C60 Surface Research Articles

Adsorption of molecular hydrogen (H2) on a fullerene (C60) surface: insights from density functional theory and molecular dynamics simulation.

Understanding the adsorption behavior of molecular hydrogen (H2) on solid surfaces is essential for a variety of technological applications, including hydrogen storage and catalysis. We examined the adsorption of H2 (∼2800 configurations) molecules on the surface of fullerene (C60) using a combined approach of density functional theory (DFT) and molecular dynamics (MD) simulations with an improved Lennard-Jones (ILJ) potential force field. First, we determined the adsorption energies and geometries of H2 on the C60 surface using DFT calculations. Calculations of the electronic structure help elucidate underlying mechanisms administrating the adsorption process by revealing how H2 molecules interact with the C60 surface. In addition, molecular dynamics simulations were performed to examine the dynamic behavior of H2 molecules on the C60 surface. We accurately depicted the intermolecular interactions between H2 and C60, as well as the collective behavior of adsorbed H2 molecules, using an ILJ potential force field. Our findings indicate that H2 molecules exhibit robust physisorption on the C60 surface, forming stable adsorption structures with favorable adsorption energies. Calculated adsorption energies and binding sites are useful for designing efficient hydrogen storage materials and comprehending the nature of hydrogen's interactions with carbon-based nanostructures. This research provides a comprehensive understanding of H2 adsorption on the C60 surface by combining the theoretical framework of DFT calculations with the dynamical perspective of MD simulations. The outcomes of the present research provide new insights into the fields of hydrogen storage and carbon-based nanomaterials, facilitating the development of efficient hydrogen storage systems and advancing the use of molecular hydrogen in a variety of applications.

Characterization and efficacy of C60 nano-photosensitive drugs in colorectal cancer treatment

BackgroundFullerenes C60 shows great potential for drug transport. C60 generates large amounts of singlet oxygen upon photoexcitation, which has a significant inhibitory effect on tumor cells, so the photosensitive properties of C60 were exploited for photodynamic therapy of tumors by laser irradiation. MethodsIn this study, C60-NH2 was functionalized by introducing amino acids on the surface of C60, coupled with 5-FU to obtain C60 amino acid-derived drugs (C60AF, C60GF, C60LF), and activated photosensitive drugs (C60AFL, C60GFL, C60LFL) were obtained by laser irradiation. The C60 nano-photosensitive drugs were characterized in various ways, and the efficacy and safety of C60 nano-photosensitive drugs were verified by cellular experiments and animal experiments. Bioinformatics methods and cellular experiments were used to confirm the photosensitive drug targets and verify the therapeutic targets with C60AF. ResultsPhotosensitised tumor-targeted drug delivery effectively crosses cell membranes, leads to more apoptotic cell death, and provides higher anti-tumor efficacy and safety in vitro and in vivo colorectal cancer pharmacodynamic assays compared to free 5-FU.C60 photosensitized drug promotes tumor killing by inhibiting the colorectal cancer FLOR1 tumor protein target, with no significant toxic effects on normal organs. ConclusionC60 photosensitized drug delivery systems are expected to improve efficacy and reduce side effects in the future treatment of colorectal cancer. Further and better development and design of drugs and vectors for colorectal cancer therapy.

Tribological performances of MoS2/C60 nanocomposite as lubricating additive in dioctyl sebacate

PurposeThis paper aims to solve the problems molybdenum disulfide (MoS2) nanosheets suffer from inadequate dispersion stability and form a weak lubricating film on the friction surface, which severely limits their application as lubricant additives.Design/methodology/approachMoS2/C60 nanocomposites were prepared by synthesizing molybdenum disulfide (MoS2) nanosheets on the surface of hydrochloric acid-activated fullerenes (C60) by in situ hydrothermal method. The composition, structure and morphology of MoS2/C60 nanocomposites were characterized. Through the high-frequency reciprocating tribology test, its potential as a lubricant additive was evaluated.FindingsMoS2/C60 nanocomposites that were prepared showed good dispersion in dioctyl sebacate (DOS). When 0.5 Wt.% MoS2/C60 was added, the friction reduction performance and wear resistance improved by 54.5% and 62.7%, respectively.Originality/valueMoS2/C60 composite nanoparticles were prepared by in-situ formation of MoS2 nanosheets on the surface of C60 activated by HCl through hydrothermal method and were used as potential lubricating oil additives.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2023-0321/

Pentagon, Hexagon, or Bridge? Identifying the Location of a Single Vanadium Cation on Buckminsterfullerene Surface.

