Multiple light scattering and nanotip effect of hierarchical sea urchin-like W18O49 boosting photocatalytic hydrolysis of ammonia borane

Abstract The morphology of catalysts is a key factor influencing their photocatalytic performance. Herein, we prepared three W18O49 photocatalysts with different morphologies of sea urchin (W18O49SU), nanorod (W18O49NR) and hollow sphere (W18O49HS), and evaluate their performances in photocatalytic hydrolysis of ammonia borane (AB). Remarkably, W18O49SU exhibited an impressive photocatalytic H2 production rate with the highest TOF of 53.1 min−1 under visible light, which is 10.4 and 7.5 times higher than those of W18O49HS and W18O49NR, respectively. The comprehensive characterizations and control experiments revealed that the unique sea urchin-like morphology enabled the strong light harvesting by multiple light scattering, fast separation of photogenerated charges and directional electron enrichment by nanotip effect, which collaboratively boost the photocatalytic activity. Moreover, the enhancement effect of sea urchin-like morphology is again approved well on Nb2O5 photocatalysts. This work opens a paradigm to synergistically improve light harvesting and charge separation efficiency through rational design of photocatalyst nanostructure.