CH4 Molecules Research Articles

Theoretical design of an effective He separation membrane based on nanoporous C9N4 monolayer

Motivated by the design of high-performance membranes for helium (He) separation, the He separation properties of the C9N4 membrane was systemically investigated via the combination of first-principles methods and molecular dynamics simulations. The gases (He, Ne, Ar, N2, O2, CO, CO2, and CH4) are all weakly physisorbed on the C9N4 membrane. The diffusion energy barrier for He is just 0.07 eV, but that of Ne, Ar, N2, O2, CO, CO2, and CH4 molecules is 0.14, 0.87, 0.55, 0.27, 0.44, 0.65, and 1.45 eV, respectively. The C9N4 monolayer exhibits ultra-high He selectivity relative to other gases in a wide temperature range. The He permeance of the C9N4 membrane is 1.5 × 10−3 mol·s−1·m−2·Pa−1 at room temperature, which is much higher than the acceptance value of industrial production standard. In addition, MD simulations reveal that the He separation process should be operated below 500 K so that can obtain the ultra-highly purified He gas via the C9N4 membrane. It thus shows that the C9N4 membrane has excellently high selectivity and permeance for He separation, and it is hopefully inspired experimentalists to realize the promising He separation membrane based on the C9N4 monolayer.

Exploration of Pt-doped Janus WSSe monolayer as a typical gas sensor for condition assessment in XLPE cables

To evaluate the operation status of the XLPE cables in the power system, we purpose Pt-doped WSSe (Pt-WSSe) monolayer as a novel gas sensor for detections of the XPLE typical gases under the insulation defects. The adsorption and sensing mechanisms of the Pt-WSSe monolayer upon five typical gases, namely CO, C2H6, C2H4O, C4H6O and C8H8O are uncovered in this work, using the first-principles theory. We find that the for Pt-doping on Se-surface of the Janus WSSe monolayer is more energy-favorable and chemical stable, with the formation energy of −0.29 eV, and the bandgap of the identified Pt-WSSe monolayer is obtained as 1.34 eV. Besides, the Pt-WSSe monolayer performs chemisorption upon CO, C2H4O, C4H6O and C8H8O molecules, while performs physisorption upon C2H6 molecule, and the adsorption energies are calculated as −1.88, −0.97, −0.77, −1.55 and −1.62 eV, respectively. These gas interactions deform the electronic property of the Pt-WSSe monolayer, causing the remarkably change in its bandgap, and the caused sensing responses indicate the strong potential to be a potential resistance-type gas sensor upon CO, C2H4O and C4H6O detections, with the sensing response of −93.4 %, −97.5 % and −99.7 %, respectively. Moreover, the limited change in the work function (WF) of Pt-WSSe monolayer suggests its unsuitability to be a WF-type gas sensor for detection of XLPE typical gas species. All these findings not only illustrate the Pt-doping behavior on the physicochemical properties of Janus WSSe monolayer, but also uncover the gas sensing mechanism of metal-doped Janus TMDs for explorations of novel sensing materials.

Carbon dioxide and methane capture in metal-organic framework MIL-101(Cr) at high pressure

Due to the presence of high CO2 amounts in the natural gas stream, a variety of efforts have been employed in the search for more efficient materials for the separation of gaseous mixtures such as CO2/CH4. In this article, a metal-organic framework (MIL-101) was synthesized and characterized, which showed a wide surface area (2924.8 m2 g−1 per BET) and a high volume of pores (1.32 cm³ g−1 per DFT). This structure was used to study the adsorption capacity of CO2 and CH4 within systems pressurized up to 100 bar - where a high adsorption capacity of CO2 was evidenced under 45 °C. Moreover, it was possible to distinguish between the high selectivity of this structure for CO2 molecules and its low capture of CH4 molecules. Also, the high stability of MIL-101 was noted after 6 cycles of adsorption and desorption of CO2 under 50 bar and 45 °C, thereby maintaining its adsorption capacity and crystallinity. Finally, isotherms of CO2 adsorption were successfully adjusted with the use of the Toth model.

Research on nonsteady-state adsorption and regulation towards stabler adsorption for benzene over single-wall carbon materials.

