The development of highly active and durable catalysts for electrochemical reduction of CO2 (ERC) to CH4 in aqueous media is an efficient and environmentally friendly solution to address global problems in energy and sustainability. In this work, an electrocatalyst consisting of single Zn atoms supported on microporous N-doped carbon was designed to enable multielectron transfer for catalyzing ERC to CH4 in 1 M KHCO3 solution. This catalyst exhibits a high Faradaic efficiency (FE) of 85%, a partial current density of −31.8 mA cm–2 at a potential of −1.8 V versus saturated calomel electrode, and remarkable stability, with neither an obvious current drop nor large FE fluctuation observed during 35 h of ERC, indicating a far superior performance than that of dominant Cu-based catalysts for ERC to CH4. Theoretical calculations reveal that single Zn atoms largely block CO generation and instead facilitate the production of CH4.

Synthesizing H2O2 from water and air via a photocatalytic approach is ideal for efficient production of this chemical at small‐scale. However, the poor activity and selectivity of the 2 e− water oxidation reaction (WOR) greatly restricts the efficiency of photocatalytic H2O2 production. Herein we prepare a bipyridine‐based covalent organic framework photocatalyst (denoted as COF‐TfpBpy) for H2O2 production from water and air. The solar‐to‐chemical conversion (SCC) efficiency at 298 K and 333 K is 0.57 % and 1.08 %, respectively, which are higher than the current reported highest value. The resulting H2O2 solution is capable of degrading pollutants. A mechanistic study revealed that the excellent photocatalytic activity of COF‐TfpBpy is due to the protonation of bipyridine monomer, which promotes the rate‐determining reaction (2 e− WOR) and then enhances Yeager‐type oxygen adsorption to accelerate 2 e− one‐step oxygen reduction. This work demonstrates, for the first time, the COF‐catalyzed photosynthesis of H2O2 from water and air; and paves the way for wastewater treatment using photocatalytic H2O2 solution.

Enrichment of uranyl from seawater is crucial for the sustainable development of nuclear energy, but current uranium extraction technology suffers from multiple drawbacks of low sorption efficiency, slow uptake kinetics, or poor extraction selectivity. Herein, we prepared the first example of amidoxime appended metal-organic framework UiO-66-AO by a postsynthetic modification method for rapid and efficient extraction of uranium from seawater. UiO-66-AO can remove 94.8% of uranyl ion from Bohai seawater within 120 min and 99% of uranyl ion from Bohai seawater containing extra 500 ppb uranium within 10 min. The uranyl sorption capacity in a real seawater sample was determined to be 2.68 mg/g. In addition, the recyclability of the UiO-66-AO framework was demonstrated for at least three adsorption/desorption cycles. The origin for the superior sorption capability was further probed by extended X-ray absorption fine structure (EXAFS) analysis on the uranium-sorbed sample, suggesting multiple amidoxime ligands are able to chelate uranyl(VI) ions, forming a hexagonal bipyramid coordination geometry.

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