The key to high C2+ selectivity in CO2RR is precise control over the adsorption and activation of key intermediates. However, existing catalyst designs often lack atomic‑level control over the surface chemical microenvironment. In this work, a copper-based precursor derived from dicyandiamide undergoes in situ transformation under electrochemical CO2 reduction conditions to form an active copper catalyst containing both lattice-doped nitrogen and surface-amidated nitrogen. The catalyst exhibits outstanding C2+ production performance, achieving an ethylene Faradaic efficiency of 79.6 ± 3.6%, a partial current density of 477.6 mA·cm−2, and demonstrates long-term stability over 75 h in a flow cell. In situ characterization and theoretical calculations reveal that the performance enhancement originates from electronic structure regulation, which promotes the formation of covalent intermediates that facilitate the reaction. Lattice nitrogen acts as an electron anchor, modulating the d‑band center of copper sites, while surface nitrogen in situ evolves into a dynamic amide‑bond intermediate under reaction potentials that significantly lowers the energy barrier，thereby selectively directing the C−C coupling pathway toward ethylene.

Sensitive and quantitative monitoring of volatile organic compounds (VOCs) is critical for evaluating treatment effectiveness and mitigating pollution issues. Microbial fuel cells (MFCs) have emerged as a promising platform for VOC sensing; however, their practical application remains limited by poor sensitivity and biofilm susceptibility to toxicants. Quorum sensing (QS) can favorably modulate the intrinsic properties of biofilms by coordinating cell-to-cell communication. In this work, two typical QS signaling molecules, short-chain (C6-HSL) and long-chain (C12-HSL) acyl-homoserine lactones (AHLs), were introduced into MFCs, designated as MFC-C6 and MFC-C12, respectively, to improve the detection of recalcitrant VOC chlorobenzene (CB). AHL addition strengthened the linear correlation between the voltage response and CB concentration, increasing the coefficient of determination from 0.945 in the MFC-blank to 0.960–0.982 in the AHL-treated systems. Moreover, the AHL-treated biosensors exhibited greater electrochemical stability during repeated CB exposure, as evidenced by a smaller variation in the maximum power density. Compared with MFC-C12, MFC-C6 exhibited 1.66-fold superior sensitivity, primarily owing to its higher and more uniformly distributed cell viability throughout the biofilm depth. Metagenomic analysis revealed 8.39% higher abundance of genes related to the QS pathway in MFC-C6 than in MFC-C12. Genes involved in the AI-1 signaling pathway showed apparent differences in abundance among the biosensors, suggesting an important role of AI-1-mediated QS in CB sensing. Furthermore, the enrichment of genes associated with AHL synthesis and sensing, conductive nanowires, and c-type cytochromes contributed to the exceptional sensing performance. These findings provide valuable insights into biofilm regulation for developing efficient CB-monitoring biosensors.

The low density of active sites, poor light absorption and rapid recombination of photogenerated carriers often suppress photocatalytic activity and impede practical applications. Oxygen vacancies (OVs), as unique crystal defects, can improve the performance of photocatalysts for refractory pollutant purification. Herein, a series of SnO2 photocatalysts with tunable OVs concentrations were synthesized via a facile hydrothermal method. Under 50 % relative humidity, an initial toluene concentration of 50 ppm and 60 min of UV irradiation, SnO2 prepared hydrothermally for 24 h with abundant OVs achieved excellent toluene removal efficiency of 92.6 %. The remarkable photocatalytic performance of the catalyst was attributed to the modulation of local electronic structure by OVs. In particular, OVs not only narrowed the bandgap of SnO2, enhancing absorption of longer wavelength light, but also served as trapping sites that hindered recombination of photogenerated charge carriers. Moreover, density functional theory calculations revealed that electron migration in SnO2 was facilitated by OVs, promoting subsequent photocatalytic redox reactions. During toluene elimination, the accelerated formation of ·OH radicals driven by OVs played an important role in increasing the yield of various intermediate products. This work provides valuable insights for developing efficient photocatalysts for pollutant abatement.