With the intention of separating benzene (C6H6) from indoor polluted air and collecting it in a cleaner way, it is promising of getting C6H6 adsorbed on activated carbon materials with outstanding physicochemical properties. In this study, how C6H6 is adsorbed over single-wall carbon materials and relevant adsorption processes are enhanced is thoroughly investigated via density functional theory (DFT). Especially, distinction between partial and whole effects of adsorbents on C6H6 adsorption, features of electron distribution across section of adsorption forms, and regulation mechanism of nonsteady-state adsorption for C6H6 are key points. According to calculation results, C6H6 molecules could be captured by pure single-wall carbon nanotube (CNT) through repulsive forces (quantified as 103.42 kJ/mol) from all quarters, which makes it stay in nonsteady-state adsorption forms and easily run into free state. Therefore, when external temperature increases from 0 to 300 K, molecular movement will be intense enough to help C6H6 break into another random positions instead of statistically remaining immobile. As for this problem, single-wall CNTs are modified through making defects and replacing some C atoms with N atoms, respectively. In this way, surficial electron distribution of modified adsorbents is regulated to tremendously cut down repulsive forces (quantified as 50.30 kJ/mol) and reverse nonsteady-state adsorption into near-equilibrium quasi-steady-state adsorption (single-side attraction near 100 kJ/mol). Therefore, this research would provide useful information for exploiting single-wall carbon materials as effective adsorbents of C6H6 in order to quickly achieve indoor air purification.

Bioinspired Cu(II) Defect Sites in ZIF-8 for Selective Methane Oxidation.

Activating the C-H bonds of alkanes without further oxidation to more thermodynamically stable products, CO and CO2, is a long-sought goal of catalytic chemistry. Inspired by the monocopper active site of methane monooxygenase, we synthesized a Cu-doped ZIF-8 metal-organic framework with 25% Cu and 75% Zn in the nodes and activated it by heating to 200 °C and dosing in a stepwise fashion with O2, methane, and steam. We found that it does oxidize methane to methanol and formaldehyde. The catalysis persists through at least five cycles, and beyond the third cycle, the selectivity improves to the extent that no CO2 can be detected. Experimental characterization and analysis were carried out by PXRD, DRUV-vis, SEM, and XAS (XANES and EXAFS). The reaction is postulated to proceed at open-coordination copper sites generated by defects, and the mechanism of methanol production was explicated by density functional calculations with the revMO6-L exchange-correlation functional. The calculations reveal a catalytic cycle of oxygen-activated CuI involving the conversion of two molecules of CH4 to two molecules of CH3OH by a sequence of hydrogen atom transfer reactions and rebound steps. For most steps in the cycle, the reaction is more favored by singlet species than by triplets.

Fluorinated metal-organic framework for methane purification from a ternary CH4/C2H6/C3H8 mixture

Herein we present a fluorinated metal-organic framework of {(Me2NH2)[Ni3(μ3-OH)(CF3-BPDC-CF3)3(tpt)]}n (1) constructed from 2,2'-bis(trifluoromethyl)biphenyl-4,4'-dicarboxylic (CF3-BPDC-CF32‒) and 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpt) ligands, which is developed for separating propane (C3H8) and ethane (C2H6) from natural gas. Compound 1 preferentially adsorbs C3H8 and C2H6 over CH4 demonstrated by gas adsorption experiments. The presence of trifluoromethyl groups on the biphenyl-4,4'-dicarboxylic ligands facilitates the highly polarized micropore environments for compound 1, thus providing suitable micorpores for capturing the C3H8 and C2H6 molecules with larger polarizabilities and sizes compared to CH4 molecule. The dynamic mixture breakthrough experiments showed that compound 1 can separate C3H8 and C2H6 from the ternary CH4/C2H6/C3H8 mixtures efficiently, endowing compound 1 with excellent methane purification ability.

