Ultrafine Ru nanoparticles on nitrogen-doped CNT arrays for HER: A CVD-based protocol achieving microstructure design and strong catalyst-support interaction

Abstract

Strong metal-support interactions (SMSIs) play a pivotal role in enhancing the catalytic activity and stability of supported metal catalysts in heterogeneous thermal catalysis, but construction of effective SMSIs remains challenging in electrocatalysis. As a ubiquitous and versatile support for electrocatalysts, carbon materials are generally too inert to generate SMSIs with the loaded metal active sites. We hereby report a CVD-based method to prepare Ru nanoparticles on arrays of oxygen- and nitrogen-doped CNTs grown on the fibers of carbon paper (Ru/ONCNT@CP). The SMSIs were manifested by electronic structure tuning of Ru nanoparticles and their partial embedment in the carbon support. The SMSIs result in optimized Gibbs free energy of H*, lowered energy barrier of H2O dissociation, and enhanced catalyst robustness. Combined with the hierarchical microstructure, high surface area and hydrophilic/aerophobic nature, the Ru/ONCNT@CP electrode displays excellent HER catalytic activity in 1 M KOH, requiring overpotentials of only 73, 180, and 252 mV to achieve current densities of 100, 500, and 800 mA cm−2, respectively. Moreover, the Ru/ONCNT@CP electrode exhibits outstanding stability, with negligible current decay after 120 h HER operation at 100 mA cm−2. This work features an effective and scalable approach for preparation of metal-loaded-carbon electrocatalysts with engineered microstructure and SMSIs.