Recent advances on metal-free graphene-based catalysts for the production of industrial chemicals

Theoretical Investigation of the BCN Monolayer and Their Derivatives for Metal-free CO2 Photocatalysis, Capture, and Utilization

In recent years, carbon capture and utilization (CCU) has been explored as an attractive solution to global warming, which is mainly caused by increasing CO2 emission levels. Many functional materials have been developed for removing atmospheric CO2 and converting it to more useful forms of carbon. Traditional metallic photocatalytic species have drawbacks-photocorrosion, low visible-light absorbance, and environmental damage; therefore, metal-free materials have attracted considerable research attention. In particular, boron nitride (BN) possesses unique B-N bonds, characterized by a large difference in the electronegativity of atoms that facilitates CO2 reduction, and catalytic CO2 reduction by boron carbon nitride (BCN) has been demonstrated under visible light; hence, these two materials can be considered potential CO2 reduction photocatalysts. However, further modification of the materials and their applicability to other CCU applications have not been extensively explored. Therefore, we decided to investigate the modification of BCN monolayers, with the aim of ensuring that the properties of the materials are better suited, first, to the requirements of CO2 photocatalysis, and second, to those of carbon capture or other optoelectronic applications. In this study, we considered various novel BCN monolayers, based on modification via metal-free substitutional doping and nitrogen vacancy creation, and performed first-principles density functional theory calculations. The effects of the modifications on band gap tuning, charge transfer, and the CO2 adsorption ability were all studied. Specifically, ON-B13C8N11 and SiC-2 × 2-BC6N were shown to possess excellent properties for photocatalytic CO2 reduction, and OC-2 × 2-BC6N and Nv-4 × 4-BN can be considered for future CO2 capture materials. These results contribute to existing CCU approaches, suggesting that BCN monolayer modification merits further investigation, and offering insights relevant to other photocatalytic applications.

Critical Review on the Mechanisms of Fe2+ Regeneration in the Electro-Fenton Process: Fundamentals and Boosting Strategies

This review presents an exhaustive overview on the mechanisms of Fe³⁺ cathodic reduction within the context of the electro-Fenton (EF) process. Different strategies developed to improve the reduction rate are discussed, dividing them into two categories that regard the mechanistic feature that is promoted: electron transfer control and mass transport control. Boosting the Fe³⁺ conversion to Fe²⁺ via electron transfer control includes: (i) the formation of a series of active sites in both carbon- and metal-based materials and (ii) the use of other emerging strategies such as single-atom catalysis or confinement effects. Concerning the enhancement of Fe²⁺ regeneration by mass transport control, the main routes involve the application of magnetic fields, pulse electrolysis, interfacial Joule heating effects, and photoirradiation. Finally, challenges are singled out, and future prospects are described. This review aims to clarify the Fe³⁺/Fe²⁺ cycling process in the EF process, eventually providing essential ideas for smart design of highly effective systems for wastewater treatment and valorization at an industrial scale.

Two-Dimensional Material-Based Biosensors for Virus Detection

Viral infections are one of the major causes of mortality and economic losses worldwide. Consequently, efficient virus detection methods are crucial to determine the infection prevalence. However, most detection methods face challenges related to false-negative or false-positive results, long response times, high costs, and/or the need for specialized equipment and staff. Such issues can be overcome by access to low-cost and fast response point-of-care detection systems, and two-dimensional materials (2DMs) can play a critical role in this regard. Indeed, the unique and tunable physicochemical properties of 2DMs provide many advantages for developing biosensors for viral infections with high sensitivity and selectivity. Fast, accurate, and reliable detection, even at early infection stages by the virus, can be potentially enabled by highly accessible surface interactions between the 2DMs and the analytes. High selectivity can be obtained by functionalization of the 2DMs with antibodies, nucleic acids, proteins, peptides, or aptamers, allowing for specific binding to a particular virus, viral fingerprints, or proteins released by the host organism. Multiplexed detection and discrimination between different virus strains are also feasible. In this Review, we present a comprehensive overview of the major advances of 2DM-based biosensors for the detection of viruses. We describe the main factors governing the efficient interactions between viruses and 2DMs, making them ideal candidates for the detection of viral infections. We also critically detail their advantages and drawbacks, providing insights for the development of future biosensors for virus detection. Lastly, we provide suggestions to stimulate research in the fast expanding field of 2DMs that could help in designing advanced systems for preventing virus-related pandemics.

Graphene-Oxide-Based Electrochemical Sensors for the Sensitive Detection of Pharmaceutical Drug Naproxen

Here we report on a selective and sensitive graphene-oxide-based electrochemical sensor for the detection of naproxen. The effects of doping and oxygen content of various graphene oxide (GO)-based nanomaterials on their respective electrochemical behaviors were investigated and rationalized. The synthesized GO and GO-based nanomaterials were characterized using a field-emission scanning electron microscope, while the associated amounts of the dopant heteroatoms and oxygen were quantified using x-ray photoelectron spectroscopy. The electrochemical behaviors of the GO, fluorine-doped graphene oxide (F-GO), boron-doped partially reduced graphene oxide (B-rGO), nitrogen-doped partially reduced graphene oxide (N-rGO), and thermally reduced graphene oxide (TrGO) were studied and compared via cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that GO exhibited the highest signal for the electrochemical detection of naproxen when compared with the other GO-based nanomaterials explored in the present study. This was primarily due to the presence of the additional oxygen content in the GO, which facilitated the catalytic oxidation of naproxen. The GO-based electrochemical sensor exhibited a wide linear range (10 µM–1 mM), a high sensitivity (0.60 µAµM⁻¹cm⁻²), high selectivity and a strong anti-interference capacity over potential interfering species that may exist in a biological system for the detection of naproxen. In addition, the proposed GO-based electrochemical sensor was tested using actual pharmaceutical naproxen tablets without pretreatments, further demonstrating excellent sensitivity and selectivity. Moreover, this study provided insights into the participatory catalytic roles of the oxygen functional groups of the GO-based nanomaterials toward the electrochemical oxidation and sensing of naproxen.

Gas–solid acetylene dimerization over copper-based catalysts

A gas–solid acetylene dimerization over copper-based catalysts, with high acetylene conversion and MVA selectivity and convenient operation, was reported.