Importance of resonance-stabilized radicals in soot formation mechanism of diphenyl ether pyrolysis

Soot formation during fuel pyrolysis can pose environmental and human health hazards. As a typical coal-related model compound, diphenyl ether (DPE) represents the specific structures in coal. In this study, soot formation mechanism of DPE pyrolysis was systematically investigated from theoretical principle. The molecular dynamics (MD) simulations show that the variety and number of DPE pyrolysis products increase with the raising temperature. In addition, the higher temperature also promotes the soot formation. Quantum mechanics (QM) calculations indicate that the energy barrier of CO removal from the phenoxy radical is lower than that of the phenyl isomerization reaction, leading to the easier depletion of the phenoxy radical. It is consistent with the result observed from the MD simulation that the phenoxy is consumed more rapidly than phenyl. The main pathways for initial ring formation are the isomerization of polyyne-like chains and the decomposition of DPE molecules which form the ring molecules of C6H5 and C5H5. C2H2 molecule and resonance-stabilized radical (RSR) species like C3H3, C6H5 and C5H5 are precursors for the growth of polycyclic aromatic hydrocarbons (PAHs), which have an important role in the growth process of soot. Subsequently, larger PAHs aggregate with each other to form incipient soot particles which will undergo surface growth and graphitization processes. We hope this work can provide worthy insights into the mechanism of soot formation in DPE and the suppression of carbon soot.

Experimental study of the formation and decomposition of mixed gas hydrates in water-hydrocarbon system

The phase transition of gas hydrate with two or more guests is associated with gas recovery, storage and separation. In this work, the formation and decomposition of binary and ternary gas hydrates containing CH4, C2H6 and C3H8 were investigated experimentally in high-pressure reactors equipped with visual windows. The gas compositions during mixed hydrates formation and decomposition were analyzed to track the occupation of guests in hydrate structures and the release of guests from hydrate cages. It was found that of CH4 was adsorbed in the hydrate cages constructed by C2H6 and C3H8 in the initial stage. In the depressurized decomposition of CH4-C3H8 hydrates and CH4-C2H6-C3H8 hydrates slurry, CH4 and C2H6 molecules were preferentially released from hydrate structures while more C3H8 molecules were able to stay in hydrate phase, which was in accordance with the order of the diameter ratio of guest molecule to hydrate cage. The preservation of CH4-C3H8 hydrates and CH4-C2H6-C3H8 hydrates above 0 ℃ was observed under a low pressure. It was proposed that the reconstitution or reformation of hydrate layer rich of C3H8 may encrust the remaining hydrate particles, preventing hydrate from further quick decomposition. In-situ Raman spectra confirmed the enrichment of C3H8 molecules at the surface of CH4-C3H8 hydrates, which revealed that the metastable hydrate layer rich of C3H8 molecules may act as mass transfer resistance of gas release from hydrate decomposition. Differently, the decompositions of CH4-C2H6 hydrates and C2H6-C3H8 hydrates were uniform as different guests were produced concurrently without preservation. The new insights into mixed hydrates decomposition in this work may provide a new basis for mixed gas production from gas hydrate, and gas storage and separation with hydrate.

Mechanisms of CH4 activation over oxygen-preadsorbed transition metals by ReaxFF and AIMD simulations.

The chemisorbed oxygen usually promotes the CH bond activation over less active metals like IB group metals but has no effect or even an inhibition effect over more active metals like Pd based on the static electronic structure study. However, the understanding in terms of dynamics knowledge is far from complete. In the present work, methane dissociation on the oxygen-preadsorbed transition metals including Au, Cu, Ni, Pt, and Pd is systemically studied by reactive force field (ReaxFF). The ReaxFF simulation results indicate that CH4 molecules mainly undergo the direct dissociation on Ni, Pt, and Pd surfaces, while undergo the oxygen-assisted dissociation on Au and Cu surfaces. Additionally, the ab initio molecular dynamics (AIMD) simulations with the umbrella sampling are employed to study the free-energy changes of CH4 dissociation, and the results further support the CH4 dissociation pathway during the ReaxFF simulations. The present results based on ReaxFF and AIMD will provide a deeper dynamic understanding of the effects of pre-adsorbed oxygen species on the CH bond activation compared to that of static DFT.

Accurate and efficient calculations of Hellmann-Feynman forces for quantum computation.

