Constructing High-performance Cobalt-based Environmental Catalysts from Spent Lithium-Ion Batteries: Unveiling Overlooked Roles of Copper and Aluminum from Current Collectors.

Converting spent lithium-ion batteries (LIBs) cathode materials into environmental catalysts has drawn more and more attention. Herein, we fabricated a Co3O4-based catalyst from spent LiCoO2 LIBs (Co3O4-LIBs) and found that the role of Al and Cu from current collectors on its performance is nonnegligible. The density functional theory calculations confirmed that the doping of Al and/or Cu upshifts the d-band center of Co. A Fenton-like reaction based on peroxymonosulfate (PMS) activation was adopted to evaluate its activity. Interestingly, Al doping strengthened chemisorption for PMS (from -2.615 eV to -2.623 eV) and shortened Co-O bond length (from 2.540 Å to 2.344 Å) between them, whereas Cu doping reduced interfacial charge-transfer resistance (from 28.347 kΩ to 6.689 kΩ) excepting for the enhancement of the above characteristics. As expected, the degradation activity toward bisphenol A of Co3O4-LIBs (0.523 min-1) was superior to that of Co3O4 prepared from commercial CoC2O4 (0.287 min-1). Simultaneously, the reasons for improved activity were further verified by comparing activity with catalysts doped Al and/or Cu into Co3O4. This work reveals the role of elements from current collectors on the performance of functional materials from spent LIBs, which is beneficial to the sustainable utilization of spent LIBs.

Fabrication of p-n Heterostructured Photocatalysts with Triazine-Based Covalent Organic Framework and CuInS2 for High-Efficiency CO2 Reduction.

The application of covalent organic frameworks (COFs) for the photocatalytic reduction of CO2 is mostly limited by severe charge recombination and low sunlight utilization. Herein, a triazine-based COF with an electron-rich and large π-conjugated system (TCOF) was employed as a building block and integrated with CuInS2 (CIS) to construct a noble-metal-free and high-efficiency photocatalyst for CO2 reduction. The in situ growth of CIS nanosheets on TCOF creates a p-n heterojunction, named CIS@TCOF. Compared with TCOF, the CIS@TCOF heterostructure exhibits a dramatically boosted photocatalytic performance in the reduction of CO2. The produced HCOOH yield over 10 wt % CIS@TCOF can be up to 171.2 µmol g-1 h-1 under visible light irradiation with good reproducibility, which is about 3 times as high as that over TCOF. Further in-depth studies indicate that the introduction of CIS not only enhances the visible light utilization but also restrains the recombination of photogenerated electron-hole pairs efficiently and facilitates the photoinduced charge transfer via the p-n heterojunction system due to the unique structural and compositional features. This research shows the great potential of COFs as efficient photocatalytic carbon fixation materials and provides a versatile route to construct semiconductor-COF heterostructures for photocatalysis.

A density functional theory study on the mechanism of toluene from dimethylcyclopentane catalyzed by the [GaH]2+ active site of Ga-ZSM-5.

The ONIOM (ωb97xd/6-31G(d,p):pm6) method was used to study the reaction mechanism of dimethylcyclopentane to toluene by the [GaH]2+ active site of Ga-ZSM-5. The results showed that the rate-determining step in the dimethylcyclopentane aromatization process is the ring expansion process. Compared to those of methylcyclopentane to benzene (D. D. Zhang, H. Y. Liu, L. X. Ling, H. R. Zhang, R. G. Zhang, P. Liu and B. J. Wang, Phys. Chem. Chem. Phys., 2021, 23, 10988-11003.), the free energy barriers of dimethylcyclopentane to toluene are significantly decreased, indicating that toluene is easier to produce than benzene, which confirmed the experimental results that a higher proportion of toluene than benzene is produced in the MTA process.

Constructing extrinsic oxygen vacancy on the surface of photocatalyst as CO2 and electrons reservoirs to improve photocatalytic CO2 reduction activity.