Cuprous oxide (Cu2O) is one of the most promising catalysts for electrochemical conversion of CO2 into value-added C2 products. The efficiency of CO2-to-C2 conversion is highly dependent on the Cu2O crystal plane orientation and the corresponding adsorbed *CO species. Herein, we constructed high-index crystal planes (311) in Cu2O (CO-Cu2O) via a facile self-selective CO-induced strategy under a CO atmosphere, which was verified by high-resolution transmission electron microscopy (HR-TEM) and atomic force microscopy (AFM) results. By exploiting the high surface energy of the high index crystal planes, *CO species are stabilized in CO-Cu2O during CO2RR, resulting in exceptional catalytic performance for CO2-to-C2 products. In situ infrared spectroscopy revealed that both atop-type (*COatop) and hollow-type (*COhollow) adsorption of *CO species occurred on the CO-Cu2O. The asymmetric C-C coupling energy barrier between *COatop and *COhollow in (311) crystal plane decreases by 47.8 % compared to the symmetric coupling of *COatop in conventional (100) crystal planes. Consequently, the Faradaic efficiency of C2 products generated with CO-Cu2O was increased by as high as 100 % compared to that with pristine Cu2O. (c) 2025 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Abstract Direct air capture (DAC) is critical to achieve carbon neutrality, yet current technologies face significant barriers to widespread, cost-effective deployment. Amine-based electric swing adsorption (ESA) offers a promising low-energy, steam-free pathway, but its efficiency is fundamentally limited by an inherent 2:1 amine-to-CO 2 stoichiometric penalty. Here, we overcome this bottleneck by engineering a point defect-mediated proton trapping network into ESA sorbents, enabling a 1:1 amine-CO 2 stoichiometry. Our engineered sorbent achieves a CO 2 uptake of 6.57 mmol g −1 from 400 ppm CO 2 , a 28.8% improvement over the state-of-the-art sorbents. Regeneration is achieved with a low energy input of 3.4 GJ t −1 and exhibits a CO 2 release rate 48% faster than conventional thermal methods. N 5- d GA remains stable under 0-80% relative humidity fluctuations and at a gas velocity of 1 m s −1 . Techno-economic analysis projects DAC operating costs of $48-62 t −1 using renewable electricity, up to 78% lower than temperature swing adsorption DAC and below the $100 t −1 CO 2 target. This work presents a sorbent design and ESA process, establishing a scientifically rigorous and economically viable pathway towards gigaton-scale DAC deployment.

Microbial electrolysis cells (MECs) exhibit notable potential for treating refractory chlorinated organic pollutants by creating favorable redox conditions for microbial activity. However, the high sensitivity of biofilm properties to environmental fluctuations limits practical MEC applications. In this study, we investigated the effects of N-acyl-homoserine lactone (AHL)-mediated quorum sensing on MEC performance for chlorobenzene (CB) biodegradation and elucidated the underlying mechanisms. N-butyryl homoserine lactone (C4-HSL) and N-hexanoyl homoserine lactone (C6-HSL) enhanced CB removal during the start-up and operation phases. The reaction rate constants of AHL-treated groups (0.0937-0.5672 h-1) were significantly higher than those of the control group (0.0830-0.3906 h-1), accompanied by 23%-35% improvements in average dechlorination efficiencies. Of the tested AHLs, C4-HSL showed a more pronounced enhancement in biofilm characteristics. It promoted extracellular polymeric substance production and modulated its composition, thus strengthening biofilm resistance to CB stress and facilitating the formation of a robust biofilm with high cell viability. In addition to enriching Achromobacter (7.06%) and Thermomonas (8.75%), C4-HSL induced greater functional potential for cathodic electron uptake than C6-HSL, with a 2.85-fold increase in ccmG(dsbE) abundance and 1.79-4.38-fold enrichment of type IV pilus assembly genes, while also elevating the abundance of electron transport chain genes (237.51-3876.86 versus 42.26-1298.89 RPKM). Moreover, benzoate degradation and citrate cycle pathways were identified as key processes involved in CB elimination. Our findings provide mechanistic insights into how AHLs influence MEC efficacy based on biofilm structural and functional analyses, thereby advancing the deployment of MECs for efficient groundwater purification.