Buckminsterfullerene C60 has received extensive research interest since its discovery. In addition to its interesting intrinsic properties of exceptional stability and electron-accepting ability, the broad chemical tunability by decoration or substitution on the C60-fullerene surface makes it a fascinating molecule. However, to date, there is uncertainty about the binding location of such decorations on the C60 surface, even for a single adsorbed metal atom. In this work, we report the gas-phase synthesis of the C60V+ complex and its in situ characterization by mass spectrometry and infrared spectroscopy with the help of quantum chemical calculations and molecular dynamics simulations. We identify the most probable binding position of a vanadium cation on C60 above a pentagon center in an η5-fashion, demonstrate a high thermal stability for this complex, and explore the bonding nature between C60 and the vanadium cation, revealing that large orbital and electrostatic interactions lie at the origin of the stability of the η5-C60V+ complex.

(Digital Presentation) Wettability of Carbon Nanostructures – Hydrophobic or Hydrophilic?

Nanocarbon nanostructures have significant potential to be applied in: filtration[1], energy storying[2], thermogenerators[3], electronics[4], and part of composite materials due to their enormous properties[2]. They characterized magnificent electrical, thermal, and mechanical properties. Many people think their surface nature is hydrophobic. However, more and more scientific publications present the opposite statement about carbon nanotubes and graphene[5-7]. The reason for hydrophobicity is undefined hydrocarbons, which are adsorbed on the nanocarbon surface. The surface character is a crucial parameter for such applications as: electrode materials for storage energy and integration degree between a part of composites.The surface of fullerene C60, high quality (ID/IG = 0.01) single-walled carbon nanotubes (SWCNTs), single-layer graphene (SLG) deposed on copper foil have been investigated to understand the phenomenon of hydrophobic surface and prove that there are intrinsic hydrophilic. A coating from C60 was deposed on glass by spin coating and free-standing film from SWCNTs by method described in previous work. SLG on Cu was synthesized by CVD method. The water contact angle (WCA) was used to define character of surface. The sample was annealed in atmosphere H2/Ar (C60 and SLG) and air (SWCNTs) to remove surface impurities. WCA was measured after/before annealing. Initial C60 and SWCNTs have hydrophobic (WCA >90), SLG has slightly hydrophilic (about 80 ºC). After annealing the surface, all of them have a strongly hydrophilic character, which was even superhydrophilic for C60 and SWCNTs. The nanomaterials were characterized after/before annealing by many techniques such as: Raman spectroscopy, X-ray photoelectron spectroscopy, Scanning electron microscopy, Atomic force microscopy, and Attenuated total reflectance-Fourier transform infrared spectroscopy. All of them showed that the nanostructures had not been damaged during the surface purification process. Moreover, after a month of exposure to air, the WCA has increased. The samples were again analyzed by the techniques mentioned before and the reason for changing the surface characters was hydrocarbons. To indeficate the them selected groups of organic compound was deposed onto nanocarbon surface and the experimental results manifested that aromatic hydrocarbons are the main reason of hydrophobicity of the surface.

Development and Evaluation of Biotin Functionalized Fullerenes for the Delivery of Irinotecan to Colon Tumors.

