Search

Conversion of CO2 into value-added chemicals is regarded as an effective way to reduce carbon emissions and improve the carbon recycling economy. In the process of hydrogenation of CO2 to CH4, nickel (Ni) has been extensively investigated due to its promising activity and easy availability. However, the inferior performance at low temperatures of Ni-based catalysts and the tendency of sintering at high temperatures lead to a rapid decline in activity, which hinders their large-scale applications. In this study, mesoporous silicas with highly ordered mesoporous structures but different pore symmetries and textural properties have been investigated as supports to synthesize Ni-based catalysts modified by La2O3. The effect of mesoporous symmetries and textural properties of the silica support on catalytic performance has been reasonably revealed. The catalysts supported on optimized silica with bicontinuous three-dimensional cubic pore symmetry exhibit considerably enhanced activity and stability in long-term CO2 methanation, which is attributed to the high dispersion of metal particles and the better mass transfer performance of interconnected mesopores in the silica support. [ABSTRACT FROM AUTHOR]

Product selectivity of solar‐driven CO2 reduction and H2O oxidation reactions has been successfully controlled by tuning the spatial distance between Pt/Au bimetallic active sites on different crystal facets of CeO2 catalysts. The replacement depth of Ce atoms by monatomic Pt determines the distance between bimetallic sites, while Au clusters are deposited on the surface. This space configuration creates a favourable microenvironment for the migration of active hydrogen species (*H). The *H is generated via the activation of H2O on monatomic Pt sites and migrate towards Au clusters with a strong capacity for CO2 adsorption. Under concentrated solar irradiation, selectivity of the (100) facet towards CO is 100 %, and the selectivity of the (110) and (111) facets towards CH4 is 33.5 % and 97.6 %, respectively. Notably, the CH4 yield on the (111) facet is as high as 369.4 μmol/g/h, and the solar‐to‐chemical energy efficiency of 0.23 % is 33.8 times higher than that under non‐concentrated solar irradiation. The impacts of high‐density flux photon and thermal effects on carriers and *H migration at the microscale are comprehensively discussed. This study provides a new avenue for tuning the spatial distance between active sites to achieve optimal product selectivity. [ABSTRACT FROM AUTHOR]

The recovery of valuable metals from spent ternary lithium-ion batteries (LIBs) has recently garnered significant attention due to the imperatives of the circular economy and environmental management. While the reclamation of lithium is generally straightforward, the hydrometallurgical methods most frequently employed for leaching and separating the remaining nickel, cobalt, and manganese from spent electrode material often yield secondary liquid and solid wastes. In this study, we present a mechanochemical strategy aimed at repurposing lithium-removed spent ternary LIBs cathode material as a precursor for perovskite oxides through a straightforward and scalable solid-state high-energy ball-milling synthesis. By optimizing the synthesis procedure, we have obtained a perovskite catalyst composed of LaNi0.6Co0.2Mn0.2O3 with a trace amount of phase-separated surface NiO nanocrystals. This catalyst demonstrates outstanding performance in the low-temperature oxidation of CO, exhibiting no degradation in performance over extended periods of service. Notably, it achieves a T50 of 162 °C and a T90 of 197 °C, which compares favorably with previously reported perovskite catalysts prepared via wet synthesis, utilizing fine chemicals as precursors. This approach not only presents a novel method for valorizing spent ternary LIBs but also expands the repertoire of metal precursors available for oxidation catalysts. [ABSTRACT FROM AUTHOR]

H2O dissociation plays a crucial role in solar-driven catalytic CO2 methanation, demanding high temperature even for solar-to-chemical conversion efficiencies <1% with modest product selectivity. Herein, we report an oxygen-vacancy (Vo) rich CeO2 catalyst with single-atom Ni anchored around its surface Vo sites by replacing Ce atoms to promote H2O dissociation and achieve effective photothermal CO2 reduction under concentrated light irradiation. The high photon flux reduces the apparent activation energy for CH4 production and prevents Vo from depletion. The defects coordinated with single-atom Ni, significantly promote the capture of charges and local phonons at the Ni d-impurity orbitals, thereby inducing more effective H2O activation. The catalyst presents a CH4 yield of 192.75 µmol/cm2/h, with a solar-to-chemical efficiency of 1.14% and a selectivity ~100%. The mechanistic insights uncovered in this study should help further the development of H2O-activating catalysts for CO2 reduction and thereby expedite the practical utilization of solar-to-chemical technologies. This work reports a single-atom Ni incorporated CeO2 catalyst that boosts the efficiency of solar CO2 reduction under concentrated light irradiation. [ABSTRACT FROM AUTHOR]