Novel bioelectrodes are being developed to advance the applications of bioelectrocatalytic technology in various energy and environmental scenarios. However, concerns about the sustainability of engineered electrodes during prolonged operation is keeping raised. This study proposes a novel bioelectrode healing strategy via in situ electrode reconstruction on biofilms. The amount of viable cells in healed bioelectrode decreases by 24.23% because of the extreme conditions of strong acid (pH 0.1) and ultrahigh current density (-4.4 to 8.5 × 105 mA m-2) during the redeposition of sponge-like polyaniline@carbon nanotube; however, it quickly recovers to 1.88-fold that of the unhealed bioelectrode. Compared with the control, the healed bioelectrode attains a 2.61-fold toluene degradation kinetics (2.71 h-1), a 1.36-fold power density (401.4 mW m-2), and a 1.09-fold Coulombic efficiency (14.69%), which are also considerably higher than the literature results. The energy cost for electrode healing (19.05 J) accounted for ∼4.7% of the energy recovered in the following operation, thus confirming the energy efficiency of the healing strategy. In addition, the output voltage of the healed bioelectrode decreases by 17.1% at the end of a 60-day operation, with the corresponding decrement being 41.0% for the unhealed control. Furthermore, the elevated concentrations of ATP, NADH, and c-type cytochromes, along with the upregulated genes related to intracellular and extracellular electron transfer, are found to be the driving forces behind the superior and durable performance.

Carbon capture, utilization and storage is critical for achieving deep decarbonization in hard-to-abate sectors such as steel and cement. The conventional monoethanolamine (MEA)-based absorption technology for CO2 capture is well-established but has a high energy penalty. Catalyst-assisted CO2 desorption offers a promising solution to reduce energy consumption. However, single metal oxide catalysts suffer from low electron transfer rates, thereby hindering their catalytic efficiency. To address this issue, a metal oxide-metal composite catalyst, Fe2O3-Fe, was designed to boost the proton-coupled electron transfer effect by facilitating ohmic contact between Fe and Fe2O3. The CO2 desorption efficiency was enhanced by 130% compared with the non-catalyzed process using only 0.1 wt% of the catalyst. The best performance was achieved with Fe2O3-Fe-700, which achieved CO2 desorption of 186 mmol and a 48% reduction in energy consumption for MEA regeneration. Density functional theory calculations indicate that Fe2O3-Fe has a higher charge density than Fe2O3, with a stretched C-N bond and a 47.2% reduction in the proton transfer energy barrier. Moreover, the as-developed catalyst maintains longterm stability during repeated CO2 absorption-desorption cycles. This work provides valuable insights into the development of efficient and stable catalysts for CO2 capture.

Bioelectrochemistry enables refractory chlorobenzene (CB) degradation, but electron transfer limitations in bioelectrodes hinder efficiency. To overcome this, a synergistic strategy combining pore engineering and redox chemistry in a polyaniline@carbon nanotube (PANI@CNT) scaffold electrode was introduced to enhance electron transfer and directional control for CB degradation. Structure-activity analysis showed that the P-C4 electrode, with a pore size matching microbial cell, prepared at a 15 mV s- 1 scan rate and a 1:400 CNT-to-aniline ratio, achieved the highest CB degradation. Furthermore, reductive and oxidative dechlorination pathways were found at different redox potentials. At the optimal potentials, -0.5 and + 0.5 V (vs. Ag/AgCl), the CB degradation kinetics reached 1.29 h- 1 and 0.82 h- 1, respectively. Meanwhile, the highest dechlorination efficiency within 6 h was 96.15 % at -0.5 V, while the highest mineralization efficiency was 82.19 % at + 0.5 V. Overall, this strategy not only enhances CB degradation but also broadens bioelectrode applications.

Electrochemical CO2 reduction reaction holds the promise of achieving carbon neutrality. However, precise design of catalysts to obtain active sites for CO2 conversion into specific products poses considerable challenges. In this work, we report a Ce doping strategy to stabilize the electron cloud (i.e., delocalization state) of oxygen bridged adjacent Cu atoms, which can effectively boost the selectivity of ethylene (C2H4) products. Theoretical calculations showed that Ce2Cu20Ox not only lowers the C-C coupling energy barrier, but also substantially enhances the Cu-O interaction for the favorable formation of *OCHCH2, thus promoting hydrogenation to C2H4. Combining theoretical and experimental analysis, we demonstrate that the favorability of O-C bond cleavage facilitates the formation of C2H4. Consequently, the Ce2Cu20Ox catalyst exhibited an excellent C2H4 Faradaic efficiency of 71.6 % at -400 mA cm- 2 with remarkable stability. Further studies showed that this strategy of modulating the electron density of the Cu sites could also be extended to other transition metal systems, as evidenced by similar correlations between electronic structure and reaction kinetics.

