Elucidation of the role of metals in the adsorption and photodegradation of herbicides by metal-organic frameworks.

Here, four MOFs, namely Sc-TBAPy, Al-TBAPy, Y-TBAPy, and Fe-TBAPy (TBAPy: 1,3,6,8-tetrakis(p-benzoic acid)pyrene), were characterized and evaluated for their ability to remediate glyphosate (GP) from water. Among these materials, Sc-TBAPy demonstrates superior performance in both the adsorption and degradation of GP. Upon light irradiation for 5 min, Sc-TBAPy completely degrades 100% of GP in a 1.5 mM aqueous solution. Femtosecond transient absorption spectroscopy reveals that Sc-TBAPy exhibits enhanced charge transfer character compared to the other MOFs, as well as suppressed formation of emissive excimers that could impede photocatalysis. This finding was further supported by hydrogen evolution half-reaction (HER) experiments, which demonstrated Sc-TBAPy's superior catalytic activity for water splitting. In addition to its faster adsorption and more efficient photodegradation of GP, Sc-TBAPy also followed a selective pathway towards the oxidation of GP, avoiding the formation of toxic aminomethylphosphonic acid observed with the other M3+-TBAPy MOFs. To investigate the selectivity observed with Sc-TBAPy, electron spin resonance, depleted oxygen conditions, and solvent exchange with D2O were employed to elucidate the role of different reactive oxygen species on GP photodegradation. The findings indicate that singlet oxygen (1O2) plays a critical role in the selective photodegradation pathway achieved by Sc-TBAPy.

Photoactive Organo-Sulfur Polymers for Hydrogen Generation.

Herein, we report the synthesis of photoactive polymeric organo-sulfur (POS) materials. These polymers absorb light in the ultraviolet/visible and near-infrared region of the solar spectrum, and upon irradiation, they reduce water to hydrogen (H2 ). The decoration of POS materials with nitrile (-CN) groups is found to be the critical factor for enhanced interactions with the co-catalyst, Ni2 P, leading to greater H2 evolution rates compared to the nitrile-free POS material.

Copper metal electrode reversibly hosts fluoride in a 16 m KF aqueous electrolyte.

Fluoride is a promising charge carrier for batteries due to its high charge/mass ratio and small radius. Here, we report commercial copper powder exhibits a reversible capacity of up to 222 mA h g-1 in a saturated electrolyte of 16 m KF. This electrolyte suppresses dissolution of CuF2, the charged product. Furthermore, the KF solid comprised in the Cu electrode facilitates a high initial capacity. Our results showcase the potential of aqueous fluoride batteries using copper as an electrode.

From Copper to Basic Copper Carbonate: A Reversible Conversion Cathode in Aqueous Anion Batteries.

Dual-ion batteries that use anions and cations as charge carriers represent a promising energy-storage technology. However, an uncharted area is to explore transition metals as electrodes to host carbonate in conversion reactions. Here we report the reversible conversion reaction from copper to Cu2 CO3 (OH)2 , where the copper electrode comprising K2 CO3 and KOH solid is self-sufficient with anion-charge carriers. This electrode dissociates and associates K+ ions during battery charge and discharge. The copper active mass and the anion-bearing cathode exhibit a reversible capacity of 664 mAh g-1 and 299 mAh g-1 , respectively, and relatively stable cycling in a saturated mixture electrolyte of K2 CO3 and KOH. The results open an avenue to use carbonate as a charge carrier for batteries to serve for the consumption and storage of CO2 .

Reversible electrochemical conversion from selenium to cuprous selenide.

Using elemental selenium as an electrode, the redox-active Cu2+/Cu+ ion is reversibly hosted via the sequential conversion reactions of Se → CuSe → Cu3Se2 → Cu2Se. The four-electron redox process from Se to Cu2Se produces a high initial specific capacity of 1233 mA h g-1 based on the mass of selenium alone or 472 mA h g-1 based on the mass of Cu2Se, the fully discharged product.

A Dual Plating Battery with the Iodine/[ZnIx (OH2 )4-x ]2-x Cathode.

Plating battery electrodes typically deliver higher specific capacity values than insertion or conversion electrodes because the ion charge carriers represent the sole electrode active mass, and a host electrode is unnecessary. However, reversible plating electrodes are rare for electronically insulating nonmetals. Now, a highly reversible iodine plating cathode is presented that operates on the redox couples of I2 /[ZnIx (OH2 )4-x ]2-x in a water-in-salt electrolyte. The iodine plating cathode with the theoretical capacity of 211 mAh g-1 plates on carbon fiber paper as the current collector, delivering a large areal capacity of 4 mAh cm-2 . Tunable femtosecond stimulated Raman spectroscopy coupled with DFT calculations elucidate a series of [ZnIx (OH2 )4-x ]2-x superhalide ions serving as iodide vehicles in the electrolyte, which eliminates most free iodide ions, thus preventing the consequent dissolution of the cathode-plated iodine as triiodides.