Single-Atom Cobalt Incorporated in a 2D Graphene Oxide Membrane for Catalytic Pollutant Degradation

Abstract

We introduce a new graphene oxide (GO)-based membrane architecture that hosts cobalt catalysts within its nanoscale pore walls. Such an architecture would not be possible with catalysts in nanoscale, the current benchmark, since they would block the pores or alter the pore structure. Therefore, we developed a new synthesis procedure to load cobalt in an atomically dispersed fashion, the theoretical limit in material downsizing. The use of vitamin C as a mild reducing agent was critical to load Co as dispersed atoms (Co1), preserving the well-stacked 2D structure of GO layers. With the addition of peroxymonosulfate (PMS), the Co1-GO membrane efficiently degraded 1,4-dioxane, a small, neutral pollutant that passes through nanopores in single-pass treatment. The observed 1,4-dioxane degradation kinetics were much faster (>640 times) than the kinetics in suspension and the highest among reported persulfate-based 1,4-dioxane destruction. The capability of the membrane to reject large organic molecules alleviated their effects on radical scavenging. Furthermore, the advanced oxidation also mitigated membrane fouling. The findings of this study present a critical advance toward developing catalytic membranes with which two distinctive and complementary processes, membrane filtration and advanced oxidation, can be combined into a single-step treatment.

Insights into singlet oxygen generation and electron-transfer process induced by a single-atom Cu catalyst with saturated Cu-N4 sites

“…Additionally, the insignificant alteration in the Raman and FTIR spectra of NC and SA-Cu-NC indicates that the introduction of Cu exerts a negligible influence on the structure of the carbon framework (Figures S4 and S5) (Gao et al, 2021b). Figure 2C shows that numerous well-isolated atoms marked with red circles are observed in the aberration-corrected HAADF-STEM image, confirming that the Cu species in SA-Cu-NC exist as single atoms (Wu et al, 2022). Additionally, the EDX mapping images (Figures 2D-2G) of SA-Cu-NC further reveal that Cu and N atoms are uniformly dispersed over the entire carbon substrate.…”

Catalytic Membrane with Copper Single-Atom Catalysts for Effective Hydrogen Peroxide Activation and Pollutant Destruction

“…Currently reported catalytic membranes are usually functionalized with nanoparticulate catalysts ( e.g. , Fe/Pt NPs, MnO 2 , FeOCl, and CuFe 2 O 4 ,), which block membrane pores and severely compromise water flux (40–80% decrease). ,, Seeding membranes with SACs can potentially address this problem . However, such membranes have rarely been reported due to the lack of functional groups on membrane supports that can maintain the activity and stability of SACs.…”

A nanoclay-confined single atom catalyst: tuning uncoordinated N species for efficient water treatment

“…These are generally related to the coordination structure of NG-SACs. [12][13][14][15] Considering these features, we evaluated the role of uncoordinated N species in PMS activation, which is vital for the rational design of NG-SACs in environmental remediation. Developing a tunable and predictable approach for the synthesis of NG-SACs is critical to establishing the correlation between uncoordinated N species and catalytic properties of NG-SACs.…”

“…They can generate versatile reactive intermediates (sulfate radical , superoxide radicals , hydroxyl radicals (˙OH), and singlet oxygen ( 1 O 2 )) for pollutant removal. 12–15 These reactive processes can occur via a nonradical pathway to produce 1 O 2 or via a radical pathway to form ˙OH, , and . These are generally related to the coordination structure of NG-SACs.…”

“…These are generally related to the coordination structure of NG-SACs. 12–15 Considering these features, we evaluated the role of uncoordinated N species in PMS activation, which is vital for the rational design of NG-SACs in environmental remediation.…”