The electrocatalytic reduction of carbon dioxide (CO2RR) by copper oxide-based materials is conducive to the formation of high value-added products, but their activities and selectivities remain unsatisfactory. Organic ligand modification is a promising strategy to achieve a high CO2RR activity. Here, the modification of Cu2O with 1-butyl-3-methylimidazolium chloride (Bmim-Cu2O) enhanced the adsorption of reaction intermediates and improved the stability of the catalyst in the CO2RR, which displays a high Faradaic efficiency of approximate to 85% to C2+ products with a current density as large as approximate to 352.5 mA cm(-2). In situ characterization reveals a stronger *CO signal with bridge configuration and a stronger *OCCHO signal over Bmim-Cu2O than unmodified Cu2O and can improve the stability during electrochemical CO2 reduction. Density functional theory calculations show that local molecular modulation can effectively regulate the electronic structure of Cu2O and enhance the adsorption of *CO and *CHO intermediates through the stabilization of a noncovalent interaction, which can greatly promote the asymmetric *CO-*CHO coupling in the electrochemical reaction process.

This study proposes a switching operating mode that alternates between microbial fuel cell (MFC) and microbial electrolysis cell (MEC) to restore the biofilm activity and organic pollutant degradation capacity in bioelectrochemical systems (BESs) during prolonged operation. After the model switching, the toluene degradation kinetics in BESs equipped with graphite sheet (GS) and polyaniline@carbon nanotubes (PANI@CNTs) bioanodes were elevated by 2.10 and 3.14 times, respectively. Nevertheless, the amount of active biomass in the GS and PANI@CNTs bioanodes only increased by 1.04 and 1.05 times, with the PANI@CNTs bioanode consistently outperforming in hierarchical biofilm activity and redox properties. Additionally, the distribution of functional genes across the dominant genera revealed their roles in extracellular electron transfer and the four steps of toluene degradation (primary oxidation, ring-opening, intermediate oxidation, and tricarboxylic acid cycle). Furthermore, the cooperation of substrate exchange among Pseudomonas, Alicycliphilus, and Acidovorax in the MFC mode evolved to interactions among Acidovorax, Alicycliphilus, and Geobacter in the MEC mode, which attributed to the nonlinear relationship between active biomass and pollutant degradation capacity. These results provide insights into the operating mode and interspecific interactions of BESs, with implications for practical applications.

CO2 emissions from industrial processes are becoming a growing global concern due to their impact on climate change. Catalyst-aided amine solvent regeneration is an effective approach for achieving low-energy carbon capture. Existing desorption catalysts regenerate amine solutions by accelerating proton transfer during CO2 desorption, but limited proton transfer efficiency under alkaline conditions leads to inevitable deactivation of active sites. Herein, we developed TiO2/Ti3C2, a TiO2 nano-islands structured catalyst via in situ oxidation of Ti3C2Tx MXene nanosheets. The remaining MXene enhances electron transfer between TiO2 nano-islands, promoting CO2 desorption-induced solvent regeneration through proton-coupled electron transfer effect via Raman spectroscopy and low-temperature electron paramagnetic resonance experiments. Theoretical calculation demonstrates that TiO2/Ti3C2 reduce the energy barrier of solvent regeneration by 44.9 % compared to the non-catalytic scenario. The CO2 desorption rate increased by 150 %, while the relative energy penalty of the solvent regeneration decreased by 75 %. The regeneration temperature was reduced from 120 degrees C to 98 degrees C with an amine-based biphasic solvent, effectively preventing similar to 28 % of amine degradation. Additionally, TiO2/Ti3C2 demonstrates exceptional stability, showing negligible performance degradation and structural changes after 10 cycles. This work offers valuable insights for designing catalysts to achieve efficient and robust CO2 capture.

