A Rising 2D Star: Novel MBenes with Excellent Performance in Energy Conversion and Storage

As a flourishing member of the two-dimensional (2D) nanomaterial family, MXenes have shown great potential in various research areas. In recent years, the continued growth of interest in MXene derivatives, 2D transition metal borides (MBenes), has contributed to the emergence of this 2D material as a latecomer. Due to the excellent electrical conductivity, mechanical properties and electrical properties, thus MBenes attract more researchers' interest. Extensive experimental and theoretical studies have shown that they have exciting energy conversion and electrochemical storage potential. However, a comprehensive and systematic review of MBenes applications has not been available so far. For this reason, we present a comprehensive summary of recent advances in MBenes research. We started by summarizing the latest fabrication routes and excellent properties of MBenes. The focus will then turn to their exciting potential for energy storage and conversion. Finally, a brief summary of the challenges and opportunities for MBenes in future practical applications is presented.

Electrochemical reduction of NO catalyzed by boron-doped C60 fullerene: a first-principles study

The electrochemical reduction of nitrogen monoxide (NO) is one of the most promising approaches for converting this harmful gas into useful chemicals. Using density functional theory calculations, the work examines the potential of a single B atom doped C60 fullerene (C59B) for catalytic reduction of NO molecules. The results demonstrate that the NO may be strongly activated over the B atom of C59B, and that the subsequent reduction process can result in the formation of NH3 and N2O molecules at low and high coverages, respectively. Based on the Gibbs free energy diagram, it is inferred that the C59B has excellent catalytic activity for NO reduction at ambient conditions with no potential-limiting. At normal temperature, the efficient interaction between the *NOH and NO species might lead to the spontaneous formation of the N2O molecule. Thus, the findings of this study provide new insights into NO electrochemical reduction on heteroatom doped fullerenes, as well as a unique strategy for fabricating low-cost NO reduction electrocatalysts with high efficiency.

CO2 Capture, Separation and Reduction on Boron-Doped MoS2 , MoSe2 and Heterostructures with Different Doping Densities: A Theoretical Study

Designing high-performance materials for CO₂ capture and conversion is of great significance to reduce the greenhouse effect and alleviate the energy crisis. The strategy of doping is widely used to improve activity and selectivity of the materials. However, it is unclear how the doping densities influence the materials' properties. Herein, we investigated the mechanism of CO₂ capture, separation and conversion on MoS₂ , MoSe₂ and Janus MoSSe monolayers with different boron doping levels using density functional theory (DFT) simulations. The results indicate that CO₂ , H₂ and CH₄ bind weakly to the monolayers without and with single-atom boron doping, rendering these materials unsuitable for CO₂ capture from gas mixtures. In contrast, CO₂ binds strongly to monolayers doped with diatomic boron, whereas H₂ and CH₄ can only form weak interactions with these surfaces. Thus, the monolayers doped with diatomic boron can efficiently capture and separate CO₂ from such gas mixtures. The electronic structure analysis demonstrates that monolayers doped with diatomic doped are more prone to donating electrons to CO₂ than those with single-atom boron doped, leading to activation of CO₂ . The results further indicate that CO₂ can be converted to CH₄ on diatomic boron doped catalysts, and MoSSe is the most efficient of the surfaces studied for CO₂ capture, separation and conversion. In summary, the study provides evidence for the doping density is vital to design materials with particular functions.

Activation of the methane C–H bond by Al- and Ga-doped graphenes: a DFT investigation

The potential of Al- and Ge-embedded graphene to activate the C–H bond of CH4 in the presence of a N2O molecule was studied using DFT calculations.

Nitric oxide reduction by microbial fuel cell with carbon based gas diffusion cathode for power generation and gas purification

Nitric oxide (NO) from anthropogenic emission is one of the main air contaminants and induces many environmental problems. Microbial fuel cells (MFCs) with gas diffusion cathode provide an alternative technology for NO reduction. In this work, pure NO as the sole electron acceptor of MFCs with gas diffusion cathode (NO-MFCs) was verified. The NO-MFCs obtained a maximum power density of 489 ± 50 mW/m². Compared with MFCs using O₂ in air as electron acceptor (Air-MFCs), the columbic efficiency increased from 23.2% ± 4.3% (Air-MFCs) to 55.7% ± 4.6% (NO-MFCs). The NO removal rate was 12.33 ± 0.14 mg/L/h and N₂ was the main reduction product. Cathode reduction was the dominant pathway of NO conversion in NO-MFCs, including abiotic electrochemical reduction and microbial denitrification process. The predominant genera in anodic microbial community changed from exoelectrogenic bacteria in Air-MFCs to denitrifying bacteria in NO-MFCs and effected the power generation.

Insights into the promotion role of phosphorus doping on carbon as a metal-free catalyst for low-temperature selective catalytic reduction of NO with NH3

The catalytic reduction of NO with NH₃ (NH₃-SCR) on phosphorus-doped carbon aerogels (P-CAs) was studied in the temperature range of 100–200 °C. The P-CAs were prepared by a one-pot sol–gel method by using phosphoric acid as a phosphorus source followed by carbonization at 600–900 °C. A correlation between catalytic activity and surface P content is observed. The P-CA-800_vac sample obtained via carbonization at 800 °C and vacuum treatment at 380 °C shows the highest NO conversion of 45.6–76.8% at 100–200 °C under a gas hourly space velocity of 500 h⁻¹ for the inlet gas mixture of 500 ppm NO, 500 ppm NH₃ and 5.0 vol% O₂. The coexistence of NH₃ and O₂ is essential for the high conversion of NO on the P-CA carbon catalysts, which can decrease the spillover of NO₂ and N₂O. The main Brønsted acid sites derived from P-doping and contributed by the C–OH group at edges of carbon sheets are beneficial for NH₃ adsorption. In addition, the C₃–P Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O configuration seems to have the most active sites for favorable adsorption and dissociation of O₂ and facilitates the formation of NO₂. Therefore, the simultaneous presence of acidic groups for NH₃ adsorption and the C₃–PO active sites for NO₂ generation due to the activation of O₂ molecules is likely responsible for the significant increase in the NH₃-SCR activity over the P–CAs. The transformation of C₃–PO to C–O–P functional groups after the reaction is found, which could be assigned to the oxidation of C₃–PO by the dissociated O*, resulting in an apparent decrease of catalytic activity for P-CAs. The C–O–P based functional groups are also active in the NH₃-SCR reaction.

P species can effectively enhance the catalytic activity of carbon aerogels for NO reduction at low temperature.