Application of Novel Calix[4]arene Metal-free Sensitizers in Dye-sensitized Photoelectrochemical Cells for Water Splitting

Polymer Networks Assembled by Ruthenium Catalysts for Enhanced Water Splitting Performance in Calixarene Dye-Sensitized Photoelectrochemical Cells

Metal-free photosensitizers for the construction of low-cost and eco-friendly dye-sensitized photoelectrochemical cells (DSPECs) have recently been greatly improved, but the optimization of water oxidation catalysts (WOCs) used in DSPECs based on metal-free dyes has received little attention. Herein, a series of polymer networks (RuTPA, RuCz, RuPr and RuTz) assembled by ruthenium WOCs (RuCHO) with various organic donors are constructed and combined with calixarene dyes to prepare DSPEC devices. The FTO|TiO2|C4BTP+RuTPA photoanode shows the best performance with 85 % Faraday efficiency for oxygen production and 477 μA cm-2 photocurrent density after 200 s chopping irradiation at 0 V vs. Ag/AgCl, one of the highest records among other reported dye-sensitized photoanodes. Compared to monomeric RuCHO, Ru-based polymers with lower Ru content have higher activity and stability due to their rapid electron transfer and anti-aggregation ability. Meanwhile, RuTPA loaded electrodes show better performance due to the lower overpotential of the water oxidation reaction caused by the higher electron donating ability of its donor. This pioneering work incorporates Ru polymer networks as WOCs into the calixarene-sensitized DSPEC system, which has significant potential as a highly efficient and stable photoelectrochemical water splitting device.

Water Oxidation Molecular Assemblies in Dye-Sensitized Photoelectrochemical Cell: An Overview

Dye-sensitized photoelectrochemical cells (DSPECs) are efficient and sustainable approaches for hydrogen production via water splitting, driven by solar energy. Recent advancements have focused on enhancing the performance and stability of photoanodes, which are critical for efficient water oxidation. Herein discussed are the latest innovations including the development of metal-free organic sensitizers, improved chromophore-catalyst assemblies, and core-shell structures. These advances lead to reduced electron-hole recombination, increased light absorption, and enhanced electron transfer efficiency. Pyridine-anchored sensitizers have shown superior stability compared to traditional carboxylate and phosphate anchors in water, while covalently linked chromophores and molecular catalysts provide long-term operational stability. Together, these improvements bring DSPEC technology closer to practical applications in green hydrogen production, addressing key challenges of energy efficiency, scalability, and system durability. These approaches could be explored further toward realizing cost-effective hydrogen production.