Conjugated π Electrons of MOFs Drive Charge Separation at Heterostructures Interface for Enhanced Photoelectrochemical Water Oxidation

Abstract

Photoanode material with high efficiency and stability is extensively desirable in photoelectrochemical (PEC) water splitting for green/renewable energy source. Herein, novel heterostructures is constructed via coating rutile TiO2 nanorods with metal organic framework (MOF) materials UiO‐66 or UiO‐67 (UiO‐66@TiO2 and UiO‐67@TiO2), respectively. The π electrons in the MOF linkers could increase the local electronegativity near the heterojunction interface due to the conjugation effect, thereby enhancing the internal electric field (IEF) at the heterojunction interface. The IEF could drive charge transfer following Z‐scheme mechanism in the prepared heterostructures, inducing photogenerated charge separation efficiency increasing as 156% and 253% for the UiO‐66@TiO2 and UiO‐67@TiO2, respectively. Correspondingly, the UiO‐66@TiO2 and UiO‐67@TiO2 enhanced the photocurrent density as approximate two‐ and threefolds compared with that of pristine TiO2 for PEC water oxidation in universal pH electrolytes. This work demonstrates an effective method of regulating the IEF of heterojunction toward further improved charge separation.

Tunable Competitive Absorption-Induced Signal-On Photoelectrochemical Immunoassay for Cardiac Troponin I Based on Z-Scheme Metal–Organic Framework Heterojunctions

“…The scheme shows that when Zr-MOF@TiO 2 NRs are excited, spontaneous migration of photogenerated electrons from the CB of Zr-MOF to the VB of TiO 2 occurs at the contact interface. Hence, a direct Z-scheme heterojunction is formed, which agrees with studies elsewhere . Because the TiO 2 NRs are in direct contact with the surface of FTO, the photogenerated electron transfer pathway from outer shell Zr-MOF to inner TiO 2 NRs is feasible, as evidenced by the improved photocurrent signal of Zr-MOF@TiO 2 NRs.…”

Enhanced photocatalytic activity of TiO2/UiO-67 under visible-light for aflatoxin B1 degradation

“… 30 Zhang et al synthesized TiO 2 /mag-101(Cr) combined the advantages of TiO 2 , MOFs and Fe 3 O 4 to improve photocatalysis degradation efficiency of organic pollutants. 31 In recent years, UiO-67, one of the Zr-MOFs, has large surface area, good photocatalysis activity and lower bandgap (3.14 eV), 32 which has better light response than TiO 2 . 33 Therefore, designing TiO 2 /UiO-67 heterostructures is a feasible approach for improving the photocatalytic activities of TiO 2 .…”

2D Bismuthene Metal Electron Mediator Engineering Super Interfacial Charge Transfer for Efficient Photocatalytic Reduction of Carbon Dioxide

“…This heterostructure of C 3 N 4 /bismuthene/BiOCl (CNBB) is successfully implemented by a facile solvothermal method. 2D bismuthene was innovatively applied in a Z-scheme system, shortening the charge transfer distance as an electron mediator, as well as enlarging the interface contact area and balancing the accumulated surplus charge. − As-prepared CNBB performs with a high photocatalytic stability and high product yields of CO 2 conversion to CO and CH 4 . − The photocorrosion of the BiOCl/C 3 N 4 system is surmounted by 2D bismuthene serving as a charge transfer and recombination center. This mechanism is confirmed by the charge density differences from the DFT calculation and the ultrafast spectrum experiments.…”