Engineering Low-Coordination Single-Atom Cobalt on Graphitic Carbon Nitride Catalyst for Hydrogen Evolution

Abstract

Although single-atom catalysts (SACs) have been at the vanguard of energy conversion research, the selection of suitable substrates and single-atom specification permits remains ambiguous. Herein, we fabricated Co-g-C3N4/rGO SACs (Co-CNG) by coupling the suitable single-atom Co with a promising substrate of g-C3N4/rGO. Remarkably, Co-CNG exhibits even comparable HER performance (10 mA cm–2 at ∼47 mV) with commercially available Pt/C (10 mA cm–2 at ∼48 mV) and outperformed non-noble transition-metal SACs under alkaline conditions since its mass activity is about 4 times that of Pt/C with the long-term durability of 500 h. Athena fitting of Co-CNG was conducted, revealing its two types of coordination structure, including 20% of Co-N and 80% of Co-3N. Notably, the Co-N coordination structure is responsible for boosting HER due to its downshift d-band center, unique electronic structures, and low free energy barriers based on density functional theory. This study not only reveals that Co-CNG shows HER performance due to its unique SACs coordination of Co-N but also proves a way for catalyst optimization by specifically coordination engineering for particular applications.

Bias‐Free Solar‐Driven Syngas Production: A Fe2O3Photoanode Featuring Single‐Atom Cobalt Integrated with a Silver‐Palladium Cathode

“…A conspicuous Fourier transforms (FT) peak at 1.49 Å is clearly observed, which was indexed to CoÀ N bonds with a coordination number of 4 (Figure S3 and Table S1). [19] Furthermore, the corresponding wavelet transform (WT) demonstrates only one intensity maximum at 4 Å À 1 , further confirming the atomically dispersed Co atoms in the obtained CoÀ C 3 N 4 samples (Figure 1C). Subsequently, the CoÀ C 3 N 4 nanosheets were decorated on hierarchical Fe 2 O 3 nanoarrays to construct Fe 2 O 3 /CoÀ C 3 N 4 photoanodes (Scheme S2).…”

Electron-Deficient Zn-N6 Configuration Enabling Polymeric Carbon Nitride for Visible-Light Photocatalytic Overall Water Splitting

“…2 a), the absorption threshold for Zn-PCN is significantly higher than that for Zn foil and even higher than that for ZnO, indicating that Zn single atoms in Zn-PCN exist at an oxidation state higher than that of Zn 2+ and hold more unoccupied states than Zn 2+ [ 29 , 31 ], as further confirmed by that the characteristic peaks of Zn 2 p 3/2 and Zn 2 p 1/2 levels for Zn-PCN shift to higher binding energies as compared to ZnO in the Zn 2 p XPS spectra (Fig. 2 b) [ 35 ]. Considering that Zn 2+ has a 3 d 10 electron configuration, Zn single atoms should possess a partially vacant 3 d orbital (inset in Fig.…”

DFT Investigation of Single Metal Atom-Doped 2D MA2Z4 Materials for NO Electrocatalytic Reduction to NH3

“…It is crucial to have an appropriate substrate to support atomically dispersed catalysts, especially for building the structure analogues to M 1 –N x . , The side and top views of the geometrical configuration of MA 2 Z 4 are shown in Figure a. The N, P, or As atomic layer is the outermost one of septuple sandwich-shaped MA 2 Z 4 .…”