This work constructed an immobilized laccase- peroxymonosulfate (PMS) activation synergistic catalytic system for enhancing the efficient removal of reactive blue 19 (RB19). Superparamagnetic CuFe2O4/kaolin (CF/K) composites were prepared by one-step solvothermal and calcination methods and then modified with chitosan as immobilized carriers for laccase. The enzyme activity of CuFe2O4/kaolin-CTS-Laccase (CF/K-CTS-Lac) could reach 316.3 U/g under optimal immobilization conditions of 3 h and 2.6 mg/mL. CF/K-CTS-Lac exhibited improved pH stability and thermal stability in comparison to free laccase. The CF/K-CTS-Lac/PMS synergistic catalytic system achieved 98.4 % decolourization of RB19 within 90 min, which was 1.7 and 1.9 times higher than that of the CF/K-CTS-Lac system and CF/K-CTS/PMS system, respectively. Enhanced RB19 degradation efficiency attributed to synergistic catalysis by immobilized laccase and PMS activation. Free radical quenching experiments showed that hydroxyl radicals (center dot OH), sulfate radicals (SO4 center dot-), superoxide radicals (center dot O2- ) and singlet oxygen (1O2) were involved in the synergistic catalytic system, with center dot O2- and 1 O 2 playing a major role. Our investigations are expected to provide new insights into the construction of synergistic catalytic systems for pollutants.

Heterogeneous catalysts promoting efficient production of reactive species and dynamically stabilized electron transfer mechanisms for peroxomonosulfates (PMS) still lack systematic investigation. Herein, a more stable magnetic layered double oxides (CFLDO/N-C), was designed using self-polymerization and high temperature carbonization of dopamine. The CFLDO/N-C/PMS system effectively activated PMS to remove 99% (k=0.737 min-1) of tetracycline (TC) within 10 min. The CFLDO/N-C/PMS system exhibited favorable resistance to inorganic anions and natural organics, as well as satisfactory suitability for multiple pollutants. The magnetic properties of the catalyst facilitated the separation of catalysts from the liquid phase, resulting in excellent reproducibility and effectively reducing the leaching of metal ions. An electronic bridge was constructed between cobalt (the active platform of the catalyst) and PMS, inducing PMS to break the O-O bond to generate the active species. The combination of static analysis and dynamic evolution confirmed the effective adsorption of PMS on the catalyst surface as well as the strong radical-assisted electron transfer process. Eventually, we further identified the sites where the reactive species attacked the TC and evaluated the toxicity of the intermediates. These findings offer innovative insights into the rapid degradation of pollutants achieved by transition metals in SR-AOPs and its mechanistic elaboration.

Various popular large organic cations have been extensively used as the essential additives in the perovskite precursor solution due to their satisfactory passivation effect but may produce the low-n value (n <= 2) 2D perovskite phases with undesired distribution. Meanwhile, the remaining easy oxidation of Sn2+ and the p-type self-doping in the perovskites are also detrimental to the ultimate photovoltaic properties and stability of tin (Sn)-based perovskite solar cells (PSCs). Here, 3AMPYSnI4 crystals (3AMPY = 3-(aminomethyl)pyridinium)) are designed and applied to adjust the crystallization process and the phase distribution of the Sn-based perovskite. Consequently, the strong coordination interaction between 3AMPY2+ and 3D perovskite components and the introduced nucleation sites by 3AMPYSnI4 crystals not only decreases the low-n value 2D phase and increases 3D perovskite phase, but also inhibits the oxidation of Sn2+ and the self-p-doping in the Sn-based perovskites, resulting in lower trap density and non-radiative recombination loss, faster carrier extraction and transfer, and higher stability for 2D-3D Sn-based PSCs. As a result, the optimized devices deliver an increased power conversion efficiency from an initial 10.91% to 13.28% and retain 96.0% of their original performance for more than 3000 h in the nitrogen (N2) atmosphere. The strong coordination interaction between 3AMPY2+ and 3D perovskite components as well as the introduced nucleation sites by 3AMPYSnI4 crystals adjust the phase distribution of 2D and 3D perovskite phase, accompanied by the suppressed Sn2+ oxidation and self-p-doping, resulting in lower trap density and non-radiative recombination loss, faster carrier extraction and transfer, and higher stability for 2D-3D Sn-based PSCs. image