Irinotecan is a promising antitumor agent approved by FDA for intravenous use in colon cancer treatment either alone or in combination. It is a topoisomerase inhibitor and by blocking the topoisomerase-I enzyme, it causes DNA damage and results in cell death. However, it lacks selectivity and specificity for tumor cells, resulting in systemic toxicity. Thus, it is essential to reduce its side effects and improve therapeutic efficacy. The study aimed to improve the therapeutic efficacy and minimize the toxic effects of irinotecan by developing a fullerene functionalized biotin drug delivery system and adsorbing irinotecan on the surface of the functionalized fullerene-biotin complex. Fullerene (C60) has been observed as a potential drug delivery agent and the aminefunctionalized C60-NH2 was synthesized by functionalizing ethylenediamine on the surface of C60. The PEI functionalized C60 was further synthesized by polymerization of aziridine on the surface of C60- NH2. Biotin was attached by an amide linkage to C60-PEI and the anti-colon cancer drug irinotecan (IRI) was encapsulated (C60-PEI-Biotin/IRI). The C60-PEI-Biotin/IRI was characterized and evaluated for in vivo anti-colon cancer activity in rats and the results were compared with the parent drug irinotecan. The results showed that C60-PEI-Biotin/IRI conjugate had a controlled release profile according to in vitro HPLC studies. Moreover in vivo anti-tumor studies suggested that the conjugate proved to be less toxic to vital organs and had high efficacy towards tumor cells. Statistical studies confirmed less tumor index and tumor burden in the case of conjugate when compared to irinotecan. It is hypothesized that the conjugate (C60-PEI-Biotin/IRI) could cross the cell membrane easily through overexpressed biotin receptors on the cell surface of colon cancer cells and showed better efficacy and less toxicity in comparison to IRI in the colon cancer rat model.

CH3 CN@open-C60 : An Effective Inner-Space Modification and Isotope Effect Inside a Nano-Sized Flask.

Despite several small molecules being encapsulated inside cage-opened fullerene derivatives, such species have not considerably affected the structures and properties of the outer carbon cages. Herein, we achieved an effective inner-space modification for an open-cage C60 derivative by insertion of a neutral CH3 CN molecule into the cavity. The CH3 CN@open-C60 thus obtained showed an enhanced polarity, thus affording an easy separation from a mixture containing the empty cage by column chromatography on silica gel, without the preparative HPLC that was needed for previous cases. The less negative reduction potentials with respect to those of empty cage reflect the decreased energy level of the LUMO, which is supported by the DFT calculations. NMR spectroscopy, single-crystal X-ray analysis, and theoretical calculations revealed that both the presence of the encapsulated CH3 CN and cage deformation caused by the CH3 CN play an essential role in the change of the electronic properties. Furthermore, the favored binding affinity of deuterated acetonitrile CD3 CN with internal C60 surface is discussed.

Reducing damage of sputtering and improving conductivity of transparent electrodes for efficient semi-transparent perovskite solar cells

Sputtered indium tin oxide (ITO) is widely used as an electrode in semi-transparent and tandem perovskite solar cells. However, damage from sputtering to under layers and the limited conductivity of ITO are still the two main obstacles that hinder further performance improvement of the devices. In this work, the effects and mechanism of sputtering damage and poor conductivity of ITO are investigated based on a traditional perovskite solar cell with bathocuproine (BCP) buffer layer. In order to suppress the sputtering damage, tin oxide (SnO2) is deposited on C60 to replace the BCP buffer layer. However, it is found that the deposition of SnO2 on the non-reactive C60 by atomic layer deposition will result in island growth of SnO2 film, which is the key reason for large dark current in solar cells. Fortunately, the phenomenon is inhibited by decorating C60 surface with WO3 thin film. In order to improve the conductivity of the transparent electrode, an ITO/Au/ITO multilayer architecture is designed. The fill factor (FF) and power conversion efficiency (PCE) of the semi-transparent solar cells (ST-PSCs) with the modified buffer layer and electrodes reached 76.4% and 17.62%, respectively, showing an improvement of FF and PCE when compared to the device with BCP buffer layer and ITO electrode. It is revealed that the optimization also increases the short circuit current of the solar cells. These results provide new strategies for damage reduction of sputtering and performance improvement of ST-PSCs.

Density functional theory (DFT) computation of pristine and metal-doped MC59 (M = Au, Hf, Hg, Ir) fullerenes as nitrosourea drug delivery systems

In recent times, C60 fullerene and its derivatives have drawn increasing attention in nanomedicine due to their bioavailability and low toxicity. Herein, we investigated the interactions of nitrosourea (NU) drug with pristine and metal-doped MC59 (M = Au, Hf, Hg, Ir) at the M06–2X/gen/LanL2DZ/def2-SVP level of theory. The structural, adsorption energy, charge transfer, electronic, QTAIM, and NCI analyses were investigated based on the density functional theory (DFT). In contrast to physisorption of NU drug on the pristine C60 surface, the metal-doped NU@MC59 complexes have stronger interactions and are chemically adsorbed on the metal-doped fullerene surfaces, with NU@HfC59 having the strongest interaction. Similarly, metal-doping altered global hardness and energy gap values such that reactivity and sensitivity increased for NU@HfC59, NU@HgC59, and NU@IrC59. Meanwhile, the reactivity and sensitivity decreased for NU@AuC59. Among all the complexes, NU@HfC59 exhibited the highest electrical conductivity and sensitivity due to its least HOMO-LUMO energy gap value. The QTAIM and NCI analyses indicated that the complexes are formed predominantly via non-covalent interactions. The results suggest that metal doping enhanced the sensitivity and conductivity of pristine C60. With moderate adsorption energy and low recovery time, especially for HfC59 and IrC59 fullerenes, this indicates that the metal-doped fullerenes are promising nitrosourea drug delivery candidates in nanomedicine.

