WO₃/Conducting Polymer Heterojunction Photoanodes for Efficient and Stable Photoelectrochemical Water Splitting

Abstract

An efficient and stable heterojunction photoanode for solar water oxidation was fabricated by hybridization of WO and conducting polymers (CPs). Organic/inorganic hybrid photoanodes were readily prepared by the electropolymerization of various CPs and the codeposition of tetraruthenium polyoxometalate (RuPOM) water-oxidation catalysts (WOCs) on the surface of WO. The deposition of CPs, especially polypyrrole (PPy) doped with RuPOM (PPy:RuPOM), resulted in a remarkably improved photoelectrochemical performance by the formation of a WO/PPy p-n heterojunction and the incorporation of efficient RuPOM WOCs. In addition, there was also a significant improvement in the photostability of the WO-based photoanode after the deposition of the PPy:RuPOM layer due to the suppression of the formation of hydrogen peroxide, which was responsible for corrosion. This study provides insight into the design and fabrication of novel photosynthetic and photocatalytic systems with excellent performance and stability through the hybridization of organic and inorganic materials.

Modulating Charge Separation Efficiency of Water Oxidation Photoanodes with Polyelectrolyte‐Assembled Interfacial Dipole Layers

“…and hydrocarbons. [4] In this regard, various materials are being explored for efficient photogeneration of excitons and their catalytic applications, including Fe 2 O 3 , [7][8][9] BiVO 4 , [10][11][12] WO 3 , [13][14][15] and TiO 2 [16,17] as water oxidation photoanodes; Si [18,19] and Cu 2 O [20,21] as water reduction photocathodes; and cobalt phosphate [11,22] and Pt nanoparticles [23,24] as redox catalysts. However, most semiconductors retain inherent problems such as the short diffusion length of charge carriers, [25] high recombination rate, [26] and low charge separation efficiency.…”

Tailored Assembly of Molecular Water Oxidation Catalysts on Photoelectrodes for Artificial Photosynthesis

“…(f) Immobilization of POM OER catalysts on WO 3 by in situ incorporation upon electropolymerization of conducting polymers for efficient and stable solar water oxidation. Reproduced with permission from ref . Copyright 2018 American Chemical Society.…”

“…Electropolymerization is a simple method to deposit uniform polymeric thin films of various thicknesses in solution phase , . Our group recently reported that tetraruthenium polyoxometalate (RuPOM) OER catalysts can be co‐deposited on WO 3 photoanodes with various electropolymerized conducting polymers, such as polypyrrole (PPy), polyaniline (PANI), and 3,4‐polyethylenedioxythiophene (PEDOT) (Figure f) . The performance of WO 3 photoanodes can be remarkably improved only when co‐depositing PPy and RuPOM due to the desired energy level alignment for efficient charge transfer.…”

“…The stability issues can be classified as the following: (1) degradation of the LbL‐assembled film by electrochemical reactions on photoelectrodes and (2) detachment or delamination of the film. Nevertheless, we believe there will be many opportunities for non‐covalent, LbL approaches, because it has more flexibility in design and fabrication and also can be readily combined with other conventional approaches, such as doping,, defect engineering,, and heterojunction formation, , of an underlying photoelectrode, for the practical application of artificial photosynthesis.…”

The Energy Consumed by Electrochemical Molecular Machines as Self‐Sensor of the Reaction Conditions: Origin of Sensing Nervous Pulses and Asymmetry in Biological Functions

“…The sensing features of the reaction rate have been used from the very beginning of the electroanalytical methodologies (polarographic, voltammetric, chronoamperometric, etcetera) to determine the concentration of the analyte reacting either, directly on any non‐reactive electrode or indirectly through an enzyme or an catalyst adsorbed on the electrode …”