Additive engineering plays a pivotal role in achieving high-quality light-absorbing layers for high-performance and stable perovskite solar cells (PSCs). Various functional groups within the additives exert distinct regulatory effects on the perovskite layer. However, few additive molecules can synergistically fulfill the dual functions of regulating crystallization and passivating defects. Here, we custom-synthesized 2-ureido-4-pyrimidone (UPy) organic small molecules with diverse functional groups as additives to modulate crystallization and defects in perovskite films via the Michael addition reaction. Theoretical and experimental investigations demonstrate that the -OH groups in UPy exhibit significant effects in fixing uncoordinated Pb2+ ions, passivation of lead-iodide antisite defects, alleviating hysteresis, and reducing non-radiative recombination. Furthermore, the enhanced C=O and -NH2 motifs interact with the A-site cation via hydrogen bonding, which relieves residual strain and adjusts crystal orientation. This strategy effectively controls perovskite crystallization and passivates defects, ultimately enhancing the quality of perovskite films. Consequently, the open-circuit voltage of the UPy-based p-i-n PSCs reaches 1.20 V, and the fill factor surpasses 84 %. The champion device delivers a power conversion efficiency of 25.75 %. Remarkably, the unencapsulated device maintained 96.9 % and 94.5 % of its initial efficiency following 3,360 hours of dark storage and 1,866 hours of 1-sun illumination, respectively.

Deep-level traps at the buried interface of perovskite and energy mismatch problems between the perovskite layer and heterogeneous interfaces restrict the development of ideal homogenized films and efficient perovskite solar cells (PSCs) using the one-step spin-coating method. Here, we strategically employed sparingly soluble germanium iodide as a homogenized bulk in-situ reconstruction inducing material preferentially aggregated at the perovskite buried interface with gradient doping, markedly reducing deep-level traps and withstanding local lattice strain, while minimizing non-radiative recombination losses and enhancing the charge carrier lifetime over 9 µs. Furthermore, this gradient doping assisted in modifying the band diagram at the buried interface into a desirable flattened alignment, substantially mitigating the energy loss of charge carriers within perovskite films and improving the carrier extraction equilibrium. As a result, the optimized device achieved a champion power conversion efficiency of 25.24% with a fill factor of up to 84.65%, and the unencapsulated device also demonstrated excellent light stability and humidity stability. This work provides a straightforward and reliable homogenization strategy of perovskite components for obtaining efficient and stable PSCs.

Transition metals as activators of peroxymonosulfate (PMS) are effective catalysts for the degradation of organic pollutants. The construction of multiple active sites is the key for enhanced PMS activation. Herein, we prepared ZIF-8 derived Fe- Ni nitrogen-carbon with highly dispersed bimetallic active sites, achieving a small amount of highly efficient catalytic performance for tetracycline (TC) degradation. The Fe and Ni elements in the catalyst were uniformly dispersed, resulting in a high specific surface area of 367 m2/g. Even at low metal concentrations (Fe=0.83%, Ni=0.33%), Fe-Ni-N-C/PMS showed superior performance in degrading total carbon TC. Its reaction rate constant was 1.71 times higher than Fe-N-C/PMS and 2.13 times higher than Ni-N-C/PMS. This significant improvement was attributed to the synergistic effect of the bimetallic components and the highly dispersed active sites. The mechanism was proposed that Fe-Ni-N-C activates PMS to generate hydroxyl radicals (●OH), sulfate radicals (SO●−4), superoxide radicals (O●−2), and singlet oxygen (1O2) to further degrade TC. Among them, 1O2 and SO●−4were the main reactive oxygen species. This work has provided a new insight into the development of transition metals with multiple active sites for the degradation of organic pollutants.

Two-terminal (2T) perovskite-based tandem solar cells (TSCs) arouse burgeoning interest in breaking the Shockley-Queisser (S-Q) limit of single-junction solar cells by combining two subcells with different bandgaps. However, the highest certified efficiency of 2T perovskite-based TSCs (33.9%) lags behind the theoretical limit (42-43%). A vital challenge limiting the development of 2T perovskite-based TSCs is the transparent recombination layers/interconnecting layers (RLs) design between two subcells. To improve the performance of 2T perovskite-based TSCs, RLs simultaneously fulfill the optical loss, contact resistance, carrier mobility, stress management, and conformal coverage requirements. In this review, the definition, functions, and requirements of RLs in 2T perovskite-based TSCs are presented. The insightful characterization methods applicable to RLs, which are inspiring for further research on the RLs both in 2T perovskite-based two-junction and multi-junction TSCs, are also highlighted. Finally, the key factors that currently limit the performance enhancement of RLs and the future directions that should be continuously focused on are summarized.

