Detecting and monitoring air-polluting gases such as carbon monoxide (CO), nitrogen oxides (NO_x), and sulfur oxides (SO_x) are critical, as these gases are toxic and harm the ecosystem and the human health. Therefore, it is necessary to design high-performance gas sensors for toxic gas detection. In this sense, graphene-based materials are promising for use as toxic gas sensors. In addition to experimental investigations, first-principle methods have enabled graphene-based sensor design to progress by leaps and bounds. This review presents a detailed analysis of graphene-based toxic gas sensors by using first-principle methods. The modifications made to graphene, such as decorated, defective, and doped to improve the detection of NO_x, SO_x, and CO toxic gases are revised and analyzed. In general, graphene decorated with transition metals, defective graphene, and doped graphene have a higher sensibility toward the toxic gases than pristine graphene. This review shows the relevance of using first-principle studies for the design of novel and efficient toxic gas sensors. The theoretical results obtained to date can greatly help experimental groups to design novel and efficient graphene-based toxic gas sensors.

A density functional theory (DFT) investigation was conducted to study the O₂ and CO₂ adsorption on very small Pd_3−nNi_n (n = 0–2) clusters supported on N-doped graphene quantum dots (N-GQDs). The study was carried out in two stages. First, the interaction between Pd_3−nNi_n (n = 0–2) clusters and N-GQDs was analyzed. Subsequently, the adsorption behavior of O₂ and CO₂ molecules on the supported clusters was examined. The calculated interaction energies (E_int) of Pd_3−nNi_n (n = 0–2) clusters on N-GQDs were found to be higher than those on pristine graphene, indicating enhanced cluster stability on N-GQDs. Furthermore, the adsorption energies (E_ads) of the O₂ molecule on the Pd₃ and Pd₂Ni clusters deposited on N-GQDs were similar. Meanwhile, the PdNi₂ cluster deposited on N-GQDs exhibited the highest E_ads (−1.740). The E_ads of CO₂ on Pd_3−nNi_n (n = 0–2) clusters embedded in N-GQDs were observed to be close to or exceed 1 eV. Upon adsorption of O₂ and CO₂ on the Pd_3−nNi_n (n = 0–2) clusters supported on N-GQDs, an elongation of the O–O and C–O bond lengths was observed, respectively. This structural change may facilitate the dissociation of these molecules on the supported clusters.

The transformation of forest landscapes is driven by complex socioecological dynamics. This research analyzes territorial transitions in the Zapotec indigenous community of San Pedro el Alto, Oaxaca, Mexico, from 1997 to 2021, linking vegetation cover changes with the consolidation of its community forest enterprise. Through a mixed methods design, we integrated a multitemporal geospatial analysis of cartographic series with systematic archival research and qualitative triangulation based on semi-structured interviews with key community stakeholders. Our results reveal a strong temporal correspondence, indicating that forest canopy alterations align with institutional milestones and silvicultural cycles rather than representing arbitrary degradation. The evidence indicates that intense forest disturbance and anthropic transitions, such as agricultural expansion, correspond with industrial operational crises, functioning as temporary, community-regulated social buffering mechanisms to secure livelihoods. Under the theoretical principles of the commons and New Institutional Economics, the forest functions as a highly resilient socioecological system where local governance and landscape modifications respond adaptively to sustain collective wellbeing. These findings highlight the value of combining spatial data with qualitative verification, proving that recognizing collective self-governance can inform contemporary territorial planning models to support biocultural heritage conservation.