Solid amine adsorbents with low energy penalties and optimum capacities are potential candidates for the efficient capture of CO2 from flue gas. As the organic amine type and porous supports are essential factors influencing the performance of amine-based adsorbents, the associated mechanism between the zeolite supports and appended amines must be investigated. In this study, a series of amine-functionalized zeolites were synthesized by incorporating amines of varying molecular lengths into zeolite supports with different pore diameters. The ratio of molecular backbone length to median pore diameter (phi a/z) was proposed to evaluate the effect of molecule-pore size matching on CO2 capture capacity, kinetics, and thermodynamics. The results demonstrated that the optimal CO2 adsorption ability of zeolites could be achieved by selecting the phi a/z values within the range of 1-2. Among the four adsorbents that possessed outstanding performance for CO2 uptake (diethanolamine@4A, triethylenetetramine@HY, tetraethylenepentamine@MCM-41, pentaethylenehexamine @SBA-15), tetraethylenepentamine@MCM-41 with phi a/z of 1.10 exhibited the highest CO2 adsorption capacity of 1.56mmol g-1 at 25 degrees C. The CO2/N2 selectivity of tetraethylenepentamine@MCM-41 was more than six times higher than that of pristine MCM-41. The adsorption heat of tetraethylenepentamine@MCM-41 was lower than the typical value for chemisorption, indicating that its regeneration process was more energy efficient and stable. Here, we have revealed the size matching mechanism between zeolite supports and amines and provided scientific guidance for the preparation of effective and low-cost amine-based adsorbents.

Effective treatment of chlorobenzene (CB)-contaminated waste air is crucial, although biological methods are often constrained by mass transfer limitations and biodegradability. This study presents an innovative two-phase partitioning biotrickling filter coupled with magnetic bioenhancement, employing newly developed non-aqueous phase (silicone oil) immobilized polyurethane foams encapsulated in magnetically modified polyhedral hollow spheres. The removal efficiency of chlorobenzene (CB) improved by 15.6% in compared to the immobilized non-aqueous phase (INAPs) group, and by 37.2% in comparison to the control group at the inlet concentration of 150 mg/m3 with a residence time of 60 s. INAPs enhanced CB mass transfer, with kinetic analysis revealing further improvement induced by the magnetic field (MF). INAPs also promoted the secretion of extracellular polymers (EPS) by 26.8%, with enhanced secretion of loosely/tightly bound EPS promoting resistance to environmental stress. Microbial activity was optimized through INAPs that reduce substrate inhibition, with MF providing further microbial activation. The positively associated effects of INAP and MF on the microbial community was observed to lay the foundation for the positive enhancement of the combination. Overall, this study provides theoretical and technical support for the feasible and efficient treatment of industrial chlorinated volatile organic compounds.

The electrochemical carbon dioxide reduction reaction (CO2RR) to high value-added fuels or chemicals driven by the renewable energy is promising to alleviate global warming. However, the selective CO2 reduction to C2 products remains challenge. Cu-based catalyst with the specific Cu0 and Cu+ sites is important to generate C2 products. This work used nitrogen (N) to tune amounts of Cu0 and Cu+ sites in Cu2O catalysts and improve C2-product conversion. The controllable Cu0/Cu+ ratio of Cu2O catalyst from 0.16 to 15.19 was achieved by adjusting the N doping amount using NH3/Ar plasma treatment. The major theme of this work was clarifying a volcano curve of the ethylene Faraday efficiency as a function of the Cu0/Cu+ ratio. The optimal Cu0/Cu+ ratio was determined as 0.43 for selective electroreduction CO2 to ethylene. X-ray spectroscopy and density functional theory (DFT) calculations were employed to elucidate that the strong interaction between N and Cu increased the binding energy of NCu bond and stabilize Cu+, resulting in a 92.3% reduction in the potential energy change for *CO-*CO dimerization. This study is inspiring in designing high performance electrocatalysts for CO2 conversion.