Constructing own oxygen vacancies in the photocatalysts is a very promising method to improve their photocatalytic CO2 reduction activity. However, some catalysts have excellent stabilities, making it difficult for them to construct their own oxygen vacancies. To simplify the above difficulty of stable photocatalysts, constructing extrinsic oxygen vacancies on their surface as a novel idea is proposed. Here, a stable TiO2 nanosheet is chosen as a research object, we uniformly deposited BiOCl quantum dots on their surface via a simple adsorption-deposition method. It is found that BiOCl quantum dots are able to simultaneously self-transform into defective BiOCl with many oxygen vacancies when the photocatalyst is performed photocatalytic CO2 reduction. These extrinsic oxygen vacancies can act as "CO2 and photo-generated electrons reservoirs" to improve CO2 capture and accelerate the separation of photogenerated electrons and holes. For the above reasons, the modified TiO2 showed obvious enhancement of photocatalytic CO2 reduction compared to pristine TiO2 and BiOCl. This work may open a new avenue to broaden the use of oxygen vacancies in the process of photocatalytic CO2 reduction.

Metal-Organic Framework Derived Bi-O-Sn/C Nanostructure: Tailoring the Adsorption Site of Dominant Intermediate for Highly Efficient CO2 Electroreduction to Formate.

Electrochemical CO2 reduction into high-value-added formic acid/formate is an attractive strategy to mitigate global warming and achieve energy sustainability. However, the adsorption energy of most catalysts for the key intermediate *OCHO is usually weak, and how to rationally optimize the adsorption of *OCHO is challenging. Here, an effective Bi-Sn bimetallic electrocatalyst (Bi1 -O-Sn1 @C) where a Bi-O-Sn bridge-type nanostructure is constructed with O as an electron bridge is reported. The electronic structure of Sn is precisely tuned by electron transfer from Bi to Sn through O bridge, resulting in the optimal adsorption energy of intermediate *OCHO on the surface of Sn and the enhanced activity for formate production. Thus, the Bi1 -O-Sn1 @C exhibits an excellent Faradaic efficiency (FE) of 97.7% at -1.1 V (vs RHE) for CO2 reduction to formate (HCOO- ) and a high current density of 310 mA cm-2 at -1.5 V, which is one of the best results catalyzed by Bi- and Sn-based catalysts reported previously. Impressively, the FE exceeds 93% at a wide potential range from -0.9 to -1.4 V. In-situ ATR-FTIR, in-situ Raman, and DFT calculations confirm the unique role of the bridge-type structure of Bi-O-Sn in highly efficient electrocatalytic reduction of CO2 into formate.

Boosting Low-Temperature CO2 Hydrogenation over Ni-based Catalysts by Tuning Strong Metal-Support Interactions.

Rational design of low-cost and efficient transition-metal catalysts for low-temperature CO2 activation is significant and poses great challenges. Herein, a strategy via regulating the local electron density of active sites is developed to boost CO2 methanation that normally requires >350 °C for commercial Ni catalysts. An optimal Ni/ZrO2 catalyst affords an excellent low-temperature performance hitherto, with a CO2 conversion of 84.0 %, CH4 selectivity of 98.6 % even at 230 °C and GHSV of 12,000 mL g-1 h-1 for 106 h, reflecting one of the best CO2 methanation performance to date on Ni-based catalysts. Combined a series of in situ spectroscopic characterization studies reveal that re-constructing monoclinic-ZrO2 supported Ni species with abundant oxygen vacancies can facilitate CO2 activation, owing to the enhanced local electron density of Ni induced by the strong metal-support interactions. These findings might be of great aid for construction of robust catalysts with an enhanced performance for CO2 emission abatement and beyond.

Scalable and Consolidated Microbial Platform for Rare Earth Element Leaching and Recovery from Waste Sources.