The quest of the most stable structure of a carboxyfullerene and its drug delivery limits: A DFT and QTAIM approach

Carboxyfullerenes have been widely used for medicinal applications. These classes of materials are known for their promising properties making them suitable for biological implementations. However, theoretical studies for the structural and electronic properties of these versatile carboxyl group attached nanocages seem rare. The definition of interaction points appears to require further enhancement. 5-Fluorouracil drug molecule is considered as the backbone of the most of chemotherapy regimens. Therefore, it deserves special attention. In this work, it was found that the interaction of carboxyl group occurs via adjacent carbon atoms on the hexagon of the surface of C60 and carboxyfullerenes might be suitable candidates for 5-Fluorouracil showing partially covalent interactions for possible drug delivery applications.

Synthesis of Ultrafine Platinum Nanocatalysts by Ice‐photochemical Method and Their Application in Catalytic Degradation of 4‐nitrophenol

AbstractHere, uniformly dispersed ultrafine platinum nanocatalysts (Pt/C60) were synthesized on C60 by ice‐photochemical method using potassium chloroplatinate (K2[PtCl4]) as platinum source under the condition of low temperature, no stabilizer and reducing agent. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), X‐ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM) were used to study the composition and morphology of Pt/C60 catalyst. It was confirmed that Pt Ultra‐small Particles (Pt UPs) was loaded on C60 surface with high dispersion. The average particle sizes of the three samples obtained under different reaction conditions were 1.41±0.1 nm, 1.54±0.4 nm and 1.73±0.3 nm, respectively. The results show that the light‐induced effect and the ice lattice domain limiting effect in the frozen state effectively control the formation and growth of platinum clusters in the process of Pt2+ reduction to Pt0. The rate constants of the three samples were 0.89 min−1, 0.31 min−1, 0.19 min−1, respectively, showing high catalytic activity in the study of the catalytic performance of Pt/C60 degradation of 4‐nitrophenol (4‐NP) by Ultraviolet‐visible spectroscopy (UV‐Vis). This method provides a meaningful attempt for the study of green chemical synthesis method of platinum metal catalysts.

A robust computational investigation on C60 fullerene nanostructure as a novel sensor to detect SCN−

This study explored on the adsorption properties and electronic structure of SCN− via density functional theory analysis on the exterior surfaces of C60 and CNTs using B3LYP functional and 6-31G** standard basis set. Then adsorption of SCN− through nitrogen atom on the C60 fullerene is electrostatic (−48.02 kJ mol−1) in comparison with the C59Al fullerene that shows covalently attached to fullerene surface (−389.10 kJ mol−1). Our calculations demonstrate that the SCN− adsorption on the pristine and Al-doped single-walled CNTs are −173.13 and −334.43 kJ mol−1, indicating that the SCN− can be chemically bonded on the surface of Al-doped CNTs. Moreover, the adsorption of SCN− on the C60 surface is weaker in comparison with C59B, C59Al, and C59Ga systems but its electronic sensitivity improved in comparison with those of C59B, C59Al, and C59Ga fullerenes. The evaluation of adsorption energy, energy gap, and dipole moment demonstrates that the pure fullerene can be exploited in the design practice as an SCN− sensor and C59Al can be used for SCN− removal applications.

