Zhongbiao Wu

Photothermal catalysis offers a light-driven route for N2O abatement by coupling broadband light harvesting with catalytic surface reactions. Here, spinel Co3O4 catalysts were prepared by calcining at 400, 500, and 600 °C (denoted as Co3O4-400, Co3O4-500, and Co3O4-600, respectively). This temperature-controlled synthesis preserved the spinel framework while modulating the local bonding environment surrounding the Co centers. Among the three catalysts, Co3O4-500 exhibited a relatively less-coordinated octahedral Co–O–Co environment, accompanied by modest surface Co2+ enrichment. Light-assisted N2O temperature-programmed desorption showed that Co3O4-500 retained a larger population of thermally stable N2O-related species, while in situ infrared spectroscopy revealed more rapid attenuation of the bands assigned to N–N- and N–O-related vibrations under illumination. Temperature-matched controls further showed that its enhanced activity could not be explained by macroscopic catalyst-bed heating alone. Accordingly, Co3O4-500 achieved 93.5% single-pass N2O conversion and a decomposition rate of 40.82 mmol g–1 h–1 at 1.81 W cm–2 under broadband irradiation. These results associate the photothermal activity of Co3O4 with its local Co–O coordination environment and identify coordination regulation through controlled thermal treatment as a strategy for designing non-noble-metal catalysts for N2O abatement.

Oxide encapsulation has emerged as a generalizable synthetic strategy for constructing metal–oxide catalytic interfaces with tailored electronic properties and enhanced activities, yet the instability of substoichiometric overlayers under oxidative/humid conditions and the inability to engineer active sites at atomic–scale thicknesses substantially limit mechanistic understanding and rational design of encapsulated catalysts. Here, we establish electron buffering as a fundamental synthetic strategy that concurrently stabilizes the classical H2–reduction–induced substoichiometric overlayer and tailors its surface chemistry. By incorporating cerium as a reversible electron buffer into TiO2–derived substoichiometric matrices, we construct the first binary–metal–oxide overlayers with tunable atomic thickness (1–5 layers) on Pd nanoparticles. The Ce 4f levels reversibly donate or accept electrons to compensate for oxidative electron loss, preserving encapsulation stability while enabling active–site engineering at the atomic–scale. This synthetic design achieves unprecedented catalytic activity and durability, activating CO oxidation at near–zero temperature, and operating for over 150 hours under O2–, H2O– and SO2–containing conditions, whereas non–buffered overlayers rapidly collapse and deactivate within 5 hours.

Mitigating the profound environmental impact of greenhouse gas nitrous oxide (N2O) emissions necessitates the design of highly active, low-temperature, and impurity-tolerant decomposition catalysts. In this work, sol-gel-derived neodymium-incorporated nickel oxide (NdxNi) catalysts were systematically developed for direct N2O decomposition. The optimal Nd0.06Ni achieves 90% N2O conversion (T90) at a remarkably low temperature of 275 °C. Compared to bare NiO, it exhibits a drastically suppressed apparent activation energy (Ea) declining from 97.15 to 61.31 kJ/mol, and a 1.5-fold increase in turnover frequency (TOF). In the individual presence of NO, O2, or H2O, Nd0.06Ni exhibited improved impurity resistance relative to pristine NiO, maintaining T90 values within 315–360 °C. However, simultaneous exposure to the three impurities substantially suppressed the N2O conversion, whereas the activity largely recovered after the impurities were removed, indicating reversible inhibition under the present conditions. Crucially, density functional theory (DFT) calculations, underpinned by d-band center analysis, reveal the intrinsic catalytic mechanism: Nd incorporation shifts the d-band center of surface Ni sites downward from −2.41 eV to −2.56 eV. This moderate electronic modulation optimally weakens the over-strong Ni–O bond, substantially reducing the energy required for O2 desorption (from 5.19 to 4.58 eV) and thus accelerating the Ni2+/Ni3+ redox cycle. This work provides fundamental insights and a viable strategy for designing ultra-low-temperature catalysts with improved impurity resistance for practical N2O abatement.

