Over the past few decades, researchers have established artificial enzymes as highly stable and low-cost alternatives to natural enzymes in a wide range of applications. A variety of materials including cyclodextrins, metal complexes, porphyrins, polymers, dendrimers and biomolecules have been extensively explored to mimic the structures and functions of naturally occurring enzymes. Recently, some nanomaterials have been found to exhibit unexpected enzyme-like activities, and great advances have been made in this area due to the tremendous progress in nano-research and the unique characteristics of nanomaterials. To highlight the progress in the field of nanomaterial-based artificial enzymes (nanozymes), this review discusses various nanomaterials that have been explored to mimic different kinds of enzymes. We cover their kinetics, mechanisms and applications in numerous fields, from biosensing and immunoassays, to stem cell growth and pollutant removal. We also summarize several approaches to tune the activities of nanozymes. Finally, we make comparisons between nanozymes and other catalytic materials (other artificial enzymes, natural enzymes, organic catalysts and nanomaterial-based catalysts) and address the current challenges and future directions (302 references).

Nanomaterials with enzyme-like characteristics (nanozymes): next-generation artificial enzymes

Carbon nanodots (C-dots) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching. In this review, by introducing the synthesis and photo- and electron-properties of C-dots, we hope to provide further insight into their controversial emission origin (particularly the upconverted photoluminescence) and to stimulate further research into their potential applications, especially in photocatalysis, energy conversion, optoelectronics, and sensing.

Carbon nanodots: synthesis, properties and applications

Carbon quantum dots (CQDs, C-dots or CDs), which are generally small carbon nanoparticles (less than 10 nm in size) with various unique properties, have found wide use in more and more fields during the last few years. In this feature article, we describe the recent progress in the field of CQDs, focusing on their synthetic methods, size control, modification strategies, photoelectric properties, luminescent mechanism, and applications in biomedicine, optronics, catalysis and sensor issues.

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Carbon quantum dots: synthesis, properties and applications

and Applications of Fullerenes, Carbon Dots, Nanotubes, Graphene, Nanodiamonds, and Combined Superstructures Vasilios Georgakilas,† Jason A. Perman,‡ Jiri Tucek,‡ and Radek Zboril*,‡ †Material Science Department, University of Patras, 26504 Rio Patras, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University in Olomouc, 17 listopadu 1192/12, 771 46 Olomouc, Czech Republic

Broad family of carbon nanoallotropes: classification, chemistry, and applications of fullerenes, carbon dots, nanotubes, graphene, nanodiamonds, and combined superstructures.

ConspectusNatural enzymes, exquisite biocatalysts mediating every biological process in living organisms, are able to accelerate the rate of chemical reactions up to 1019 times for specific substrates and reactions. However, the practical application of enzymes is often hampered by their intrinsic drawbacks, such as low operational stability, sensitivity of catalytic activity to environmental conditions, and high costs in preparation and purification. Therefore, the discovery and development of artificial enzymes is highly desired. Recently, the merging of nanotechnology with biology has ignited extensive research efforts for designing functional nanomaterials that exhibit various properties intrinsic to enzymes. As a promising candidate for artificial enzymes, catalytically active nanomaterials (nanozymes) show several advantages over natural enzymes, such as controlled synthesis in low cost, tunability in catalytic activities, as well as high stability against stringent conditions.In this Account, we fo...

Catalytically Active Nanomaterials: A Promising Candidate for Artificial Enzymes

https://www.rsc.org/suppdata/cc/c1/c1cc11943e/c1cc11943e.pdf

Carbon nanodots as peroxidase mimetics and their applications to glucose detection

Comparative study on COD removal from reverse osmosis concentrate using two physicochemical combined processes

Cavitation effect is the most common phenomenon in the process of jet. In this work, the method of CFD numerical simulation is used to study the cavitation behaviour in the process of single hole jet. In order to obtain the mixing situation and change process of gaseous water and liquid water produced in the nozzle, the Euler multiphase flow model and the realizable k-epsilon model in the turbulence model are used. The simulation results show that the degree and frequency of liquid column breakage of cavitation water jet are far higher than those of ordinary water jet. And the structure of the nozzle also has the most ideal situation. When the nozzle inlet size is 20 mm, the nozzle diameter is 1 mm, and the nozzle length is 5 mm, which is most conducive to the growth and diffusion of cavitation bubbles. The cavitation effect increases with the increase of the inlet jet velocity, but the promotion effect does not increase significantly when the inlet velocity is greater than 2.5 m/s. From the perspective of energy consumption, the optimum velocity at this time is 2.5 m/s. And the pressure environment at the nozzle outlet also affects the cavitation phenomenon, mainly as follows: positive pressure can inhibit the cavitation effect, negative pressure can promote the cavitation effect, but the negative pressure has a limited effect on the degree of cavitation.

Zhiliang Cheng

Papers

Carbon nanodots as peroxidase mimetics and their applications to glucose detection

Comparative study on COD removal from reverse osmosis concentrate using two physicochemical combined processes

CFD Simulation of the Cavitation Behaviour in Single Jet Process via Outlet Pressure