CNCs because of its high efficiency. However, inorganic acid hydrolysis faces several limitations such as severe equipment corrosion, over-degradation of cellulose, pollution of the environment, and the use of a large amount of water. This review comprehensively summarizes sustainable strategies invented in recent years for the preparation of CNCs, including the oxidation method, ionic liquid treatment, deep eutectic solvent treatment, enzymatic hydrolysis, inorganic solid acid hydrolysis, organic acid hydrolysis, supercritical water hydrolysis, HCl vapor/gas hydrolysis, and the electron beam radiation method. It is believed that CNCs, as green and renewable nanomaterials, have broad application prospects in the future, and the realization of the green, low-cost, and sustainable preparation of CNCs will be the prerequisite guarantee for the large-scale application of CNCs.

Nanoporous silica is used in a wide variety of applications, ranging from bioanalytical tools and materials for energy storage and conversion as well as separation devices. The surface charge density of nanopores is not easily measured by experiment yet plays a vital role in the performance and functioning of silica nanopores. Herein, we report a theoretical model to describe charge regulation in silica nanopores by combining the surface-reaction model and the classical density functional theory (CDFT). The theoretical predictions provide quantitative insights into the effects of pH, electrolyte concentration, and pore size on the surface charge density and electric double layer structure. With a fixed pore size, the surface charge density increases with both pH and the bulk salt concentration similar to that for an open surface. At fixed pH and salt concentration, the surface charge density rises with the pore size until it reaches the bulk asymptotic value when the surface interactions become negligible. At high pH, the surface charge density is mainly determined by the ratio of the Debye screening length to the pore size (λ_D/D).