Chemical methods for the extraction and refinement of technologically critical rare earth elements (REEs) are energy-intensive, hazardous, and environmentally destructive. Current biobased extraction systems rely on extremophilic organisms and generate many of the same detrimental effects as chemical methodologies. The mesophilic methylotrophic bacterium Methylobacterium extorquens AM1 was previously shown to grow using electronic waste by naturally acquiring REEs to power methanol metabolism. Here we show that growth using electronic waste as a sole REE source is scalable up to 10 L with consistent metal yields without the use of harsh acids or high temperatures. The addition of organic acids increases REE leaching in a nonspecific manner. REE-specific bioleaching can be engineered through the overproduction of REE-binding ligands (called lanthanophores) and pyrroloquinoline quinone. REE bioaccumulation increases with the leachate concentration and is highly specific. REEs are stored intracellularly in polyphosphate granules, and genetic engineering to eliminate exopolyphosphatase activity increases metal accumulation, confirming the link between phosphate metabolism and biological REE use. Finally, we report the innate ability of M. extorquens to grow using other complex REE sources, including pulverized smartphones, demonstrating the flexibility and potential for use as a recovery platform for these critical metals.

Highly efficient atomic hydrogen-mediated electrochemical hydrodehalogenation of trichloroacetic acid on 3D hierarchical multi-transition metal selenides.

Halogenated organic compounds as highly focused emerging contaminants pose a long-lasting threat to human health and the aquatic environment due to their high toxicities and strong anti-biodegradation characteristics. Electrochemical hydrodehalogenation (ECHD) is a promising technology with a low-carbon footprint to remove halogenated organic compounds while suffering from a lack of efficient and robust earth-abundant electrocatalysts. Herein, by integrating two kinds of transition metal dichalcogenides (i.e., MoSe2 nanosheet and Ni3Se2 nanowire) into a conductive 3D porous network nickel foam, we obtained a hierarchical architecture (MoSe2/Ni3Se2@NF) that promises high surface area, fast charge transfer and efficient mass transfer. The interface-confined epitaxial growth of Ni3Se2 nanowires on nickel foam provides abundant sites for the vertical growth of MoSe2 nanosheets, which endows MoSe2 with maximal accessible active edge sites to participate in the ECHD process. Benefiting from such a hierarchical 3D porous configuration, trichloroacetic acid (5 mg/L) was removed over 95% by MoSe2/Ni3Se2@NF at - 1.2 V vs. SCE after 1 h, which dramatically outperformed that for NF (20%) and Ni3Se2@NF (53.2%). The major contributor to such boosted performance is the adsorbed atomic hydrogen (*H) generated during water splitting via suppressing hydrogen-hydrogen dimerization, as evidenced by radical quenching experiments and electron paramagnetic resonance spectroscopy. This study offers appealing opportunities for tailoring the catalytic performance of noble-metal-free heterogeneous catalysts for various applications that require noble-metal catalysts.

Electrospun Carbon Nanofibers and Their Applications in Several Areas.

Carbon nanofibers (CNFs) have a broad spectrum of applications, including sensor manufacturing, electrochemical catalysis, and energy storage. Among different manufacturing methods, electrospinning, due to its simplicity and efficiency, has emerged as one of the most powerful commercial large-scale production techniques. Numerous researchers have been attracted to improving the performance of CNFs and exploring new potential applications. This paper first discusses the working theory of manufacturing electrospun CNFs. Next, the current efforts in upgrading the properties of CNFs, such as pore architecture, anisotropy, electrochemistry, and hydrophilicity, are discussed. The corresponding applications due to the superior performances of CNFs are subsequently elaborated. Finally, the future development of CNFs is discussed.

Peroxymonocarbonate activation via Co nanoparticles confined in metal-organic frameworks for efficient antibiotic degradation in different actual water matrices.

