Chemically Exfoliated Semiconducting Bimetallic Porphyrinylphosphonate Metal–Organic Layers for Photocatalytic CO₂ Reduction under Visible Light

Abstract

In this paper, we report the first example of semiconducting porphyrinylphosphonate metal−organic framework (MOF) [Co(Ni-H 7 TPPP) 2 ]•8H 2 O and its chemical exfoliation into ultrathin metal−organic layers (MOLs) with an electric conductivity up to 0.12 S cm −1 at RT. Benefiting from the 2D layered structure possessing highly accessible metalloporphyrin-active motifs, a negatively charged surface, and a phosphonate-enhanced structural stability, the exfoliated MOL enables the material to behave as an efficient cocatalyst in coordination with positively charged [Ru-(bpy) 3 ] 2+ to photocatalytically reduce CO 2 to CO in a high yield rate (3.16 × 10 4 μmol g −1 h −1 ) and selectivity (81%). Spectroscopic studies engaging DRS, UPS, PL, EIS, and TPR unanimously point to the remarkable photocatalytic performance being a result of proper band alignment among the system components and great charge extraction capability of the cocatalyst. More importantly, by explicitly dissecting the band structure and charge transport behavior, this study provides insights into catalyst design to afford a coherent energy flow in hybrid photocatalytic systems.

Construction of Novel Coordination Polymers Based on Pyrazole Carboxylic Acid and Doping for Enhancing the Photocatalytic Property Under Visible Light

“…Recently, the rational design and synthesis of functional coordination polymers (CPs) have received considerable attention due to their diverse structures and potential applications in sorption, catalysis, luminescent materials, magnetism, proton conductivity, etc. − In these potential applications, some CPs have shown photocatalytic performance in reducing carbon dioxide, splitting water, degrading environmental pollutants, etc. − because these functional CPs exhibit an efficient separation of photogenerated charge carriers. Accordingly, a lot of interest has been paid to developing novel CPs photocatalytic catalysts through varying organic bridging linker structures and metal ions with different electronic configurations. ,− …”

Layered Uranyl Phosphonates Encapsulating Co(II)/Mn(II)/Zn(II) Ions: Exfoliation into Nanosheets and Its Impact on Magnetic and Luminescent Properties

“…[30] In this context, layered metal phosphonates with strong in-plane and weak inter-plane interactions provide ideal platforms to fabricate atomically thick 2D materials with interesting physicochemical properties, but examples are still rather limited. [31][32][33][34][35][36][37][38] Heterobimetallic 5f-3d uranyl phosphonates with layered structures offer possibilities to investigate their optical and magnetic properties in the forms of both crystalline bulk and 2D limit. However, there has been no published report dealing with this topic.…”

“…Such 2D materials possess precisely determined atomic structures and may exhibit physicochemical properties different from their bulk counterparts [30] . In this context, layered metal phosphonates with strong in‐plane and weak inter‐plane interactions provide ideal platforms to fabricate atomically thick 2D materials with interesting physicochemical properties, but examples are still rather limited [31–38] . Heterobimetallic 5f–3d uranyl phosphonates with layered structures offer possibilities to investigate their optical and magnetic properties in the forms of both crystalline bulk and 2D limit.…”

Sacrificial agent-free photocatalytic CO2 reduction using a 2D cobalt porphyrin-based MOF/graphene heterojunction

“…17 Qin et al utilized an ultrathin bimetallic MOF [Co(Ni-H 7 TPPP) 2 ]·8H 2 O as a cocatalyst to reduce CO 2 to CO in the presence of a [Ru(bpy) 3 ] 2+ photosensitizer. 18 More recently, Sillanpää et al synthesized a 2D Co-porphyrin MOF (Co-PMOF) and used it as a photocatalyst for the reduction of CO 2 to formate (HCOO − ). 19 Although 2D MOFs show great potential in photocatalysis, the research on 2D MOF-based materials is still in its infancy, especially for the photocatalytic reduction of CO 2 .…”