Paracetamol adsorption on C60 fullerene and its derivatives: In silico insights

Fullerene-C60 and its heteroatom decorated forms have been widely investigated as drug delivery vehicles and for sensor applications. Further, in the literature carboxylated or carboxylic derivatives of fullerenes have found a special place for biological applications due to their promising water-soluble properties. In the scope of this study, we examined the interaction between paracetamol (acetaminophen) which is a widely prescribed drug to manage acute and chronic pain conditions and C60, silicon doped fullerene (SiC59) and (1,2-methanofullerene C60)-61-carboxylic acid (C60-CH-COOH) using density functional theory calculations. Stability evaluations, electronic and structural properties were carried out by analyzing binding energies, frontier molecular orbitals and natural bond orbitals. It was found that silicon doping on the surface of C60 enhanced the adsorption strength of paracetamol and SiC59 is quite sensitive to the presence of paracetamol drug molecule.

Dissociation mechanism of a C60-Li+ complex by microscopic hydration: density functional theory study

The hydration structure and electronic state of Li+ doped complexes on the surface of C60 were investigated by density functional theory calculations. This system is a simple model for the solvation of Li+ at the anode of a lithium-ion battery. C60 and Li+ bind at approximately 35 kcal mol−1. The new band of C60 formed the lowest excited state, 0.1 eV smaller after interaction with Li+. The water molecule preferentially interacted with the Li portion of the C60-Li+ complex, and a micro-hydration structure was formed around Li+. When four or more water molecules were added to the system, Li+ was removed from the C60 surface by the water molecules, and a hydration shell was formed around both Li+ and C60 (separate hydration). The electronic interaction between C60 and Li+ was completely disrupted by the formation of a microscopic-hydrated shell. Herein, the mechanism is discussed based on the theoretical results.

Activation of CO2 on the Surfaces of Bare, Ti-Adsorbed and Ti-Doped C60

There is a growing interest in finding a suitable catalyst for the adsorption and activation of CO2 molecules to minimize the effect of global warming. In this study, density functional theory-based simulations are employed to examine the adsorption and activation of a CO2 molecule on the pure, Ti-supported and Ti-doped surfaces of C60. The adsorption on the pure surface is very week. Adsorption becomes significant on the Ti-supported C60 surface together with significant activation. Such strong adsorption is evidenced by the significant charge transfer between Ti and C60. The Ti-doped C60 surface adsorbs weakly, but the activation is not significant.

Synergic fabrication of multifunctional liposomes nanocomposites for improved radiofrequency ablation combination for liver metastasis cancer therapy

The field of biomedical research has recently been interested in nanoplatforms with various functionalities, such as cancer drug carriers and MRI and optical imaging, as well as thermal treatment, among other things. As a result of the present investigation, a unique multifunctional liposome (MFL) was established in this investigation. Using radiofrequency-induced imaging and drug release based on magnetic field impact, a dual drug delivery targeted with tumor multi-mechanism treatment was made more effective. The C60 (fullerene) surface was coated with iron nanocomposites to establish the proposed nanosystems, and PEGylation was used (Fe3O4-C60-PEG2000). For fullerene radiofrequency-triggered drug release, thermosensitive DPPC liposomes with folate-DSPE-PEG2000 enveloped the binary nanosystems and doxorubicin (DOX). The in vitro cytotoxicity of the nanocomposites was confirmed by the liver metastasis in HT-29 colon cancer cells using radiofrequency. The flow cytometry analysis confirmed the apoptosis cell death mechanism. The thermal treatment combined chemotherapeutic MFL nano framework transformed radiofrequency radiation from thermoresponsive liposomes, which was noticed both in vivo and in vitro. Due to their superior active tumor targeting and magnetic targeting characteristics, the MFL could also selectively destroy cancerous liver cells in highly co-localized targets.

Surface morphology and dispersion interaction induced anomalous dynamics of solvation water of a hydrophobic fullerene molecule

Knowledge of accurate structural and dynamical features of the surrounding water of a C60 molecule is essential for the proposed uses of C60 in a wide variety of applications viz., in inhibiting HIV protease, DNA cleaving, macromolecular binding and drug delivery. Using molecular dynamics simulations, the present study demonstrates that the solute-water dispersion interaction induces anomalous bulk density dependence of dynamics of solvation water of the C60. In order to elucidate the origin of such behaviour, the analyses of the simulation trajectories are performed and it reveals the presence of two dynamically different types of water molecules: one (designated as Type 1 here), which has no radially outward movements (with respect to C60) throughout the simulation time and performs “bouncing ball” movements on the C60 surface by hopping from one face to another and the other one (Type 2) is fast and goes in and out of the solvation shell frequently. The anomalous dynamics is a consequence of the variable presence of such dynamically heterogeneous water molecules as a function of bulk density, and it, in turn, arises due to the interplay between two opposing effects emanating from the free volume (which depends on bulk density) and the inhomogeneous energy surface of the C60 arising due to icosahedral arrangement of carbon atoms on the surface and attractive solute-water dispersion interaction. It is to emphasize that model C60 with no attractive dispersion interaction does not show any anomalous dynamics.

