Comprehensive Mechanism of CO₂ Electroreduction on Non‐Noble Metal Single‐Atom Catalysts of Mo₂CS₂‐MXene

Abstract

In this work, a series of non‐noble metal single‐atom catalysts of Mo2CS2‐MXene for CO2 reduction were systematically investigated by well‐defined density‐functional‐theory (DFT) calculations. It is found that nine types of transitional metal (TM) supported Mo2CS2 (TM‐Mo2CS2) are very stable, while eight can effectively inhibit the competitive hydrogen evolution reaction (HER). After comprehensively comparing the changes of free energy for each pathway in CO2 reduction reaction (CO2RR), it is found that the products of TM‐Mo2CS2 are not completely CH4. Furthermore, Cr‐, Fe‐, Co‐ and Ni‐Mo2CS2 are found to render excellent CO2RR catalytic activity, and their limiting potentials are in the range of 0.245–0.304 V. In particular, Fe‐Mo2CS2 with a nitrogenase‐like structure has the lowest limiting potential and the highest electrocatalytic activity. Ab initio molecular dynamics (AIMD) simulations have also proven that these kinds of single‐atom catalysts with robust performance could exist stably at room temperature. Therefore, these single TM atoms anchored on the surface of MXenes can be profiled as a promising catalyst for the electrochemical reduction of CO2.

MXenes as Electrocatalysts for the CO2 Reduction Reaction: Recent Advances and Future Challenges

“…Fe@W 2 CS 2 SAC & Fully À S term U L = À 0.245 V COOH*!CO* CO [46] Ru@Mo 2 CS 2 SAC & Fully À S term electrocatalytic reduction of CO 2 with a small U L and tuned selectivity. Improved modeling has highlighted how, in addition to the inherent MXene activity, the presence of certain surface terminations or mixed situations can affect the free energies of key CO 2 RR intermediates or open new reaction pathways, ultimately resulting in a reduction of the energetic costs of the PDS.…”

“…In the early early-stage of catalyst design one should also consider the synthetic feasibility, with negative formation energies, E f < 0, and the electrochemical stability, with positive dissolution potentials, U diss > 0 V. [43] Pourbaix diagrams should be also utilized to determine the catalyst surface composition and stability. [48,53] In the SAC context, the TM adsorption energy is far from being sufficient, [46] and a comparison between the TM adsorption and bulk TM cohesive energies is needed to properly evaluate the TM SAC thermodynamic stability. Better when accounting for dynamic stability when inspecting the TM adatom diffusion energy.…”

Computational Screening of Pt1@Ti3C2T2 (T = O, S) MXene Catalysts for Water–Gas Shift Reaction

“…In addition to the supported single metal atoms, the support itself also plays a key role in dictating the catalytic performance. MXenes, as a new type of two-dimensional layered metal carbide, nitride, and carbonitride material, have excellent conductivity and chemical stability, which were obtained from the MAX phase by an etching method reported by Gogotsi et al Due to their variable atom types, atomic layer thickness, the surface terminated groups, and surface defect types which can regulate the hydrophilicity, conductivity, surface work function, and the catalytic activity, MXenes are suitable as a substrate for anchoring single atoms to form SACs, − which are used in various fields, such as energy conversion, energy storage materials, sensors and electrocatalytic reactions, ORR, ,, HER, CO 2 RR, − NRR, − and so on. Moreover, small molecules can be effectively activated and transformed .…”

Unveiling the key intermediates in electrocatalytic synthesis of urea with CO2 and N2 coupling reactions on double transition-metal MXenes

“…MXenes are two-dimensional layered transition metal carbides or nitrides with graphene-like structures. Since their discovery by Gogotsi et al, 12 they have been widely investigated in the eld of electrocatalysis, such as in the catalytic hydrogen evolution reaction (HER), [13][14][15] oxygen evolution reaction (OER), 16,17 carbon dioxide reduction reaction (CO 2 RR), [18][19][20] and nitrogen reduction reaction (NRR), [21][22][23] because of their high specic surface area, multiple exposed active sites, and tunable electronic structure. Double transition metal MXenes with two different transition metals have more peculiar properties.…”