Flexible perovskite solar cells (f-PSCs) as a promising power source have grabbed surging attention from academia and industry specialists by integrating with different wearable and portable electronics. With the development of low-temperature solution preparation technology and the application of different engineering strategies, the power conversion efficiency of f-PSCs has approached 24%. Due to the inherent properties and application scenarios of f-PSCs, the study of strain in these devices is recognized as one of the key factors in obtaining ideal devices and promoting commercialization. The strains mainly from the change of bond and lattice volume can promote phase transformation, induce decomposition of perovskite film, decrease mechanical stability, etc. However, the effect of strain on the performance of f-PSCs has not been systematically summarized yet. Herein, the sources of strain, evaluation methods, impacts on f-PSCs, and the engineering strategies to modulate strain are summarized. Furthermore, the problems and future challenges in this regard are raised, and solutions and outlooks are offered. This review is dedicated to summarizing and enhancing the research into the strain of f-PSCs to provide some new insights that can further improve the optoelectronic performance and stability of flexible devices.

Metal halide hybrid perovskite solar cells (PSCs) have received considerable attention over the past decade owing to their potential for low‐cost, solution‐processable, earth‐abundant, and high‐performance superiority, increasing power conversion efficiencies of up to 25.7%. Solar energy conversion into electricity is highly efficient and sustainable, but direct utilization, storage, and poor energy diversity are difficult to achieve, resulting in a potential waste of resources. Considering its convenience and feasibility, converting solar energy into chemical fuels is regarded as a promising pathway for boosting energy diversity and expanding its utilization. In addition, the energy conversion–storage integrated system can efficiently sequentially capture, convert, and store energy in electrochemical energy storage devices. However, a comprehensive overview focusing on PSC‐self‐driven integrated devices with a discussion of their development and limitations remains lacking. Here, focus is on the development of representative configurations of emerging PSC‐based photo‐electrochemical devices including self‐charging power packs, unassisted solar water splitting/CO 2 reduction. The advanced progresses in this field, including configuration design, key parameters, working principles, integration strategies, electrode materials, and their performance evaluations are also summarized. Finally, scientific challenges and future perspectives for ongoing research in this field are presented.

We synthesized the magnetic recyclable Ti3C2 derived N-TiO2@C@Fe3O4 for photo-Fenton degradation of organic pollutants through high-temperature calcination and solvothermal methods. Ti3C2 was first calcined into TiO2@C with a homogeneous titanium source and a two-dimensional carbon framework. Then the magnetic nanoparticles (Fe3O4) were loaded by solvothermal method, which effectively solved the problem of repeated circulation of powder catalysts. N-TiO2@C@Fe3O4 could be used as an excellent co-catalyst to improve the decomposition efficiency of H2O2 in advanced oxidation processes (AOPs). This significantly reduced the amount of H2O2 and Fe2+ in the photo-Fenton system. The N-TiO2@C@Fe3O4 photo-Fenton system could degrade 96.5% of Rhodamine B (RhB) within 300 s and maintain a recycling rate of more than 90% after 10 cycles. This system also had favorable applicability to the same wastewater of antibiotics. This mechanism was proposed that the N-TiO2@C@Fe3O4 photo-Fenton system activated H2O2 to generate hydroxyl radicals (.OH) and superoxide rad-icals (.O2?) to further attack RhB. This research provided novel insights for the photo-Fenton collaborative cat-alytic system to achieve advanced oxidation treatment of pollutants in the water environment.

A novel three-dimensional multi-level porous g-C3N4 modified MXene-derived TiO2@C aerogel (g-C3N4/ TiO2@C aerogel) was synthesized for NO removal. Through SEM analysis, 2D g-C3N4 and 2D Ti3C2 nanosheets were constructed into an interconnected macroscopic framework with continuous macropores via ice template. OD TiO2 nanoparticles uniformly covered 2D C nanosheets with irregular mesopores and macropores in in-situ oxidation of Ti3C2 nanosheets by calcination via TEM analysis. g-C3N4/ TiO2@C aerogel for photocatalytic activation of hydrogen peroxide (H2O2) had an excellent efficiency of 90.7% for NO removal at parts per million level. This efficiency was 4.9 times and 7.8 times that of gC3N4/TiO2@C aerogel and H2O2 individually, due to the synergy between photocatalysis and H2O2 oxidation. Meantime, g-C3N4/TiO2@C aerogel exhibited an enhanced performance compared with g-C3N4 nanosheet (55.7%) and TiO2@C aerogel (38.5%). It was attributed to the large specific surface area (93.82 m2/g) with hierarchical mesoporous and macroporous structure and the 2D/OD/2D heterojunction of g-C3N4/TiO2@C aerogel, further enhancing electron-hole separation. The mechanism was hypothesized that g-C3N4/TiO2@C aerogel activated H2O2 to generate hydroxyl radicals (center dot OH) and superoxide radicals (.O2-) for oxidation of NO. (c) 2021 Elsevier Inc. All rights reserved.