Traditional advanced oxidation processes suffer from low availability of ultrashort lifetime radicals and declining stability of catalysts. Co nanoparticles in hollow bimetallic metal-organic frameworks (Co@MOFs) were synthesized via a solvothermal method. Nanoconfinement and peroxymonocarbonate (PMC) degradation system endows Co@MOFs with high catalytic activity and stability even in the actual water matrices. The nanocomposites exhibited 100-200 nm polyhedron structure with irregular nanocavity between the 20 nm shell and multicores. Co nanoparticles were completely encapsulated by the FeIII-MOF-5 shell according to the X-ray diffraction and photoelectron spectra. Both 0.8 nm micropores and 3.6 nm mesopores were proven to be present. The yolk-shell Co@MOFs exhibited higher catalytic performance than that of Co nanoparticles, hollow FeIII-MOF-5 and its core-shell counterpart toward PMC activation during sulfamethoxazole degradation. The catalytic activities of Co@MOFs for the activation of unsymmetrical peroxides (PMC and peroxymonosulfate) were much higher than those for the symmetrical peroxides (H2O2 and persulfate) and the heterogeneous catalysis was dominant in the Co@MOFs activated H2O2 and PMC systems. The MOF stability was the highest and metal leakages were the least in the activated PMC system among the four peroxides because of mild reaction conditions and the alkalescent solution (pH = 8.3-8.4). Furthermore, the high removal efficiencies (>94%) and degradation rates could be maintained in the different actual water matrices due to the confinement effects. The contributions of carbonate and hydroxyl radicals were primary for sulfamethoxazole degradation, and superoxide anion and singlet oxygen also played essential roles according to scavenging experiments and time-series spin-trapping electron spin resonance spectra. Six degradation pathways were proposed according to 26 intermediate identification and the pharmacophores of more than 80% intermediates were destroyed, which would benefit subsequent biological treatment. Successful combination of nanoconfinement and PMC might provide a new effective solution for pollution remediation.

Visible-light-induced photocatalytic CO2 reduction over zirconium metal organic frameworks modified with different functional groups.

The reduction of CO2 into high value-added chemicals and fuels by a photocatalytic technology can relieve energy shortages and the environmental problems caused by greenhouse effects. In the current work, an amino-functionalized zirconium metal organic framework (Zr-MOF) was covalently modified with different functional groups via the condensation of Zr-MOF with 2-pyridinecarboxaldehyde (PA), salicylaldehyde (SA), benzaldehyde (BA), and trifluoroacetic acid (TA), named Zr-MOF-X (X = PA, SA, BA, and TA), respectively, through the post-synthesis modification. Compared with Zr-MOF and Zr-MOF-TA, the introduction of PA, SA, or BA into the framework of Zr-MOF can not only enhance the visible-light harvesting and CO2 capture, but also accelerate the photogenerated charge separation and transfer, thereby improving the photocatalytic ability of Zr-MOF for CO2 reduction. These results indicate that the modification of Zr-MOF with electron-donating groups can promote the photocatalytic CO2 reduction. Therefore, the current work provides an instructive approach to improve the photocatalytic efficiency of CO2 reduction through the covalent modification of MOFs.

Study on enhancement of hemoglobin antitoxic ability modified with chromium and ruthenium.

Hemoglobin is essential for carrying oxygen (O2) in the blood. However, its ability to bind excessively to carbon monoxide (CO) makes it susceptible to CO poisoning. To reduce the risk of CO poisoning, Cr-based heme and Ru-based heme were selected from among many transition metal-based hemes based on their characteristics of adsorption conformation, binding intensity, spin multiplicity, and electronic properties. The results showed that hemoglobin modified by Cr-based heme and Ru-based heme had strong anti-CO poisoning abilities. The Cr-based heme and Ru-based heme exhibited much stronger affinity for O2 (-190.67 kJ/mol and -143.18 kJ/mol, respectively) than Fe-based heme (-44.60 kJ/mol). Moreover, Cr-based heme and Ru-based heme exhibited much weaker affinity for CO (-121.50 kJ/mol and -120.88 kJ/mol, respectively) than their affinity for O2, suggesting that they were less likely to cause CO poisoning. The electronic structure analysis also supported this conclusion. Additionally, molecular dynamics analysis showed that hemoglobin modified by Cr-based heme and Ru-based heme was stable. Our findings offer a novel and effective strategy for enhancing the reconstructed hemoglobin's ability to bind O2 and reduce its potential for CO poisoning.

