sp‐Carbon Incorporated Conductive Metal‐Organic Framework as Photocathode for Photoelectrochemical Hydrogen Generation

Abstract

Metal-organic frameworks (MOFs) have attracted increasing interest for broad applications in catalysis and gas separation due to their high porosity. However, the insulating feature and the limited active sites hindered MOFs as photocathode active materials for application in photoelectrocatalytic hydrogen generation. Herein, we develop a layered conductive twodimensional conjugated MOF (2D c-MOF) comprising sp-carbon active sites based on arylene-ethynylene macrocycle ligand via CuO 4 linking, named as Cu 3 HHAE 2 . This sp-carbon 2D c-MOF displays apparent semiconducting behavior and broad light absorption till the near-infrared band (1600 nm). Due to the abundant acetylene units, the Cu 3 HHAE 2 could act as the first case of MOF photocathode for photoelectrochemical (PEC) hydrogen generation and presents a record hydrogen-evolution photocurrent density of � 260 μA cm À 2 at 0 V vs. reversible hydrogen electrode among the structurally-defined cocatalyst-free organic photocathodes.

Stabilizing Redox‐Active Hexaazatriphenylene in a 2D Conductive Metal–Organic Framework for Improved Lithium Storage Performance

“…[32,34] Ultraviolet-visible-near-infrared (UV-vis-NIR) spectrum shows that Cu-HATN has a wide absorption band extending to the 1800 nm NIR region, and the band gap was calculated to be 0.46 eV based on the value of absorption edge (Figure S18, Supporting Information), indicating the semiconductive behavior of Cu-HATN. [35,36] The higher experimental value of band gap than the theoretical band gap may be due to the influence of domain boundaries, impurities, and defects in polycrystalline MOFs. [37,38] The electrical conductivity of Cu-HATN was further evaluated in the pressed bulk sample with the two-contact probe method under ambient conditions, revealing a moderate conductivity of ≈2.15 × 10 −6 S m −1 (Figure S19, Supporting Information).…”

Applications of Metal–Organic Frameworks and Their Derivatives in Electrochemical CO2 Reduction

“…Choosing electron-donating ligands as well as their orientation and bonding arrangements is an efficient strategy to improve the conductivity of MOFs, these functional groups can increase the conductivity of MOFs by creating pathways for the flow of electrons and increasing the density of free electrons in the material [ 114 – 116 ]. Owing to the high overlap of d- π conjugation orbitals between the nickel node and the planar Ni-phthalocyanine-substituted X (X: o-phenylenediamine or catechol), Zhang et al [ 98 ] employed Ni-phthalocyanines (NiPc) as the building block for the construction of a porous intrinsically conductive two-dimensional (2D) MOF (NiPc-Ni(NH) 4 ).…”

Metal–Organic Framework‐Based Photocatalysis for Solar Fuel Production

“…[224][225][226] Besides, to achieve the ultimate goal of efficient solar-to-chemical conversion, researchers can pay attention to the coupling catalysis between photocatalysis and electrocatalysis, or thermal catalysis. [227][228][229][230][231] As an outcome, MOFs for photoelectrochemical cells (PECs) to generate solar fuels have attracted rapidly growing interest. The pristine MOFs can act as a porous scaffold to immobilize and stabilize photosensitizers, redox shuttles, and molecular electrocatalysts, which are the three needed ingredients to establish a highly effective dye-sensitized PEC system.…”