Background: Based on the advanced oxidation process of transition metal activated peroxymonosulfate (PMS), a heterogeneous catalyst with simple synthesis strategy and high efficiency was prepared. It was used to remove refractory organic pollutants. Methods: We designed a biochar modified cobalt-iron bimetallic composite catalyst (BC@CFC) via co-precipitation and calcination methods using biomass and cobalt-iron layered double hydroxide as precursors. Significant Findings: BC1@CF2C exhibited a unique multi-level porous layered structure, which reasonably reduced the agglomeration of cobalt-iron composite and increased the specific surface area. This allowed the catalyst to create more exposed active sites and favorably activate PMS, with a rapid and efficient degradation of tetracycline (TC) in 5 min (92.49%+/- 0.21%) and 30 min (96.63%+/- 1.68%). BC1@CF2C was magnetic and easy to recover, it maintained a superior TC removal rate (about 90%) after 5 cycles. This remarkable performance was benefited from the synergistic effect of cobalt-iron bimetal to enhance the activation effect of PMS, which led to the production of sulfate free radicals (SO4 center dot-) and hydroxyl free radicals (center dot OH) to further attack TC. BC@CFC possessed the advantages of being environment-friendly, high catalytic activity and sustainability, which could be of great value in environmental application. (C) 2022 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

This work explored an effective treatment method for removing NO from simulated flue gas at normal temperature. We synthesized accordion-like MXene-derived TiO2@C coupled with g-C3N4 (TiO2@C/g-C3N4) via one-step calcination utilizing Ti3AlC2, fluoride salts and melamine as raw materials in CO2 atmosphere. One-step calcination process simultaneously achieved the etch of Al layers of Ti3AlC2 by molten fluoride salts, the generation of g-C3N4 with melamine as precursor and the oxidation of Ti3C2 by CO2. TiO2@C/g-C3N4 for photocatalytic activation of hydrogen peroxide (H2O2) had as high as 94.0% removal rate of NO at parts per million level in a normal temperature environment. This efficiency was 5.3 times and 8.0 times that of TiO2@C/g-C3N4 and H2O2 individually, due to the synergy between photocatalysis and H2O2 oxidation. Meantime, TiO2@C/g-C3N4 exhibited an enhanced performance compared with g-C3N4 (40.3%) and TiO2@C (64.1%) for Z-type heterojunction accelerating the separation of electron-hole pairs. The mechanism was proposed that Z-type TiO2@C/g-C3N4 heterojunction activated H2O2 under visible light to generate hydroxyl radical and superoxide radical for oxidation of NO.

In order to further enhance the activation performance of peroxymonosulfate (PMS) an efficient and recyclable magnetic recyclable catalyst was successfully fabricated by co-precipitation and hydrothermal methods. We designed commercial hexagonal sheet boron nitride (C-BN) and boron nitrogen micro-nanotubes (BNMTs) to anchor CoFe2O4 nanoparticles (C-BN@CoFe2O4/BNMTs@CoFe2O4). Compared with the smooth hexagonal C-BN, the abundant pores and oxygen-containing groups of BNMTs could effectively increase the loading of CoFe2O4 and enrich the active sites. Under optimal conditions, the BNMTs@CoFe2O4/PMS system could rapidly and efficiently degrade 92.7% of oxytetracycline (OTC) within 5 min. In addition, the strong binding force between BNMTs and CoFe2O4 enabled favorable regeneration efficiency after 5 cycles (87.6%). This mechanism was proposed to activate PMS by BNMTs@CoFe2O4 to generate sulfate free radicals (SO4•-) and hydroxyl free radicals (·OH) to further attack OTC. Our survey results were expected to provide new insights for the rational design and application of boron nitride-based materials and transition metal/PMS systems for environmental remediation.