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Contact-electro-catalysis (CEC) is a green catalytic technology that reduces emissions and purifies the environment via contact electrification (CE) at the solid–liquid (S–L) interface to generate reactive oxygen species. However, CEC technology faces limitations under natural and industrial conditions and urgently needs to be developed to promote self-powered or low-cost chemical reactions using environmental energy. A low energy-conversion rate under complex natural or industrial conditions is the key limiting factor for large-scale applications. In this review, CEC under various natural and industrial conditions is discussed. First, the competitive relation between electron transfer and ion transfer in CE is proposed, wherein the CE mechanism details are compared to determine the effect on CEC. Additionally, strategies for promoting S–L electron transfer and controlling ion transfer are systematically analyzed using the condition factors of the solid catalyst, water phase, and external environment, such as functional groups, ions in the liquid, and temperature. Finally, the challenges associated with CEC technology in engineering implementation are summarized. This review aims to provide insight into the competitive relation between electron and ion transfer in S–L CE for CEC and provides new ideas for the engineering of CEC technology under complex natural and industrial conditions. [ABSTRACT FROM AUTHOR]

Nanozymes are next-generation of nanomaterials with enzyme-like activities. In particular, nanozymes with peroxidase (POD)-like activity have been utilized in various fields, including antibacterial, detection, degradation, etc. However, their extensive applications were limited by their low catalytic activity currently. Herein, we have presented a composite nanozyme based on attapulgite (ATP) (Fe-ATP-MoS2 (FAM)), which exhibited enhanced POD-like activity (185.33 U·mg−1), 4.25 times higher than that of Fe-MoS2 (FM) (43.63 U·mg−1). The density functional theory (DFT) calculations indicated that the addition of ATP increased the electron density of metal centers (Mo and Fe). More importantly, Michaelis–Menten kinetics revealed that the introduction of ATP significantly enhanced the binding affinities of substrates through the pores of ATP, forming a highly concentrated substrate microenvironment and thus promoting its POD-like activity. Additionally, from molecular size and kinetic analysis, we proposed that the changes in substrate size before and after oxidation also significantly affected its Michaelis-constant (Km) value. Furthermore, we utilized FAM in the applications of highly effective antibacterial application and sensitive detection of glutathione (GSH). In conclusion, this work provides a novel approach for designing a highly efficient nanozyme based on natural mineral composites. [ABSTRACT FROM AUTHOR]

Significant progress has been made in using triboelectric nanogenerators (TENGs) to harvest sustainable energy from wind, waves, human activities, and water droplets. Natural materials, which are non-synthetic and have the advantages of being low-cost, environmentally friendly, biodegradable, and partially biocompatible, can be used to prepare green TENGs. In this review, the latest advances made in natural-materials-based TENGs are summarized. The triboelectric mechanisms and properties of natural-materials-based TENGs derived from animals, plants, humans, microorganisms, and minerals are discussed. The output performance, features, and applications of the natural materials used to construct the tribopositive and tribonegative layers of TENGs are discussed. Moreover, the triboelectric sequence of the natural materials is summarized to compare their ability to gain or lose charge in the process of friction. Finally, the challenges facing natural-materials-based TENGs, such as complex processing, short service life, lack of stability, few tribonegative materials, and low power density, are listed. It is thus anticipated that this review will encourage the use of natural materials to manufacture eco-friendly TENGs that have broad application prospects in the field of energy conversion. [ABSTRACT FROM AUTHOR]

Fiber composite materials with filler–matrix friction between fibers can produce triboelectric signals realizing endogenous triboelectric nanogenerators (TENGs). Endogenous TENGs are easy to package and do not require controlled distance as piezoelectric nanogenerators (PENGs) do, but without piezoelectric materials. However, limited studies have been conducted on the design and control of the filler content and distribution in fibers to improve the electricity generation of endogenous TENGs, which is significant for the evolution as a replacement for PENGs. In this study, an endogenous TENG was prepared using a polylactic acid (PLA) composite fiber film and MXene as the matrix and filler, respectively. The generated open-circuit voltage, short-circuit current, and charge increase when PLA–MXene contacts are introduced between the fibers, reaching the highest values of 16 V, 1.2 μA, and 7 nC, respectively, in the case of 1 wt% MXene/PLA (1 wt% PMX). Then, a blend film (B-M film) was designed to optimize the MXene distribution to further increase the number of PLA–MXene contacts and the B-M film with 1 wt% MXene shows a higher output power of 4.55 μW cm−2 than that with 1 wt% PMX (1.23 μW cm−2). This study reveals the effects of the filler content and distribution on the electricity generation of endogenous TENGs based on composite fiber films, and the employed blending strategy provides a new idea for improving their output performance. [ABSTRACT FROM AUTHOR]