3D TiO2/Cu Microrod Ru Electrocatalyst for Stable Alkaline HER

The catalyst is segmented into a hierarchical structure with Pt nanoparticles dispersed on TiO2 nanorods, which are in turn supported on a 3D porous substrate. This segmentation prevents Pt particle agglomeration by providing numerous dispersion sites and maintains catalytic activity over extended periods.

A composite material system is constructed combining Pt, TiO2, and a porous substrate (such as aluminum foam or conductive polymer). This composite structure leverages the high catalytic activity of Pt, the stability and dispersion capability of TiO2, and the mechanical stability of the substrate to achieve both high initial activity and long-term stability.

The catalyst employs a porous structure with controlled pore size and distribution that facilitates efficient gas-liquid-solid mass transport. The porous architecture allows hydrogen bubbles to form and detach easily from the catalyst surface, preventing bubble build-up and maintaining high current density operation without significant energy loss.

The catalyst transitions from a traditional 2D planar structure to a 3D hierarchical architecture, adding spatial dimensionality that enhances mass transport pathways. This dimensional change creates multiple escape routes for hydrogen bubbles and improves electrolyte access to active sites, thereby reducing bubble-induced energy losses at high current densities.

The catalyst structure is designed to be self-supporting and self-immobilizing through strong adhesion between TiO2 nanorods and the porous substrate, as well as through electrostatic and chemical interactions. This self-service mechanism eliminates the need for external binders, preserving all catalyst surface areas as active sites while maintaining stable immobilization on the substrate.

The harmful binder component is completely extracted from the catalyst system. Instead of using binder-based immobilization, the design relies on direct growth of TiO2 nanorods on the substrate and strong anchoring of Pt nanoparticles to TiO2 surfaces, removing the insulating layer that would otherwise block active sites and reduce catalyst effectiveness.