Unlocking bimetallic active sites via a desalination strategy for photocatalytic reduction of atmospheric carbon dioxide.

Ultrathin two-dimensional (2D) metal oxyhalides exhibit outstanding photocatalytic properties with unique electronic and interfacial structures. Compared with monometallic oxyhalides, bimetallic oxyhalides are less explored. In this work, we have developed a novel top-down wet-chemistry desalination approach to remove the alkali-halide salt layer within the complicated precursor bulk structural matrix Pb0.6Bi1.4Cs0.6O2Cl2, and successfully fabricate a new 2D ultrathin bimetallic oxyhalide Pb0.6Bi1.4O2Cl1.4. The unlocked larger surface area, rich bimetallic active sites, and faster carrier dynamics within Pb0.6Bi1.4O2Cl1.4 layers significantly enhance the photocatalytic efficiency for atmospheric CO2 reduction. It outperforms the corresponding parental matrix phase and other state-of-the-art bismuth-based monometallic oxyhalides photocatalysts. This work reports a top-down desalination strategy to engineering ultrathin bimetallic 2D material for photocatalytic atmospheric CO2 reduction, which sheds light on further constructing other ultrathin 2D catalysts for environmental and energy applications from similar complicate structure matrixes.

Hydroxylamine mediated Fenton-like interfacial reaction dynamics on sea urchin-like catalyst derived from spent LiFePO4 battery.

Herein, we converted spent LiFePO4 battery to the sea urchin-like material (SULM) with a highly efficient and environment-friendly method, which can contribute to building a zero-waste city. With SULM as a Fenton-like catalyst, a highly-efficient degradation process was realized for organic pollutants with interface and solution synergistic effect. In our SULM+NH2OH+H2O2 Fenton-like system, NH2OH can effectively promote the interface iron (Fe(Ⅲ)/Fe(Ⅱ)) and solution iron (Fe(Ⅲ)/Fe(Ⅱ)) redox cycle, thus promoting the generation of reactive oxygen species (ROS). However, the ROS generation process and organic pollutants degradation pathway with the presence of NH2OH remains a puzzle. Here the detailed ROS generation mechanism and pollutants degradation pathway have been illustrated carefully based on experimental exploration and characterization. Therein, hydroxyl radicals (·OH) and singlet oxygen (1O2) are the main ROS for oxidizing and degrading organic pollutants. Notably, 1O2 can be converted from superoxide radicals (·O2) in SULM+NH2OH+H2O2 system. This study not only demonstrates the strategy of "trash-to-treasure" and "waste-to-control-waste" to simultaneously reduce the hazardous release from industrial solid waste and organic wastewater, it also provides new mechanistic insights for NH2OH mediated Fenton-like redox system.

Bi2O3/BiO2 Nanoheterojunction for Highly Efficient Electrocatalytic CO2 Reduction to Formate.

Heterostructure engineering plays a vital role in regulating the material interface, thus boosting the electron transportation pathway in advanced catalysis. Herein, a novel Bi2O3/BiO2 heterojunction catalyst was synthesized via a molten alkali-assisted dealumination strategy and exhibited rich structural dynamics for an electrocatalytic CO2 reduction reaction (ECO2RR). By coupling in situ X-ray diffraction and Raman spectroscopy measurements, we found that the as-synthesized Bi2O3/BiO2 heterostructure can be transformed into a novel Bi/BiO2 Mott-Schottky heterostructure, leading to enhanced adsorption performance for CO2 and *OCHO intermediates. Consequently, high selectivity toward formate larger than 95% was rendered in a wide potential window along with an optimum partial current density of -111.42 mA cm-2 that benchmarked with the state-of-the-art Bi-based ECO2RR catalysts. This work reports the construction and fruitful structural dynamic insights of a novel heterojunction electrocatalyst for ECO2RR, which paves the way for the rational design of efficient heterojunction electrocatalysts for ECO2RR and beyond.

Converting Spent LiFePO4 Battery into Zeolitic Phosphate for Highly Efficient Heavy Metal Adsorption.

Developing efficient recycling technologies for large-scale spent batteries is the key to build a zero-waste city. Herein, a [Al8.5Fe0.5P12O48]·[C24H72N16]·[Li·4H2O]·[12H2O] (AlFePO-Li) zeolite, crystallizing in space group I4̅3m with a = 16.6778(3) Å, has been constructed via the hydrothermal treatment of spent LiFePO4 battery. Benefiting from the three-dimensional 12-member-ring channels in its structure and chemical adsorption, excellent Pb2+ removal capacity up to 723.8 mg g-1 has been achieved. Detailed adsorption mechanism study revealed that the cation exchange capacity is significantly contributed by ion exchange of the protonated organic amine cations in the zeolite channel and the protons from the framework dangling phosphate group. This work demonstrates a novel method of reutilizing spent LIBs to construct zeolite for heavy metal removal. It is of great importance to achieve sustainable development based on the "resource utilization" and "trash-to-treasure" strategy.

Converting loess into zeolite for heavy metal polluted soil remediation based on "soil for soil-remediation" strategy.

Both soil erosion and soil contamination pose critical environmental threats to the Chinese Loess Plateau (CLP). Green, efficient and feasible remediation technologies are highly demanded to meet these challenges. Herein we propose a unique "soil for soil-remediation" strategy to remediate the heavy metal polluted soil in CLP by converting loess into zeolite for the first time. With a simple template-free route, the natural loess can be converted into cancrinite (CAN) type of zeolite. A highly crystalline CAN was obtained via hydrothermal treatment at 240 oC for 48 h, with a precursor alkalinity of Na/(Si+Al)> 2.0. The as-synthesized CAN zeolite exhibits excellent remediation performance for Pb(II) and Cu(II) polluted soil. Plant assay experiment demonstrates that CAN can significantly restrain the uptake and accumulation of Pb(II) and Cu(II) ions in vegetables, with a high removal efficiency up to 90.7% and 81.4%, respectively. This work demonstrates a "soil for soil-remediation" strategy to utilize the natural loess for soil remediation in CLP, which paves the way for developing green and sustainable remediation eco-materials with local loess as raw materials.

High-efficiency core-shell magnetic heavy-metal absorbents derived from spent-LiFePO4 Battery.

Search for simple and efficient recycling methods to utilize spent lithium-ion batteries is crucial for achieving sustainable resource development and reducing the hazardous materials released from the spent batteries. Herein, we have developed a new strategy to utilize the spent LiFePO4 batteries by utilizing the cathode plate as raw material to synthesize mesoporous core-shell adsorbent Mm@SiO2 (Mm denoted as the magnetic material) through a simple alkaline leaching process. The as-converted material exhibits excellent adsorption capacity when it has been used to remove heavy metal ions in heavy metal polluted water. The adsorption capacities for Cu2+, Cd2+, and Mn2+ have been achieved up to 71.23, 80.31 and 68.73 mg g-1, respectively. The detailed adsorption mechanism has been elucidated with comprehensive characterization techniques, including TEM, XPS, NEXAS, and EXAFS, the edge shared [Cu2O8] bipyramids can be fit against the EXAFS data to represent the atomic-scale local structure after Mm@SiO2 adsorbs Cu2+. The present work demonstrates a novel routine to reutilize the spent lithium batteries, which is of great importance to achieve sustainable development based on the "waste-to-treasure" and "waste-to-control-waste" strategy for simultaneously reducing the hazardous release from industrial solid waste and heavy metal polluted water.