Integrating Single Atoms with Different Microenvironments into One Porous Organic Polymer for Efficient Photocatalytic CO₂ Reduction

Abstract

The precise identification of single‐atom catalysts (SACs) activity and boosting their efficiency toward CO2 conversion is imperative yet quite challenging. Herein, for the first time a series of porous organic polymers is designed and prepared simultaneously, containing well‐defined M–N4 and M–N2O2 single‐atom sites. Such a strategy not only offers multiactive sites to promote the catalytic efficiency but also provides a more direct chance to identify the metal center activity. The CO2 photoreduction results indicate that the introduction of salphen unit with Ni–N2O2 catalytic centers into pristine phthalocyanine‐based Ni–N4 framework achieves remarkable CO generation ability (7.77 mmol g–1) with a high selectivity of 96% over H2. In combination with control experiments, as well as theoretical studies, the Ni–N2O2 moiety is evidenced as a more active site for CO2RR compared with the traditional Ni–N4 moiety, which can be ascribed to the M–N2O2 active sites effectively reducing the energy barrier, facilitating the adsorption of reaction radicals *COOH, and improving the charge transportation. This work might shed some light on designing more efficient SACs toward CO2 reduction through modification of their coordination environments.

Replacing Ru complex with carbon dots over MOF-derived Co3O4/In2O3 catalyst for efficient solar-driven CO2 reduction

“…1–3 The photocatalytic CO 2 reduction reaction suffers from poor activity and product selectivity, as a result of the complex multi-electron transfer path involved. 4–7 Considerable efforts have been made to enhance the photocatalytic CO 2 reduction activity, such as using photosensitizer and/or cocatalyst modification, 8 morphology engineering, 9 doping 10 and heterojunction construction. 11 Among these, the addition of photosensitizer, which can boost the charge transfer efficiency and provide more active sties to activate photocatalytic molecules, has, so far, been widely investigated.…”

Considering single-atom catalysts as photocatalysts from synthesis to application

“…This unavoidable energy loss before the surface reaction would result in relatively low photocatalytic activity. The introduction of SAs is also demonstrated to contribute to efficient carrier separation ( Dong et al., 2021b ; Xiao et al., 2020 ). According to the previous studies, generally, when the metal nanoparticle is in contact with the semiconductor, a Schottky barrier is generated on behalf of the energy level matching of the metal and the semiconductor.…”

Hydrophobic perfluoroalkane modified metal‐organic frameworks for the enhanced electrocatalytic reduction of CO2

“…In recent years, extensive efforts have been devoted to exploit highly efficient electrocatalysts for the electrochemical CO 2 -to-CO conversion. The electrode materials such as Au-, Ag-, Cu-based metals, [26][27][28] Fe, Co, Ni-based single-atom catalysts (SACs), [29][30][31][32][33] metal-free carbon materials [34][35][36] have been developed. However, the drawbacks including high cost of noble metals, difficult to prepare SACs in large-scale synthesis restricted their commercial applications in the CO 2 RR.…”