Mechanistic study of the competition between carbon dioxide reduction and hydrogen evolution reaction and selectivity tuning via loading single-atom catalysts on graphitic carbon nitride

In the context of catalytic CO2 reduction (CO2RR), the interference of the inherent hydrogen evolution reaction (HER) and the possible selectivity towards CO have posed a significant challenge to the generation of formic acid. To address this hurdle, in this work, we have investigated the impact of different single-atom metal catalysts on tuning selectivity by employing density functional theory (DFT) calculations to scrutinize the reaction pathways. Single-atom catalysts supported on carbon-based systems have proven to be pivotal in altering both the activity and selectivity of the CO2RR. In this study, a series of single-atom-metal-loaded g-C3N4 monolayers (MCN, M = Ni, Cu, Zn, Ga, Cd, In, Sn, Pb, Ag, Au, Bi, Pd and Pt) were systematically examined. Through detailed DFT calculations, we explored their influence on reaction selectivity between the *COOH and *OCHO intermediates. Notably, NiCN favors the reaction via the *OCHO route, with a significantly lower rate-determining potential of 0.36 eV, which is approximately 73.5% lower than that of the CN system (1.36 eV). Most importantly, the Ni single-atom catalyst with lower coordination significantly enhances CO2 adsorption, promoting CO2RR over HER. Overall, this study, guided by DFT calculations, provides a theoretical prediction of how the selection of single-atom metal catalysts can effectively modulate the reaction pathway, thereby offering a potential solution for achieving high product selectivity in CO2RR.

Enhanced Photo-Assisted Fenton Degradation of Antibiotics over Iron-Doped Bi-Rich Bismuth Oxybromide Photocatalyst

Herein, combining photocatalysis and Fenton oxidation, a photo-assisted Fenton system was conducted using Fe-doped Bi₄O₅Br₂ as a highly efficient photocatalyst to realize the complete degradation of Tetracycline antibiotics under visible light. It has been observed that the optimized photocatalyst 5%Fe-doped Bi₄O₅Br₂ exhibits a degradation efficiency of 100% for Tetracycline with H₂O₂ after 3 h visible-light irradiation, while a degradation percentage of 59.8% over the same photocatalyst and 46.6% over pure Bi₄O₅Br₂ were obtained without the addition of H₂O₂ (non-Fenton process). It is unambiguous that a boost photo-assisted Fenton system for the degradation of Tetracycline has been established. Based on structural analysis, it demonstrated that the Fe atoms in place of the Bi sites may result in the distortion of the local structure, which induced the occurrence of the spontaneous polarization and thus enhanced the built-in electric field. The charge separation efficiency is enhanced, and the recombination of electrons and holes is inhabited so that more charges are generated to reach the surface of the photocatalyst and therefore improve the photocatalytic degradation efficiency. Moreover, more Fe (II) sites formed on the 5%Fe-Bi₄O₅Br₂ photocatalyst and facilitated the activation of H₂O₂ to form oxidative species, which greatly enhanced the degradation efficiency of Tetracycline.

Complexation and enantioselectivity of novel bridge-like uranyl- 2-((1Z,9Z)-9-(2-Hydroxyphenyl)-3,5,6,8-tetrahydrobenzo[h][1,4,7,10] dioxadiazacyclododecin-2-yl)-5-methoxyphenol with chiral organophosphorus pesticide enantiomers of R/S-malathions

Designing new uranyl complexes with enantioselectivity is of great significance for the identification and separation of enantiomers of chiral pesticides. In this paper, a new asymmetric rigid uranyl-2-((1Z,9Z)-9-(2-Hydroxyphenyl)-3,5,6,8-tetrahydrobenzo[h][1,4,7,10] dioxadiaza-cyclododecin-2-yl)-5-methoxyphenol(Uranyl-HTDM) was designed, we used Uranyl-HTDM as a receptor to selectively coordinate with the guests of the chiral organophosphorus pesticide R/S-malathions(R/S-MLTs) to explore the receptor's enatioselectivity recognition of the chiral guests of R/S-MLTs. Density functional theory (DFT) method was used to comprehensively study the complexation mode of the receptor with enantiomers. The results showed that the U of Uranyl-HTDM could coordinate with both the thiophosphoryl sulfur and carbonyl oxygens of R/S-MLTs in different environments, respectively. The thermodynamics calculations further indicated that the receptor could selectively recognize the thiophosphoryl sulfur and carbonyl oxygen atoms of R/S-malathions, and the complexation abilities of Uranyl-HTDM to the R/S-malathions under different solvents were not the same. The smaller the polarity of solvents, the stronger the complexation ability of Uranyl-HTDM with R-malathion, toluene was an ideal solvent with large △G change and enatioselectivity coefficient of 99.55%. The study provides useful references for the design of new uranyl-salophens and for the experimental study on the molecular recognition of chiral organophosphorus pesticides.

A Brief Review of Catalytic Cathode Materials for Na-CO2 Batteries

As an emerging energy storage technology, Na-CO2 batteries with high energy density are drawing tremendous attention because of their advantages of combining cost-effective energy conversion and storage with CO2 clean recycle and utilization. Nevertheless, their commercial applications are impeded by unsatisfactory electrochemical performance including large overpotentials, poor rate capability, fast capacity deterioration, and inferior durability, which mainly results from the inefficient electrocatalysts of cathode materials. Therefore, novel structured cathode materials with efficient catalytic activity are highly desired. In this review, the latest advances of catalytic cathode materials for Na-CO2 batteries are summarized, with a special emphasis on the electrocatalysts for CO2 reduction and evolution, the formation and decomposition of discharge product, as well as their catalytic mechanism. Finally, an outlook is also proposed for the future development of Na-CO2 batteries.