The adsorption of molecules usually increases capacity and/or strength with the doping of surfaces with transition metals; furthermore, carbon nanostructures, i.e., graphene, carbon nanotubes, fullerenes, graphdiyne, etc., have a large specific area for gas adsorption. This review focuses on the reports (experimental or theoretical) of systems using these structures decorated with transition metals for mainly pollutant molecules’ adsorption. Furthermore, we aim to present the expanding application of nanomaterials on environmental problems, mainly over the last 10 years. We found a wide range of pollutant molecules investigated for adsorption in carbon nanostructures, including greenhouse gases, anticancer drugs, and chemical warfare agents, among many more.

Using DFT simulations, we studied the interaction of a semifullerene C₃₀ and a defected graphene layer. We obtained the C₃₀ chemisorbs on the surface. We also found the adsorbed C₃₀ chemisorbs, Li, Ti, or Pt, on its concave part. Thus, the resulting system (C₃₀-graphene) is a graphene layer decorated with a metal-doped C₃₀. The adsorption of the molecules depends on the shape of the base of the semifullerene and the dopant metal. The CO molecule adsorbed without dissociation in all cases. When the bottom is a pentagon, the adsorption occurs only with Ti as the dopant. It also adsorbs for a hexagon as the bottom with Pt as the dopant. The carbon dioxide molecule adsorbs in the two cases of base shape but only when lithium is the dopant. The adsorption occurs without dissociation. The ozone molecule adsorbs on both surfaces. When Ti or Pt are dopants, we found that the O₃ molecule always dissociates into an oxygen molecule and an oxygen atom. When Li is the dopant, the O₃ molecule adsorbs without dissociation. Methane did not adsorb in any case. Calculating the recovery time at 300 K, we found that the system may be a sensor in several instances.

Using structural relaxation calculations and first-principles molecular dynamics (FPMD), we performed numerical simulations to explore the interaction of a 2D MoS₂ surface and a platinum atom, calculating the optical properties of the resulting material. We explored three initial positions for the interaction of the Pt atom and the pristine MoS₂ surface, plus another position between Pt and the MoS₂ surface with a sulfur vacancy V_S. The surface absorbed the Pt atom in all cases considered, with absorption energies ranging from −2.77 eV to −5.83 eV. We calculated the optical properties and band structure of the two cases with the largest absorption energies (−3.45 eV and −5.83 eV). The pristine MoS₂ is a semiconductor with a gap of around 1.80 eV. With the adsorption of the Pt atom (the −3.45 eV case), the material reduces its band gap to 0.95 eV. Additionally, the optical absorption in the visible range is greatly increased. The energy band structure of the 2D MoS₂ with a sulfur vacancy V_S shows a band gap of 0.74 eV, with consequent changes in its optical properties. After the adsorption of Pt atoms in the V_S vacancy, the material has a band gap of 1.06 eV. In this case, the optical absorption in the visible range increases by about eight times. The reflectivity in the infrared range gets roughly doubled for both situations of the Pt-absorbed atom considered. Finally, we performed two FPMD runs at 300 K to test the stability of the cases with the lowest and highest absorption energies observed, confirming the qualitative results obtained with the structural relaxations.

Using first-principles molecular dynamics (FPMD), we performed numerical simulations at 300 K to explore the interaction of a 2D MoS2 surface and a platinum atom, calculating the optical properties of the resulting material. The pristine MoS2 is a semiconductor with a gap of around 1.8 eV. The Pt atom is chemisorbed by the surface with an adsorption energy of −1.718 eV. With the adsorption of the Pt atom, the material remains a semiconductor, and its energy band gap reduces to 1.04 eV. But changes in the material's energy band structure imply substantial changes in its optical properties. The energy band structure of the 2D MoS2 with a sulfur vacancy VS shows that the material becomes a conductor, and there are significant changes in its optical properties. We also found that the Pt atom chemisorbs in a sulfur vacancy of the material, with an adsorption energy of −4.1164 eV. After the adsorption of Pt atoms in the sulfur vacancy, the material becomes a semiconductor with a band gap of 1.06 eV, and the changes in the optical absorption and reflectivity are significant.

Utilizando la teoría del funcional de la densidad (DFT) y el formalismo del pseudopotencial, se realizaron cálculos computacionales ab initio para estudiar un sistema formado por un semifullereno (C₃₀) y una hoja de grafeno (5,5) con vacancias, así como también, predecir las propiedades catalíticas en la adsorción de moléculas contaminantes: O, CO₂, CH₄ y O₃ cuando el sistema es decorado con diferentes metales (Li, Ti y Pt). Se consideraron dos configuraciones para el sistema, el semifullereno interactuando con el grafeno con una base hexagonal y la otra con base pentagonal. Encontramos que en las dos configuraciones propuestas el semifullereno se adsorbe a la hoja de grafeno con vacancias. Además, en ambas configuraciones: grafeno+C₃₀penta y grafeno+C₃₀hexa, el semifullereno se pudo decorar con un átomo de los metales de Li, Ti y Pt. Así, obtuvimos diferentes superficies, las cuales están formadas por una hoja de grafeno y semifullereno decorado con un metal (grafeno+C₃₀M), el metal funciona como catalizador en la adsorción de las diferentes moléculas contaminantes. Encontramos que la adsorción de las moléculas depende de la forma de la base del semifullereno y del metal. Tenemos que el CO se adsorbe cuando la superficie con base pentagonal esta dopada con Ti y cuando la superficie base hexagonal esta dopada con Pt. En ambos casos el CO se adsorbe sin disociación. El CO₂ se adsorbe en ambas superficies cuando están dopadas con Li, la adsorción también ocurre sin disociación de la molécula. El O₃ se adsorbe en todas las configuraciones de la superficie. Se observa que cuando la superficie está dopada con Pt ó Ti, el O₃ se disocia en un átomo de O y una molécula de O₂. El CH₄ no se adsorbe en ningún caso.