Exploring active and low-cost transition metal oxides (TMOs) based catalysts for volatile organic compounds (VOCs) abatement is vital for air pollution control technologies. Since 18 oxygen atoms are required for the complete mineralization of a toluene molecule, the participation of a large amount of active oxygen is a key requirement for the catalytic oxidation of toluene. Here, toluene degradation was improved by weakening the Co–O bond strength on the surface of cobalt oxide, so as to increase the amount of active oxygen species, while maintaining the high stability of the catalyst for toluene combustion. The bond strength of Co–O and the amount of surface active O2 was regulated by tuning the pyrolysis temperature. The catalyst’s redox ability and surface oxygen species activity are improved due to the weakening of the Co–O bond strength. It has been demonstrated that active oxygen plays a crucial role in boosting toluene combustion by engineering Co–O strength in cobalt oxide catalysts. This work provides a new understanding of the exploration and development of high-performance TMO catalysts for VOCs abatement.

In situ formed LiF grains are confined and evenly distributed throughout a covalent organic framework (COF) film, which exhibits cooperative effectiveness to greatly stabilize the lithium metal.

It is challenging for selective catalytic reduction (SCR) of NO x by NH 3 due to the coexistence of heavy metal and SO 2 in the flue gas. A thorough probe into deactivation mechanisms is imperative but still lacking. This study unravels unexpected offset effects of Cd and SO 2 deactivation over CeO 2 -WO 3 /TiO 2 catalysts, potential candidates for commercial SCR catalysts. Cd-and SO 2 -copoisoned catalysts demonstrated higher activity for NO x reduction than a Cd-poisoned catalyst but lower than that for an SO 2 -poisoned catalyst. In comparison to SO 2 , Cd had more severe effects on acidic and redox properties, distinctly decreasing the SCR activity. After sulfation of Cd-poisoned catalysts, SO 4 2− preferentially bonded with the surface CdO and released CeO 2 active sites poisoned by CdO, thus reserving the highly active CeO 2 -WO 3 sites and maintaining a high activity. The sulfation of Cd-poisoned catalysts also provided more strong acidic sites, and the synergistic effects between the formed cerium sulfate and CeO 2 contributed to the high-temperature SCR performance. This work sheds light on the deactivation mechanism of heavy metals and SO 2 over CeO 2 -WO 3 /TiO 2 catalysts and provides an innovative pathway for inventing high-performance SCR catalysts, which have great resistance to heavy metals and SO 2 simultaneously. This will be favorable to academic and practical applications in the future.

Dry reforming of methane (DRM) can convert greenhouse gases (CO2 and CH4) into value-added syngas (CO and H2), which is one of the promising approaches to achieve carbon neutrality. Designing coking resistant catalysts is still a challenge for an efficient DRM reaction. Here, we developed an efficient binary Mo–Ni catalyst through elucidating the promotional role of Mo in boosting the coking resistance of Ni-based catalysts during the DRM. Mo-modified ZSM-5 served as the “smart support”, which provided the dynamic variation between MoO x and MoO x C y , enabling efficient carbon removal during the DRM reaction. Furthermore, the introduction of Mo maintained more active Ni0 species and enhanced the activity. A more effective pathway via a formate intermediate driven by the Mo-modified Ni/ZSM-5 further suppressed coking during DRM. This work discovered that both activity and coking resistance of traditional Ni catalysts can be simultaneously improved due to the addition of Mo through restraining Ni oxidation and a unique MoO x ↔ MoC x O y redox cycle.

Reducing the poisoning effect of alkali and heavy metals over ammonia selective catalytic reduction (NH3-SCR) catalysts is still an intractable issue, as the presence of K and Pb in fly ash greatly hampers their catalytic activity by impairing the acidity and affecting the redox properties of the catalysts, leading to the reduction in the lifetime of SCR catalysts. To address this issue, we propose a novel self-protected antipoisoning mechanism by designing SO4 2–/TiO2 superacid supported CeO2–SnO2 catalysts. Owing to the synergistic effect between CeO2 and SnO2 and the strong acidity originating from the SO4 2–/TiO2 superacid, the catalysts show superior catalytic activity over a wide temperature range (240–510 °C). Moreover, when K or/and Pb are deposited on SO4 2–/TiO2 catalysts, the bond effect between SO4 2– and Ti–O would be broken so that the sulfate in the bulk of SO4 2–/TiO2 superacid support would be induced to migrate to the surface to bond with K and Pb, thus prohibiting poisons from attacking the Ce–Sn active sites, and significantly boosting the resistance. Hopefully, this novel self-protection mechanism derived from the migration of sulfate in the SO4 2–/TiO2 superacid to resist alkali and heavy metals provides a new avenue for designing novel catalysts with outstanding resistance to alkali and heavy metals.

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The reaction mechanisms of the partial oxidation of methane to methanol over FeO/graphene are unraveled using an advanced DFT approach.

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