Strategy for improving the wear-resistance properties of detonation sprayed Fe-based amorphous coatings by cryogenic cycling treatment

Abstract Fe-based amorphous coating is deposited on invar steel substrates using detonation spray and then through the cryogenic cycling (CCT) treatment from 0 to 60 cycles with the interval 10 cycles. Effects of CCT on microstructure, thermal properties, mechanical and tribological properties were investigated. It was found that, all the coated samples with CCT are still well bonded with the invar steel substrate, except for the surface of C60 appears local cracks. Moreover, it also found that although CCT did not significantly change the phase structure of the amorphous coating, CCT promoted the rejuvenation behavior in the amorphous coating, which also led to the heterogeneity of the internal structure. Attributed to this heterogeneity, it promotes the generation of a large amount of free volume in the amorphous coating, which results in a significant change in the toughness and resistance to crack propagation of the amorphous coating. And after 50 CCT cycles, the amorphous coating has undergone an obvious ductile-brittle transition, which has the highest fracture toughness KIC and plastic work Wp value. The COF and wear rate of coatings increased initially, then followed by a decrease, but then again increased with the increase of CCT cycles. The 50-cycles coatings exhibited the lowest COF (0.60) and wear rate (0.56 × 10−5 mm3N−1 m−1). The wear mechanism of all the samples is mainly delamination wear with oxidative wear, but the degree of delamination wear is obviously different, showing a trend corresponding to the tribological behavior of the amorphous coating. Therefore, the CCT method could be an effectively strategy to ameliorate the toughness and then enhance the wear performance of the Fe-based amorphous coating.

Adsorption of cyanogen halides (X-CN; X = F, Cl and Br) on pristine and Fe, Mn doped C60: A highly potential gas sensor

Reliable monitoring of toxic and pollutant gases is a prime concern of the technological and scientific communities, simulated by the terrible environmental pollution crisis. Herein, we systematically investigated the gas (X-CN; X = F, Cl, Br) sensing mechanism of pristine, transition metal (Fe and Mn) doped fullerene C60 using first-principles calculations. The pure C60 surface show quite weak adsorption behavior towards X-CN gas molecules that gives rise to physisorption in these complexes, while chemisorption is observed for the Fe, Mn doped C60/X-CN configurations. Moreover, the prominent adsorption strength, moderate charge transfer and appreciable electronic conductivity demonstrates high sensitivity of metal doped C60 cage towards cyanogen halide gas molecules. The simulated electronic band structure and optical absorption spectra using HSE06 hybrid functional show strong variations after the adsorption of X-CN gases, revealing the potential capability of metal doped C60 as reliable gas sensor. Especially, the band gaps of Fe, Mn doped C60/X-CN complexes were reduced from that of pure counterpart, representing a strong signal for the detection of cyanogen halide gases. Further, the sensitivity of X-CN gases were correlated with π electron occupancy of the host materials. As we extol the remarkable sensitivity of fullerene C60, we believe that these findings may capture widespread attention towards wearable chemical sensors for future applications.

Hydrogen Adsorption on Ru-Encapsulated, -Doped and -Supported Surfaces of C60

Hydrogen is considered as one of the promising clean energy sources for future applications including transportation. Nevertheless, the development of materials for its storage is challenging particularly as a fuel in vehicular transport. In the present study, density functional theory simulations for hydrogen adsorption on the surfaces of pristine, Ru-encapsulated, -doped and -supported C60 are reported. The results show that adsorption on the pristine C60 is exoergic and there is an enhancement in the adsorption upon encapsulation of a single Ru atom. The Ru-doped surface also adsorbs H2 more strongly than the pristine surface, but its efficacy is slightly less than the Ru-encapsulated surface. The strongest adsorption is calculated for the C60 surface supported with Ru.