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In this work, an S-doped biochar-supported CuInS2 quantum dot-sensitized Bi2MoO6 hierarchical flower (CIS@BMO@SL) was prepared using a bottom-up technique. The partial thermal reduction of CuInS2 quantum dot-sensitized Bi2MoO6 successfully fabricated a dual heterojunction, which is composed of CuInS2/Bi2MoO6 Z-scheme and Bi/Bi2MoO6 Mott–Schottky heterojunctions. The dual heterojunction was identified by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy. Under the synergistic effect of the dual heterojunction, the electronic kinetics was significantly improved. Furthermore, the charge transfer resistance was further reduced by S-doped biochar. Under visible light irradiation, an exceptional xylonic acid yield of 86.59% was realized by CIS@BMO@SL. In this photocatalytic system, all active oxidation species, namely, ·OH, 1O2, ·O2 –, and h+, were beneficial for producing xylonic acid. The primary role of h+ in the photocatalytic system was demonstrated via a poisoning experiment. According to XPS, the poisoning experiment, and electron spin resonance, the generation of ·O2 – reveals a Z-scheme heterojunction between CuInS2 and Bi2MoO6.

The hydrogen bond network (HBN) is of primary importance to the proton transport in Nafion. However, the evolution of the HBN in Nafion with water content and the underlying thermodynamics have not been revealed. In this study, the free energy of hydrogen bond formation is calculated based on an information-theoretic approach, indicating the formation of HBN in Nafion is a thermodynamically favorable process as the water content increases. In addition, the evolution of HBN in Nafion with water content including the topology and basic building blocks has been visualized and quantified by a ring statistics approach based on graph theory. Finally, the rearrangement dynamics and heterogeneity of HBN are also disclosed. This study provides a fundamental and comprehensive understanding of HBN in Nafion including the formation thermodynamics, topology, and rearrangement dynamics, which is useful for the design of high-performance proton exchange membranes.

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Grinding, an essential procedure before flotation, to some extent, determines the flotation behavior of minerals. In this study, the effect of grinding media on the flotation behavior of fluorite using sodium oleate (NaOl) as a collector was investigated via micro-flotation experiments, zeta potential measurements, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that, compared with the fluorite particles ground by ceramic media, the ones ground by cast iron media adsorbed less NaOl, resulting in lower flotation recovery. The lower flotation recovery of fluorite particles ground by cast iron media resulted from the coating of the hydrophilic Fe precipitates generated in the grinding, including Fe(0), Fe(OH)2, and Fe(OH)3 on their surfaces. These Fe precipitates may cover the Ca active sites and increase the hydration membrane which can inhibit the further NaOl adsorption. This research reveals the effect of grinding media on the flotation behavior of fluorite and guides for media selection in disposing of fluorite ore.