Methane valorization is important for climate change mitigation and sustainable carbon utilization, but conventional nonoxidative coupling of methane (NOCM) suffers from the high activation barrier of CH4, limited product selectivity, and rapid coking-induced deactivation. Herein, we develop a spark discharge−dielectric barrier discharge (DBD) coupled plasma-catalytic system for the selective conversion of high-concentration methane to ethylene. Spark discharge first activates CH4 and preferentially converts it to C2H2, while a downstream catalyst bed, maintained at 100−130 °C by residual discharge heat, enables acetylene semihydrogenation to C2H4. A coupled DBD unit is further introduced for in situ carbon removal and catalyst regeneration. Among the tested catalysts, impregnation−reduction-derived 0.1Pd-5Cu/γ-Al2O3-R with atomically dispersed Pd exhibited the best performance, achieving 72.38% CH4 conversion, 72.19% C2H4 selectivity, 92.48% acetylene-based C2H4 selectivity, and a C2H4 space-time yield of 69.97 mmol·g·−1·h−1 at 36.2 kJ·L−1. With DBD-assisted regeneration, efficient NOCM operation was maintained for 630 min. Mechanistic analyses associate the enhanced ethylene selectivity with highly dispersed Pd sites and their electronic modulation by predominantly low-valent Cu species, which suppress overhydrogenation and facilitate ethylene desorption.

Valorization of nitrous oxide (N2O), a potent greenhouse gas, through cooperative reforming with light alkanes offers a promising route toward carbon-negative hydrogen production. Here, we report a Ru1+n/ZnO catalyst that integrates isolated ruthenium single atoms (Ru1) with subnanometre ruthenium nanoparticles (Run), enabling cascade N2O valorization coupled with propane dry reforming. The catalyst reduces noble-metal cost by ∼70% compared with Ir-based benchmarks while delivering markedly enhanced hydrogen production (145.1 mol H2 kgcat–1 h–1) together with stable operation for at least 72 h. Mechanistic studies reveal that densely anchored Ru1 sites in close proximity to Run electronically modulate the nanoparticles toward a more metallic state, promoting hydrocarbon activation. Meanwhile, CHx* intermediates formed on Run are rapidly consumed through reforming with O* species generated on satellite Ru1 via N2O activation, enabling an efficient cascade reaction pathway that suppresses side reactions and enhances hydrogen generation. This work demonstrates a cooperative single-atom–nanoparticle catalytic strategy for greenhouse-gas valorization and efficient hydrogen production, providing insights into the rational design of multifunctional reforming catalysts.

Achieving efficient catalytic oxidation of propane remains a challenge in pollution control. High-entropy oxides (HEOs) are promising catalysts for this reaction owing to their abundant defects and high thermal stability. To further improve their performance, we investigated the divergent effects of acid treatment on HEO catalysts for propane oxidation. The catalyst treated with citric acid (HEO-CA) exhibited enhanced activity, lowering T90 by 13 °C, whereas the catalyst treated with phosphoric acid (HEO-PA) increased T90 by 11 °C. Characterization revealed that both acid treatments introduced additional defects. On HEO-CA, the residual surface organic species were readily decomposed, allowing oxygen vacancies to promote the activation of gaseous O2 and to enhance the availability of reactive lattice oxygen. In contrast, although HEO-PA possessed more oxygen vacancies, the retained phosphate species hindered oxygen migration and lattice oxygen replenishment. This ultimately suppressed deep oxidation and degraded catalytic performance.

Vanadium-based catalysts are widely considered for the synergistic removal of NOx and chlorinated organics in waste incineration and sintering flue gases, where alkali metals can accumulate and compromise catalytic stability and emission safety. Herein, experiments and DFT calculations were combined to elucidate the effect of potassium on the multipollutant conversion efficiency, synergistic reaction mechanism, and toxic byproduct formation over a V2O5–MoO3/TiO2 catalyst. Potassium species preferentially neutralized Brønsted acid sites and reduced the availability of surface hydroxyl groups, thereby weakening NH3 activation and chlorinated organic adsorption/activation. DFT calculations further revealed that K2O adsorption at the V–Mo interfacial site hindered interfacial electron transfer and lattice oxygen activation, suppressing Mars-van Krevelen deep oxidation. Consequently, potassium deposition decreased NOx conversion and chlorinated organic oxidation by 20% and 90% at 350 °C compared to V2O5–MoO3/TiO2, respectively, and promoted the formation of incomplete oxidation products, including chloromethane and benzaldehyde. Our findings demonstrate that alkali poisoning not only lowers catalytic activity but also redirects reaction pathways toward secondary byproduct formation, highlighting the need to design alkali-tolerant catalysts that preserve acid-redox coupling under alkali-rich flue-gas conditions.