Embedding Group VIII Elements into a 2D Rigid pc-C3N2 Monolayer to Achieve Single-Atom Catalysts with Excellent OER Activity: A DFT Theoretical Study

Abstract

Under DFT calculations, a systematic investigation is carried out to explore the structures and oxygen evolution reaction (OER) catalytic activities of a series of 2D single-atom catalyst (SAC) systems, which are constructed by doping the transition metal (TM) atoms in group VIII into the cavities of rigid phthalocyanine carbide (pc-C3N2). We can find that when Co, Rh, Ir and Ru atoms are doped in the small or large cavities of a pc-C3N2 monolayer, they can be used as high-activity centers of OER. All these four new TM@C3N2 nanostructures can exhibit very low overpotential values in the range of 0.33~0.48 V, even smaller than the state-of-the-art IrO2 (0.56 V), which indicates considerably high OER catalytic activity. In particular, the Rh@C3N2 system can show the best OER performance, given that doped Rh atoms can uniformly serve as high-OER-active centers, regardless of the size of cavity. In addition, a detailed mechanism analysis was carried out. It is found that in these doped pc-C3N2 systems, the number of outer electrons, the periodic number of doped TM atoms and the size of the embedded cavity can be considered the key factors affecting the OER catalytic activity, and excellent OER catalytic performance can be achieved through their effective cooperation. These fascinating findings can be advantageous for realizing low-cost and high-performance SAC catalysts for OER in the near future.

Metal-Doped C3B Monolayer as the Promising Electrocatalyst for Hydrogen/Oxygen Evolution Reaction: A Combined Density Functional Theory and Machine Learning Study

“…At last, we compare the HER/OER performances of our proposed electrocatalysts with those of other reported materials. In the cases of HER, monolayer MoSi 2 N 4 , Ni-doped β-Sb, Co–Mo 5 N 6 heterojunction, Ni-doped graphene, and AgPd alloys were considered as the excellent HER catalysts, and the corresponding |η HER | values are within 0.01–0.10 V, whose catalytic activities are similar to or even better than that of the Pt(111) surface (|η HER | = 0.09 eV) . In the cases of OER, it is found that the Rh-borophane, Rh-doped C 2 N, Ni-doped Mo 2 B 2 , Rh–N 4 –, and Ni/Pd–C 4 -doped graphene are promising candidates as OER catalysts, with the η OER values in the range of 0.31–0.53 V, which can compete with the most advanced IrO 2 (η OER = 0.56 V) and RuO 2 (η OER = 0.42 V) catalysts .…”

“…In the cases of HER, monolayer MoSi 2 N 4 , 63 Nidoped β-Sb, 64 Co−Mo 5 N 6 heterojunction, 65 Ni-doped graphene, 66 and AgPd alloys 54 were considered as the excellent HER catalysts, and the corresponding |η HER | values are within 0.01−0.10 V, whose catalytic activities are similar to or even better than that of the Pt(111) surface (|η HER | = 0.09 eV). 67 In the cases of OER, it is found that the Rh-borophane, 12 Rhdoped C 2 N, 68 Ni-doped Mo 2 B 2 , 69 Rh−N 4 −, and Ni/Pd−C 4doped graphene 11 are promising candidates as OER catalysts, with the η OER values in the range of 0.31−0.53 V, which can compete with the most advanced IrO 2 (η OER = 0.56 V) and RuO 2 (η OER = 0.42 V) catalysts. 2 In addition, some excellent bifunctional catalysts by combining HER and OER functions have been proposed, such as Ni-and Cu-doped MXenes, 13 Mn−Ni 3 S 2 , 70 and Ni-doped Mo 2 B 2 , 71 whose |η HER | and η OER values are within the range of 0.02−0.24 and 0.25−0.52 V, respectively.…”

From Porphyrin-Like Rings to High-Density Single-Atom Catalytic Sites: Unveiling the Superiority of p-C2N for Bifunctional Oxygen Electrocatalysis

“…To describe the electronic structure of the material, using the PBE function and the k -point path of Figure d, we calculated the band structure of the p-C 2 N monolayer, as shown in Figure e. As we expected, the valence band maximum (VBM) and conduction band minimum (CBM) of p-C 2 N both cross the Fermi level similar to other PGCNs with porphyrin-like units, − indicating metallic properties and suggesting high charge transfer capability. The relevant electronic density of states (DOS) and projected electronic density of states (PDOS) imply bonding types and strengths, as depicted in Figure f.…”

Experimentally revealed and theoretically certified synergistic electronic interaction of V-doped CoS for facilitating the oxygen evolution reaction

“…2(a)-(c)). 29,30 Similarly, the projected density of states (PDOS) of the three substrates indicated that the VCoS catalyst has the highest density of states near the Fermi level (Fig. 2(d)-(f)).…”