First-order derivatives of energies with respect to atomic coordinates are widely computed and used in quantum chemistry simulations. The rapidly emerging technology of quantum computing offers a new paradigm for solving relevant quantum chemistry equations. In this work, we have achieved analytical calculations of atomic forces based on the Hellmann-Feynman theorem within the framework of the variational quantum eigensolver. The accuracy of the approach is demonstrated by calculating the atomic forces of H2, LiH, H2O, and NH3 molecules, which are in excellent agreement with values obtained from full configuration interaction calculations. In particular, for systems with degenerate molecular orbitals, the analytical approach has a significant accuracy advantage over finite-difference-based methods and will not involve additional computational effort on a quantum computer. The calculated forces are further used to optimize the geometries of NH3 and CH4 molecules and to perform abinitio molecular dynamics simulations for the umbrella inversion of NH3, demonstrating the feasibility of the approach in practical quantum chemistry simulations.

Active Sites Decorated Nonpolar Pore-Based MOF for One-step Acquisition of C2 H4 and Recovery of C3 H6.

Herein, a 2-fold interpenetrated metal-organic framework (MOF) Zn-BPZ-TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one-step C2 H4 purification from C2 H6 or C3 H6 mixtures as well as recovery of C3 H6 from C2 H6 /C3 H6 /C2 H4 mixtures. The MOF exhibits the favorable C2 H6 and C3 H6 uptakes (>100 cm3 g-1 at 298 K under 100 kPa) as well as selective adsorption of C2 H6 and C3 H6 over C2 H4 . The C3 H6 - and C2 H6 -selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3 H6 or C2 H6 molecules and methyl groups as well as triazine rings in pores. Zn-BPZ-TATB not only can directly generate 323.4 L kg-1 and 15.4 L kg-1 of high-purity (≥99.9 %) C2 H4 from C3 H6 /C2 H4 and C2 H6 /C2 H4 mixtures, but also provide a large high-purity (≥99.5 %) C3 H6 recovery capacity of 60.1 L kg-1 from C3 H6 /C2 H4 mixtures. More importantly, the high-purity C3 H6 (≥99.5 %) and C2 H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg-1 can be simultaneously obtained from C2 H6 /C3 H6 /C2 H4 mixtures through a single adsorption/desorption cycle.

Active Sites Decorated Nonpolar Pore‐Based MOF for One‐step Acquisition of C2H4 and Recovery of C3H6

AbstractHerein, a 2‐fold interpenetrated metal‐organic framework (MOF) Zn‐BPZ‐TATB with accessible N/O active sites in nonpolar pore surfaces was reported for one‐step C2H4 purification from C2H6 or C3H6 mixtures as well as recovery of C3H6 from C2H6/C3H6/C2H4 mixtures. The MOF exhibits the favorable C2H6 and C3H6 uptakes (>100 cm3 g−1 at 298 K under 100 kPa) as well as selective adsorption of C2H6 and C3H6 over C2H4. The C3H6‐ and C2H6‐selective feature were investigated detailedly by experimental tests as well as sorption kinetic studyies. Molecular modelling revealed the multiple interactions between C3H6 or C2H6 molecules and methyl groups as well as triazine rings in pores. Zn‐BPZ‐TATB not only can directly generate 323.4 L kg−1 and 15.4 L kg−1 of high‐purity (≥99.9 %) C2H4 from C3H6/C2H4 and C2H6/C2H4 mixtures, but also provide a large high‐purity (≥99.5 %) C3H6 recovery capacity of 60.1 L kg−1 from C3H6/C2H4 mixtures. More importantly, the high‐purity C3H6 (≥99.5 %) and C2H4 (≥99.9 %) with the productivities of 38.2 and 12.7 L kg−1 can be simultaneously obtained from C2H6/C3H6/C2H4 mixtures through a single adsorption/desorption cycle.

Influences of Evolution of Pore Structures in Tectonic Coal under Acidization on Methane Desorption.

