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Developing highly efficient catalysts for carbon dioxide reduction reaction (CO2RR) is significant in producing useful chemicals and alleviating environmental pollution. Herein, a series of two-dimensional TM-PTC (TM = Sc-Zn, PTC = 1,2,3,4,5,6,7,8,9,10,11,12-perthiolated coronene) frameworks as CO2RR electrocatalysts are investigated based on the density functional method. The calculated results showed that the main product is CH4 for TM-PTC (TM = Sc-Mn). However, these catalysts can be poisoned by water molecules due to its strong adsorption on the catalyst surface. To solve the problem, we modified these catalysts by adding axial oxygen (TM-O-PTC). Our study showed that TM-O-PTC (TM = V, Cr) are good catalysts for CO2RR to produce CH4. We expected that this work could provide a useful strategy for developing high-performance CO2RR electrocatalysts. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) provides a feasible technology for alleviating global warming, energy crisis and sustainable energy production. In this work, CO2RR reaction mechanism on TM-THTA (TM = Fe , Co, Ni, Ru, Rh, Pd, THTA is composed by two types of building blocks of 2,3,6,7,10,11-triphenylenehexathiol and 2,3,6,7,10,11-triphenylenehexamine) has been studied by using density functional method. Our study showed that the studied catalysts are stable both thermodynamically and electrochemically. Rh-THTA is a good CO2 reduction catalyst in producing CH4. Pd-THTA is a potential CO2 reduction catalyst in producing HCOOH. Solvent effect plays important role in reaction mechanism. The strong hydrogen evolution reaction in Rh-THTA and Pd-THTA can be refrained by adjusting the pH values of electrolyte. We hope this study could provide a useful way to develop 2D-MOF-based CO2RR electrocatalysts. [ABSTRACT FROM AUTHOR]

The reduction of CO2 into valuable chemicals through electrocatalytic techniques provides a potential strategy to alleviate energy crises and environmental pollution. In this study, 2D M3(THT)2 (M = Fe, Co, Ni, Ru, Rh, Pd, THT = 2,3,6,7,10,11-triphenylenehexathiolate) framework as CO2 reduction reaction (CO2RR) electrocatalysts was investigated by using the density functional method. The results showed that the studied catalysts are stable both thermodynamically and electrochemically. Rh3(THT)2 exhibits the best catalytic performance to produce CH4 with the overpotential of 0.61 V in the gas phase and 0.63 V in solution. The inactive hydrogen evolution reaction in Rh3(THT)2 would favour CO2RR. For Fe3(THT)2 and Ru3(THT)2, the main product is CO. However, the strong CO adsorption on the catalyst surface can lead to catalyst to be poisoned, which makes Fe3(THT)2 and Ru3(THT)2 to be poor CO2RR catalysts. We anticipate that this work may provide a new avenue for the development of high-performance 2D metal-organic framework-based electrocatalysts. [ABSTRACT FROM AUTHOR]

Metal–organic porous materials provide a feasible strategy for designing electrocatalysts due to high surface area and well-defined porous structures. Herein, the catalytic activity and reaction mechanism for oxygen reduction reaction (ORR) on bis(iminothiolato)rhodium (RhIT) monolayer have been investigated by means of density functional theory. Our results indicate that *OOH hydrogenation to form *OH + *OH pathway is the kinetically most favourable pathway. The formation of two *OH intermediates is the rate-determining step with an energy barrier of 0.89 eV, close to 0.80 eV for pure Pt catalyst. The calculated working potential is 0.79 V, which is also close to 0.78 V for pure Pt. Thus, RhIT could be a potential ORR catalyst. We expect that the results of this work can offer fundamental insights for the design of highly efficient ORR catalysts by two-dimensional MOFs materials. [ABSTRACT FROM AUTHOR]

The development of high efficient cathode catalyst is known to be very important for the large-scale application of fuel cells. In this work, by using the density functional theory, metal-porphyrin (M = Mn, Co) carbon materials (Mn/CoN4-C) have been investigated as possible oxygen reduction reaction (ORR) catalysts. The calculated formation energies indicate that Mn/CoN4-C is stable thermodynamically. For MnN4-C, ORR proceeds with a four-electron process. While for CoN4-C, both two-electron pathway and four-electron pathway are competitive, with the former being slightly favoured. For both compounds, the O2 hydrogenation pathway is favoured compared with O2 dissociation pathway. In CoN4-C, the energy barrier is 0.13 eV for the two-electron pathway, while it is 0.47 eV for the four-electron pathway, much lower than 0.80 eV for pure Pt. These energy barriers are also much lower than that in MnN4-C, showing that CoN4-C has a better ORR activity than MnN4-C. The calculated working potential is 0.30 eV for CoN4 in the four-electron pathway. [ABSTRACT FROM AUTHOR]

The oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR) have attracted worldwide attention in order to solve the energy crisis and global warming. In this work, we have investigated the ORR and CO2RR activity of Fe-porphyrin carbon material (FeN4-C) by using the density functional method. The catalytic active sites are identified based on the charge transfer analysis and it is found that FeN4 moiety and its adjacent eight C atoms are the active centre. ORR proceeds via a four-electron process. The OOH hydrogenation into O + H2O is the most favourable pathway with the rate-determining step to be the formation of OOH. The energy barrier is 0.09 eV, much smaller than 0.56 eV for FeN4 doped graphene and 0.80 eV for pure Pt. The predicted working potential is 0.52 V, larger than 0.35 V for FeN4 doped graphene. For CO2RR, CO2 tends to be reduced to HCHO and CH3OH with the limiting potential of −0.62 V. HCOOH is the minor product. In a word, the above results suggested that FeN4-C is a promising bifunctional electrocatalyst for both ORR and CO2RR. [ABSTRACT FROM AUTHOR]