Catalytic CO2 Capture via Ultrasonically Activating Dually Functionalized Carbon Nanotubes.

High energy consumption and high cost have been the obstacles for large-scale deployment of all state-of-the-art CO2 capture technologies. Finding a transformational way to improve mass transfer and reaction kinetics of the CO2 capture process is timely for reducing carbon footprints. In this work, commercial single-walled carbon nanotubes (CNTs) were activated with nitric acid and urea under ultrasonication and hydrothermal methods, respectively, to prepare N-doped CNTs with the functional group of -COOH, which possesses both basic and acid functionalities. The chemically modified CNTs with a concentration of 300 ppm universally catalyze both CO2 sorption and desorption of the CO2 capture process. The increases in the desorption rate achieved with the chemically modified CNTs can reach as high as 503% compared to that of the sorbent without the catalyst. A chemical mechanism underlying the catalytic CO2 capture is proposed based on the experimental results and further confirmed by density functional theory computations.

Intelligent Chip-Controlled Smart Oxygen Electrodes for Constructing Rechargeable Zinc-Air Batteries with Excellent Energy Efficiency and Durability.

High-performance rechargeable oxygen electrodes are key devices for realizing high-specific-energy batteries, including zinc-air and lithium-air batteries. However, these batteries have severe problems of premature decay in energy efficiency by serious corrosion, wide charge-discharge gap, and catalyst peeling off. Herein, we propose a "smart dual-oxygen electrode", which is composed of an intelligent switch control module + heterostructured Fe1Ni3-LDH/PNCNF OER catalysis electrode layer + ion conductive | electronic insulating membrane + Pt/C ORR catalysis electrode layer, where OER and ORR layers are automatically switched by the intelligent switch control module as required. This smart dual-oxygen electrode offers an ultralow energy efficiency decay rate of 0.0067% after 300 cycles during cycling, much lower than that of the commercial Pt/C electrode (1.82%). The assembled rechargeable zinc-air battery (RZAB) displays a super narrow voltage gap and achieves a high energy efficiency of 71.7%, far higher than that of the existing RZABs (about 50%). Therefore, this strategy provides a complete solution for designing various high-performance metal-air secondary batteries.

Mesoporous MgO enriched in Lewis base sites as effective catalysts for efficient CO2 capture.

Capturing CO2 has become increasingly important. However, wide industrial applications of conventional CO2 capture technologies are limited by their slow CO2 sorption and desorption kinetics. Accordingly, this research is designed to overcome the challenge by synthesizing mesoporous MgO nanoparticles (MgO-NPs) with a new method that uses PEG 1500 as a soft template. MgO surface structure is nonstoichiometric due to its distinctive shape; the abundant Lewis base sites provided by oxygen vacancies promote CO2 capture. Adding 2 wt % MgO-NPs to 20 wt % monoethanolamine (MEA) can increase the breakthrough time (the time with 90% CO2 capturing efficiency) by ∼3000% and can increase the CO2 absorption capacity within the breakthrough time by ∼3660%. The data suggest that MgO-NPs can accelerate the rate and increase CO2 desorption capacity by up to ∼8740% and ∼2290% at 90 °C, respectively. Also, the excellent stability of the system within 50 cycles is verified. These findings demonstrate a new strategy to innovate MEA absorbents currently widely used in commercial post-combustion CO2 capture plants.

Ethane Dehydrogenation over the Core-Shell Pt-Based Alloy Catalysts: Driven by Engineering the Shell Composition and Thickness.