Experiments on corrosion reactions of pulverized coal with monomeric and polymeric (mixed) acid solutions reveal that monomeric acids are listed in a descending order as HF, HCl, and CH3COOH according to their corrosion effects on tectonic coal collected in Faer Coal Mine (Liupanshui City, Guizhou Province, China). In addition, the optimal mixing ratio of mixed acids is 6% HCl + 6% HF + 3% CH3COOH + 2% KCl. The mineral grains filled in pores in coal samples treated with mixed acid solutions are dissolved, so the porosity increases. The volumes of transition pores and mesopores are obviously affected by acidization, and some transition pores are transformed into mesopores and macropores to form dissolved pores. At the same time, inkbottle-shaped pores reduce, while slit pores or open pores increase. The coal samples after acidization show a higher aromatization degree and an increased relative content of oxygen-containing functional groups, with a generally lower hydroxyl content, so the methane (CH4) adsorption capacity of coal declines, which promotes CH4 desorption. The control effect of pore structures after acidization reactions on CH4 desorption was revealed from perspectives of the diffusion coefficient (Kn), adsorption volume (ω), average pore-throat ratio (PT), and average sinuosity (τav). That is, CH4 molecules in tectonic coal after acidization turn from Knudsen diffusion to transitional diffusion, the adsorption volume of CH4 molecules shrinks, the average pore-throat ratio decreases, and the average sinuosity reduces, which promotes CH4 desorption from tectonic coal.

Surface oxygen vacancy-dependent molecular oxygen activation for propane combustion over α-MnO2

Oxygen vacancies (OV), as the sites of molecular oxygen adsorption and activation, play an important role in the catalytic combustion process of volatile organic compounds (VOCs). Revealing the relationship between OV concentration and molecular oxygen activation behavior is of significance to construct the efficient catalysts. Herein, α-MnO2 with different OV concentrations was prepared to investigate the molecular oxygen activation for C3H8 combustion. It is disclosed that the enhanced OV concentration in α-MnO2 induced the reconfiguration of surface metal atoms, resulting in the transformation of oxygen activation configuration from end-on mode to side-on mode. Oxygen molecules in side-on mode possessed more localized electron density and weaker coordination bond strength with surrounding Mn atoms, which were more favorable to adsorb C3H8 molecules and activate C-H bond for the improved combustion performance. This work provides a new understanding to reveal that the increased OV concentration contributes to more efficient VOCs combustion.

Synthesis of ultrafine VN particles by vanadium trioxide reduction–nitridation in a CH4–N2 atmosphere: Mechanistic and experimental study

Owing to its high hardness, favourable stability, and good electrical performance, vanadium nitride (VN) is extensively used as an alloy additive, electrode material, ceramic material, and catalyst. However, the traditional synthesis methods for VN require high temperatures and long soaking times. Herein, ultrafine VN particles were prepared at a lower temperature and shorter soaking time from V2O3 powder in the presence of a CH4–N2 gas mixture. Thermodynamic analyses, ab initio molecular dynamics (AIMD) simulations, and experimental investigations were performed to investigate the mechanisms of this process. Thermodynamic analysis showed that V2O3 reacts with the CH4–N2 gas mixture under atmospheric pressure at a lower temperature to produce VN. The interactions between CH4, V2O3, and N2 at the atomic level were systematically clarified, and the important role of N2 molecules was determined using AIMD simulations. N2 not only reacts with V2O3 to form V–N bonds but also acts as a medium for adsorbed CH4 molecules to decompose and act as a further reducing agent. The experimental results showed that ultrafine VN particles were obtained at a heating temperature of 1173 K, soaking time of 1.5 h, CH4:N2 molar ratio of 1:2, and gas flow rate of 0.9 L/min. The final product was characterised by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The O and N content measured by an O/N analyser is 0.34% and 16.2%, respectively, and the C content by a C/S analyser is 4.87%.

