Modulating the surface microenvironment of metal oxide carriers is crucial yet challenging for enhancing the catalytic performance of Rh nanocatalysts in hydrogen production from ammonia borane hydrolysis (ABH). Herein, we developed a nitrogen-modified urchin-like TiO2 (N-U-TiO2) supported Rh nanoparticles (NPs) catalyst that demonstrated excellent performance in ABH for hydrogen generation. Characterization results revealed that nitrogen modification introduced abundant oxygenated groups, defects, and mesoporous structure in the carrier, which facilitated the generation of ultra-small and uniformly dispersed Rh nanoparticles, thereby controlling the exposure of active sites on the surface. Moreover, the abundant oxygen vacancies (O-v) created through nitrogen modification effectively adjusted the charge distribution and electronic energy levels around the TiO2 defect sites, promoting electron transfer from N-U-TiO2 to Rh nanoparticles, resulting in the formation of electron-rich Rh species. These electron-rich Rh species promoted the oxidative cleavage of O-H bonds during H2O dissociation. Consequently, the Rh/N-U-TiO2 catalyst exhibited a high turnover frequency of 721 min(-1) and good reusability in the ABH reaction, surpassing the performance of Rh/U-TiO2 and many other reported Rh-based catalysts. This morphology-mediated heteroatom doping approach serves as a valuable guideline for designing metal oxide-supported noble metal catalysts aimed at hydrogen evolution from ABH.