The unrestricted utilization of antibiotics poses a critical challenge to global public health and safety. Levofloxacin (LEV) and sulfaphenazole (SPN), widely employed broad-spectrum antimicrobials, are frequently detected at the terminal stage of water treatment, raising concerns regarding their potential conversion into detrimental disinfection byproducts (DBPs). However, current knowledge is deficient in identifying the potential DBPs and elucidating the precise transformation pathways and influencing factors during the chloramine disinfection process of these two antibiotics. This study conducts a comprehensive analysis of reaction pathways, encompassing piperazine ring opening/oxidation, Cl-substitution, OH-substitution, desulfurization, and S−N bond cleavage, during chloramine disinfection. Twelve new DBPs were identified in this study, exhibiting stability and persistence even after 24 h of disinfection. Additionally, an examination of DBP generation under varying disinfectant concentrations and pH values revealed peak levels at a molar ratio of 25 for LEV and SPN to chloramine, with LEV contributing 11.5% and SPN 23.8% to the relative abundance of DBPs. Remarkably, this research underscores a substantial increase in DBP formation within the molar ratio range of 1:1 to 1:10 compared to 1:10 to 1:25. Furthermore, a pronounced elevation in DBP generation was observed in the pH range of 7 to 8. These findings present critical insights into the impact of the disinfection process on these antibiotics, emphasizing the innovation and significance of this research in assessing associated health risks. [ABSTRACT FROM AUTHOR]

The development of high‐precision, non‐destructive, and three‐dimensional (3D) in situ imaging of micro‐scale damage inside polymers is extremely challenging. Recent reports suggest that 3D imaging technology based on micro‐CT technology causes irreversible damage to materials and is ineffective for many elastomeric materials. In this study, it is discovered that electrical trees inside silicone gel induced by an applied electric field can induce a self‐excited fluorescence effect. Based on this, high‐precision, non‐destructive, and 3D in situ fluorescence imaging of polymer damages is successfully achieved. Compared with the current methods, the fluorescence microscopic imaging method enables slicing of the sample in vivo with high‐precision operation, realizing the precise positioning of the damaged area. This pioneering discovery paves the way for high‐precision, non‐destructive, and 3D in situ imaging of polymer internal damage, which can solve the problem of internal damage imaging in insulating materials and precision instruments. [ABSTRACT FROM AUTHOR]

Integrating a high proportion of intermittent renewable energy provides a solution for the higher peak-shaving capacity of coal-fired power plants. Oxy-fuel combustion is one of the most promising carbon reduction technologies for coal-fired power plants. This study has proposed a novel oxy-fuel power plant that is coupled with both liquid O2 storage and cold energy recovery systems in order to adapt to the peak-shaving requirements. The liquid O2 storage system uses cheap valley electricity to produce liquid O2 for a later use in the peak period to enhance the peak-shaving capacity. Meanwhile, the cold energy recovery system has been introduced to recover the physical latent energy during the phase change of liquid O2 to increase the power generation in the peak period. Technical economies of three power plants, i.e. a 330 MW (e) oxy-fuel power plant as reference (Case 1), the same power plant coupled with only liquid O2 storage system (Case 2), and the same power plant coupled with both liquid O2 storage and cold energy recovery systems (Case 3), have been analyzed and compared. Thermodynamic performance analysis indicates that the peaking capacity of Case 3 can reach the range of 106.03 to 294.22 MW (e), and the maximum peak-shaving coefficient can be as high as 2.77. Exergy analysis demonstrates that the gross exergy efficiency of Cases 2 and 3 reaches 32.18% and 33.57%, respectively, in the peak period, which are significantly higher than that of 26.70% in Case 1. Economic analysis shows that through selling the liquid O2 and liquid CO2, combined with carbon trading, the levelized cost of electricity (LCOE) of the three cases have been greatly reduced, with the lowest one of 30.90 USD/MWh shown in Case 3. For a comprehensive consideration, Case 3 can be considered a future reference of oxy-fuel power plant with the best thermodynamic and economic performance. [ABSTRACT FROM AUTHOR]