Immobilization of open O-donor sites within a double-walled metal-organic framework for efficient C2H2/CO2 separation

Acetylene is an important industrial material for the production of acetaldehyde, acetic acid, benzene, synthetic rubber, synthetic fiber, etc., and its separation from the gas mixtures of C2H2/CO2 is of great importance but a challenging task due to their similar physical properties and molecular sizes. In this study, taking the advantage of open-donor sites on the pore surface as the nano-traps for C2H2 molecules, a new microporous metal-organic framework (MOF) formulated as {[Co3(OH)2(HCOO)2(CPT)2](NMF)2(MeOH)3(H2O)}n (1, NMF = N-methylformamide) has been prepared by virtue of a bifunctional organic ligand 4-(4H-1,2,4-triazol-4-yl)benzoic acid (HCPT), which showed discriminating sorption performance toward C2H2 (113 cm3/g at 298 K and 1 bar) over CO2 (33 cm3/g) under the same conditions. The different sorption behavior of {[Co3(OH)2(HCOO)2(CPT)2]}n between C2H2 and CO2 results in a high uptake ration (3.4:1) and IAST selectivity (13) at 298 K and 1 bar. Furthermore, the force-field based grand canonical Monte Carlo (GCMC) simulation results demonstrate that the large electronegativity and polarizability of open O donor sites on the pore surface contribute to its high C2H2/CO2 separation performance, leading to its more favorable C2H2 uptakes than CO2.

CoCe composite catalyst for the CH4/CO2 reforming reaction: Synergistic effects between Co and Ce species

The greenhouse gases CH4 and CO2 can be use as feedstock to prepare syngas (CO + H2) by CH4/CO2 reforming reaction, and the syngas can be used to produce high value-added chemicals through Fischer-Tropsch reaction. That is, the CH4/CO2 reforming reaction can provide an effective way to rationally use CO2 and CH4. The CoCe catalysts were prepared by impregnation method and grinding method, respectively, and the physicochemical properties were characterized by H2-TPR, XRD, BET, Quasi in-situ XPS and CO2-TPD. The synergistic effects between Co and Ce species can promote the CH4 and CO2 molecules to be continuously and rapidly activated, so that the CoCe catalysts exhibited good catalytic activity for the CH4/CO2 reforming reaction. The preparation methods can affect the dispersion of the Co species and the thermal stability of the oxygen vacancies on the CoCe catalysts to affect catalytic activity. The impregnation method is conducive to the Co species dissolving into the CeO2 lattice to form oxygen vacancies with high thermal stability, and the Co species on the CeO2 surface were in a highly dispersed state, which can provide more stable catalytic activity centers. Thus, the catalysts prepared by impregnation method displayed superior catalytic performances for CH4/CO2 reforming reaction. And the CH4 and CO2 conversions can reach 43.4% and 29.0% at the reaction temperature of 600 °C, respectively.

Properties and mechanisms of low concentration methane catalytic combustion in porous media supported with transition metal oxides

Low concentration methane (LCM) from coal mining is hardly utilized by combustion or oxidation due to its low concentration and fluctuation. Herein, a porous media catalytic combustion technology was presented to investigate the catalytic combustion properties of LCM in porous media by developing three porous media catalysts (Fe2O3/Al2O3, CuO/Al2O3 and Co3O4/Al2O3) supported with transition metal oxides (Fe2O3, CuO and Co3O4) as active components. While the catalytic combustion mechanism was proposed by density functional theory (DFT) calculations. The results indicated that Fe2O3/Al2O3 exhibited superior high-temperature catalytic activity and thermal stability, which was capable of broadening the limit equivalence ratio of CH4 stationary combustion to 0.46 with the CH4 conversion rate over 98 %. DFT calculations revealed that the Fe atoms on the (001) surface of Fe2O3 crystals were the active center during the catalytic process, causing the adsorption and dissociation of CH4 and O2 molecules. The lattice oxygen of Fe2O3 was engaged in the formation of CO and CO2 and the adsorbed oxygen from O2 molecules dissociation facilitated H2O generation, which heightened the conversion of CH4. This study provides a promising avenue for the high-efficiency and clean utilization of LCM.

A DFT Study of Volatile Organic Compounds Detection on Pristine and Pt-Decorated SnS Monolayers.