The biofixation of carbon dioxide (CO2) by chemoautotrophic microorganisms has garnered substantial research attention. Zero-valent iron has been considered an outstanding electron donor, however, studies on iron-driven CO2 biofixation remain limited. Brucella sp. WYQ-2 was firstly time isolated and demonstrated efficient CO2 fixation at rate of 4.7 g/(m3·d) using iron as sole electron donor. The optimal culture conditions were 80 g/m3 CO2, 1 g iron, and a neutral pH, the tolerated CO2 concentration was up to 130 g/m3 (66 % v/v). Furthermore, more than 95 % of CO2 was converted to biomass and organic compounds (methane, acetate, and cyclobutanol), and the acetate yield was 36.4 mg/L. Transcriptomic analyses further revealed that three CO2 bioconversion pathways of Wood-Ljungdahl pathway, C4-dicarboxylic acid cycle, and reductive tricarboxylic acid cycle were involved. Overall, this study enriched the species of CO2 reduction and provided a promising candidate for CO2 biofixation in future full-scale applications.

Microbial electrolysis cells (MECs), a promising approach for purifying refractory exhaust, can overcome low purification capacity and poor process resilience of traditional biological treatment technologies. Threedimensional (3D) electrodes are preferred for exhaust-purifying applications owning to their large surface area available for microbial adhesion. In this work, a polypyrrole (PPy)/cellulose-based carbon aerogel (CCA) was synthesized and used as an MEC anode for eliminating toluene. The toluene elimination capacity of PPy/CCA was 71.16 % and 20.74 % higher than that of graphite and CCA, respectively, under optimal conditions with a potential of +0.6 V and an empty bed residence time of 2.0 min. The impacts of the porous 3D structure and the PPy coating on toluene biodegradation were evaluated from a microscopic perspective. The PPy/CCA biofilm was dense and highly active, with uniform cell viability throughout the thickness. The enrichment of Comamonas promoted toluene removal because of the positive correlation of Comamonas abundance with benzoate conversion. A comparison of the relative abundance of genes in functionally important Kyoto Encyclopedia of Genes and Genomes pathways indicated that benzoate conversion was the rate-limiting step in biodegrading toluene. Genes encoding tricarboxylic acid cycle transport proteins and oxidoreductases were beneficial for toluene degradation. Moreover, the shift from cytochrome c- to electrically conductive pili- dominated electron transport mode was believed to facilitate electron transfer. This study sheds light on the mechanisms underlying the enhanced toluene removal by applying anodes with the desirable characteristics, which is conducive to efficiently reducing the volatile organic compounds emitted in exhaust.

Magnetic fields (MF) have been proven efficient in bioaugmentation, and the internal MFs have become competitive because they require no configuration, despite their application in waste gas treatment remaining largely unexplored. In this study, we firstly developed an intensity-regulable bioaugmentation with internal MF for gaseous chlorobenzene (CB) treatment with modified packing in batch bioreactors, and the elimination capacity increased by up to 26%, surpassing that of the external MF. Additionally, the microbial affinity to CB and the packing surface was enhanced, which was correlated with the ninefold increased secreted ratio of proteins/polysaccharides, 43% promoted cell surface hydrophobicity, and half reduced zeta potential. Furthermore, the dehydrogenase content was promoted over 3 times, and CB removal steadily increased with the rising intensity indicating enhanced biofilm activity and reduced CB bioimpedance; this was further supported by kinetic analysis, which resulted in improved cell adhesive ability and biological utilisation of CB. The results introduced a novel concept of adjustable magnetic bioaugmentation and provided technical support for industrial waste gas treatments. Key points • Regulable magnetic bioaugmentation was developed to promote 26% chlorobenzene removal • Chlorobenzene mineralisation was enhanced under the magnetic field • Microbial adhesion was promoted through weakening repulsive forces Graphical abstract

Microbial fuel cell (MFC) could facilitate biodegradation of organic pollutants and recover electric power. To enhance the removal capacity of dimethyl disulfide (DMDS) and steer the sulfur conversion route, a potential steered approach is proposed in this work. Among -0.35 V, -0.16 V, +0.17 V, and +0.73 V (vs. Ag/AgCl) for bioanode acclimation, the potential of -0.35 V is proved to optimally enhance the power generation. Both of the two negative potentials increase the DMDS removal capacity by 1.54-fold, while the potential of -0.35 V is favor for S2- accumulation, and -0.16 V stimulates the yield of S0 by 100 %. Furthermore, the anode potential is found to affect the microbial community and thus steer the MFC performance. Conversely, its steering effect on the transmembrane and extracellular electron transfer groups is limited. Overall, these findings provide fundamental information on rapid DMDS degradation and S0 recovery in MFC.