Pt-based catalysts as the commercial catalysts in ethane dehydrogenation (EDH) face one of the main challenges of realizing the balance between coke formation and catalytic activity. In this work, a strategy to drive the catalytic performance of EDH on Pt-Sn alloy catalysts is proposed by rationally engineering the shell surface structure and thickness of core-shell Pt@Pt3Sn and Pt3Sn@Pt catalysts from a theoretical perspective. Eight types of Pt@Pt3Sn and Pt3Sn@Pt catalysts with different Pt and Pt3Sn shell thicknesses are considered and compared with the industrially used Pt and Pt3Sn catalysts. Density functional theory (DFT) calculations completely describe the reaction network of EDH, including the side reactions of deep dehydrogenation and C-C bond cracking. Kinetic Monte Carlo (kMC) simulations reveal the influences of the catalyst surface structure, experimentally related temperatures, and reactant partial pressures. The results show that CHCH* is the main precursor for coke formation, and Pt@Pt3Sn catalysts generally have higher C2H4(g) activity and lower selectivity compared to those of Pt3Sn@Pt catalysts, which is attributed to the unique surface geometrical and electronic properties. 1Pt3Sn@4Pt and 1Pt@4Pt3Sn are screened out as catalysts exhibiting excellent performance; especially, the 1Pt3Sn@4Pt catalyst has much higher C2H4(g) activity and 100% C2H4(g) selectivity compared to those of 1Pt@4Pt3Sn and the widely used Pt and Pt3Sn catalysts. The two descriptors C2H5* adsorption energy and reaction energy of its dehydrogenation to C2H4* are proposed to qualitatively evaluate the C2H4(g) selectivity and activity, respectively. This work facilitates a valuable exploration for optimizing the catalytic performance of core-shell Pt-based catalysts in EDH and reveals the great importance of the fine control of the catalyst shell surface structure and thickness.

Emerging catalysts for the ambient synthesis of ethylene glycol from CO2 and its derivatives.

Ethylene glycol (EG), a useful chemical raw material, has been widely applied in many aspects of modern society. The conventional preparation of ethylene glycol mainly uses the petroleum route at high temperatures and pressure. More and more approaches have been developed to synthesize EG from CO2 and its derivatives under mild conditions. In this review, the ambient synthesis of EG from thermocatalysis, photocatalysis, and electrocatalysis is highlighted. The coal-to-ethylene glycol technology, one of the typical thermal catalysis routes for EG preparation, is relatively mature. However, it still faces some problems to be solved in industrialization. The recent progress in the development of coal-to-ethylene glycol technology is introduced. The main focus is on how to realize the preparation of EG under mild conditions. The strategies include doping promoters, modification of supports, design of catalysts with special structures, etc. Furthermore, the emerging technological progress of photocatalytic and electrocatalytic ethylene glycol synthesis under ambient conditions is introduced. Compared with the thermal catalytic reaction, the reaction conditions are milder. However, there are still many problems in large-scale production. Finally, we propose future development issues and related prospects for the ambient synthesis of EG using different catalytic routes.

[EMmim][NTf2 ]-a Novel Ionic Liquid (IL) in Catalytic CO2 Capture and ILs' Applications.

Ionic liquids (ILs) have been used for carbon dioxide (CO2 ) capture, however, which have never been used as catalysts to accelerate CO2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf2 ]. The IL can universally catalyze both CO2 sorption and desorption of all the chemisorption-based technologies. As demonstrated in monoethanolamine (MEA) based CO2 capture, even with the addition of only 2000 ppm IL catalyst, the rate of CO2 desorption-the key to reducing the overall CO2 capture energy consumption or breaking the bottleneck of the state-of-the-art technologies and Paris Agreement implementation-can be increased by 791% at 85 °C, which makes use of low-temperature waste heat and avoids secondary pollution during CO2 capture feasible. Furthermore, the catalytic CO2 capture mechanism is experimentally and theoretically revealed.