A metal-free photoactive nitrogen-doped carbon nanosolenoid with broad absorption in visible region for efficient photocatalysis

All-in-one photothermal/catalytic flexible membrane for highly efficient desalination and organic pollutant degradation

Interfacial solar vapor generation (ISVG) accompanied by photocatalytic degradation holds immense potential to mitigate water scarcity and pollution. Distinct from the two detached functional components (photothermal agent and photocatalyst) in a conventional evaporator, in this study, an all-in-one photothermal/catalytic agent, nitrogen-containing honeycomb carbon nanosheets (NHC), was engineered for synergistic high-efficiency steam generation and photocatalysis functions. It was demonstrated that the superoxide radical generated on the surface of NHC conferred its catalytic activity to the photodegradation of organic pollutants under full solar spectrum irradiation. A proof-of-concept multifunctional evaporator (called NHC@PEI/MCE), consisting of NHC grafted with polyethyleneimine (PEI) and a hydrophilic mixed cellulose ester membrane (MCE), was fabricated to achieve both solar-driven desalination and organic pollutant degradation. Owing to its excellent light absorption capability (∼96%), reduced evaporation enthalpy (1358 J g-1) and minimized heat loss (8.8%), the bi-layered evaporator performed a rapid water evaporation rate of 1.66 kg m-2 h-1 under one standard sun illumination. Notably, the edge-preferential crystallization strategy enabled the bi-layered evaporator to maintain long-term stability for continuous water evaporation and salt harvesting over 80 h in a concentrated 3.5 wt% NaCl solution. The design of the all-in-one photothermal/catalytic agent NHC ensured the synchronous removal of organic pollutants. The removal rates of methylene blue and phenol were 99.82% and 79.6%, respectively. Additionally, the reduction rate of total organic carbon (TOC) in the actual coking wastewater was found to be 96.6%. The exceptional purification capabilities across diverse water systems surpassed those of membrane materials lacking NHC. The exploration of the multifunctional evaporator offers a novel approach to achieving high-efficiency utilization of solar energy for the conversion of both seawater and industrial wastewater into freshwater.

General In Situ Engineering of Carbon-Based Materials on Carbon Fiber for In Vivo Neurochemical Sensing

Developing real-time, dynamic, and in situ analytical methods with high spatial and temporal resolutions is crucial for exploring biochemical processes in the brain. Although in vivo electrochemical methods based on carbon fiber (CF) microelectrodes are effective in monitoring neurochemical dynamics during physiological and pathological processes, complex post modification hinders large-scale productions and widespread neuroscience applications. Herein, we develop a general strategy for the in situ engineering of carbon-based materials to mass-produce functional CFs by introducing polydopamine to anchor zeolitic imidazolate frameworks as precursors, followed by one-step pyrolysis. This strategy demonstrates exceptional universality and design flexibility, overcoming complex post-modification procedures and avoiding the delamination of the modification layer. This simplifies the fabrication and integration of functional CF-based microelectrodes. Moreover, we design highly stable and selective H+, O2, and ascorbate microsensors and monitor the influence of CO2 exposure on the O2 content of the cerebral tissue during physiological and ischemia-reperfusion pathological processes.

Vacancy Engineering in 2D Transition Metal Chalcogenide Photocatalyst: Structure Modulation, Function and Synergy Application

Transition metal chalcogenides (TMCs) are widely used in photocatalytic fields such as hydrogen evolution, nitrogen fixation, and pollutant degradation due to their suitable bandgaps, tunable electronic and optical properties, and strong reducing ability. The unique 2D malleability structure provides a pre-designed platform for customizable structures. The introduction of vacancy engineering makes up for the shortcomings of photocorrosion and limited light response and provides the greatest support for TMCs in terms of kinetics and thermodynamics in photocatalysis. This work reviews the effect of vacancy engineering on photocatalytic performance based on 2D semiconductor TMCs. The characteristics of vacancy introduction strategies are summarized, and the development of photocatalysis of vacancy engineering TMCs materials in energy conversion, degradation, and biological applications is reviewed. The contribution of vacancies in the optical range and charge transfer kinetics is also discussed from the perspective of structure manipulation. Vacancy engineering not only controls and optimizes the structure of the TMCs, but also improves the optical properties, charge transfer, and surface properties. The synergies between TMCs vacancy engineering and atomic doping, other vacancies, and heterojunction composite techniques are discussed in detail, followed by a summary of current trends and potential for expansion.

Spatial engineering of single-atom Fe adjacent to Cu-assisted nanozymes for biomimetic O2 activation

The precise design of single-atom nanozymes (SAzymes) and understanding of their biocatalytic mechanisms hold great promise for developing ideal bio-enzyme substitutes. While considerable efforts have been directed towards mimicking partial bio-inspired structures, the integration of heterogeneous SAzymes configurations and homogeneous enzyme-like mechanism remains an enormous challenge. Here, we show a spatial engineering strategy to fabricate dual-sites SAzymes with atomic Fe active center and adjacent Cu sites. Compared to planar Fe-Cu dual-atomic sites, vertically stacked Fe-Cu geometry in FePc@2D-Cu-N-C possesses highly optimized scaffolds, favorable substrate affinity, and fast electron transfer. These characteristics of FePc@2D-Cu-N-C SAzyme induces biomimetic O2 activation through homogenous enzymatic pathway, resembling functional and mechanistic similarity to natural cytochrome c oxidase. Furthermore, it presents an appealing alternative of cytochrome P450 3A4 for drug metabolism and drug-drug interaction. These findings are expected to deepen the fundamental understanding of atomic-level design in next-generation bio-inspired nanozymes.