Real-time monitoring of volatile organic compounds (VOCs) is crucial for both industrial production and daily life. However, the non-reactive nature of VOCs and their low concentrations pose a significant challenge for developing sensors. In this study, we investigated the adsorption behaviors of typical VOCs (C2H4, C2H6, and C6H6), on pristine and Pt-decorated SnS monolayers using density functional theory (DFT) calculations. Pristine SnS monolayers have limited charge transfer and long adsorption distances to VOC molecules, resulting in VOC insensitivity. The introduction of Pt atoms promotes charge transfer, creates new energy levels, and increases the overlap of the density of states, thereby enhancing electron excitation and improving gas sensitivity. Pt-decorated SnS monolayers exhibited high sensitivities of 241,921.7%, 35.7%, and 74.3% towards C2H4, C2H6, and C6H6, respectively. These values are 142,306.9, 23.8, and 82.6 times higher than those of pristine SnS monolayers, respectively. Moreover, the moderate adsorption energies of adsorbing C2H6 and C6H6 molecules ensure that Pt-decorated SnS monolayers possess good reversibility with a short recovery time at 298 K. When heated to 498 K, C2H4 molecules desorbs from the surface of Pt-decorated SnS monolayer in 162.33 s. Our results indicate that Pt-decorated SnS monolayers could be superior candidates for sensing VOCs with high selectivity, sensitivity, and reversibility.

Clever Nanomaterials Fabrication Techniques Encounter Sustainable C1 Catalysis.

ConspectusC1 catalysis, which refers to the conversion of molecules with a single carbon atom, such as CO, CO2, and CH4, into clean fuels and basic building blocks for chemical industries, has built a bridge between carbon resource utilization and valuable chemical supply. With respect to the goal of carbon neutrality, C1 catalysis also plays an essential role owing to its integrated functions in the green catalytic process with fewer CO2 emissions and even direct high-value-added utilization of greenhouse gases (CO2 and CH4). However, the inert nature of the C-O or C-H bond in C1 molecules as well as uncontrollable C-C coupling render C1 catalysis challenging. The rational design of highly active catalytic materials (denoted as C1 catalysts) with strong capacities for C-O or C-H bond activation and C-C coupling by convenient nanomaterials fabrication methods to boost the catalytic performance of C1 molecule conversion, including targeted product selectivity and long-term stability, is the cornerstone of C1 catalysis.Notably, the familiar concepts in heterogeneous catalysis, such as tandem catalysis and confinement catalysis, are applicable for C1 catalysis and have been successfully used to design a C1 catalyst. Regarding the tandem catalysis concept that integrates multiple reactions in a single-pass via a bi- or multifunctional catalyst, it is promising to shed new light on the oriented conversion of C1 molecules, especially for C2+ hydrocarbon or oxygenate synthesis. The confinement effect is powerful for controlling the product distribution and enhancing activation efficiency of inert chemical bonds in C1 catalysis due to the unique reactants/intermediate adsorption and evolution behaviors on the confined catalytic interface with a special electronic environment. Moreover, metal-support interactions (MSIs), electronic properties of the active site, and catalytic engineering issues are also susceptible to the C1 molecule conversion performance. Therefore, under the guidance of basic and novel rules in heterogeneous catalysis, the innovation of catalytic materials with the aid of advanced catalytic materials fabrication techniques has always been a hot research topic in C1 catalysis.In this Account, we briefly describe the challenges in thermal-catalytic C1 molecule (mainly CO, CO2, and CH4) conversion. At the same time, the synergistic functioning of the physicochemical properties of the catalytic materials on the performance in C1 molecule conversion is highlighted. More importantly, we summarize our progress in rationally designing tailor-made C1 catalysts to enhance C1 molecule activation efficiency and targeted product selectivity via powerful nanomaterials fabrication techniques, such as traditional wet-chemistry strategies, the magnetron sputtering method, and 3D printing technology. Specifically, the ingenious capsule catalyst and ammonia pools in zeolites fabricated by a wet chemistry process possess an extraordinary effect on the transformation of CO, CO2, and CH4 molecules. Also, the sputtering method is reliable in modulating the electronic properties of metallic active sites for C1 molecule conversion, thereby tailoring the final product selectivity. Furthermore, we showcase the strong capability of metal 3D printing technology in fabricating a self-catalytic reactor, by which the functions of the reaction field and nanoscale active sites are well integrated. Finally, we predict the future research opportunities in highly efficient C1 catalyst design with the assistance of clever nanomaterials fabrication techniques.