Heterostructured Sn/SnO2-x nanotube peapods with a strong plasmonic effect for photoelectrochemical water oxidation

Nonprecious metals with localized surface plasmon resonance (LSPR) are recognized as effective light harvesters owing to their merits of cost-effectiveness and tunable spectral response range. Herein, for the first time, we demonstrate a fascinating nonprecious metallic plasmonic photocatalyst Sn/SnO2-x with peapod-like hetero-nanostructures fabricated via an electrospinning-hydrogenation process. The hydrogenation gives rise to the simultaneous formation of metallic Sn nanoparticle peas and oxygen vacancies in SnO2 semiconductors. Metallic Sn generates unprecedented strong LSPR absorption in the visible light region, which significantly enhances the utilization of photon energies in a broad UV-vis region for the peapod-like Sn/SnO2-x hetero-nanostructure. In addition, the built-in semiconductor-metal Schottky junctions are of great benefit in promoting charge carrier separation and the oxygen vacancies are favorable for accelerating surface catalytic oxygen evolution reaction kinetics. As a result, the peapod-like Sn/SnO2-x hetero-nanostructure delivers an improved photoelectrochemical performance with a high photocurrent density of 245 mu A cm(-2) at 1.23 V versus the reversible hydrogen electrode (RHE), which is seven times higher than that of pristine SnO2. It is believed that the present work will deepen the comprehensive understanding of the LSPR effect from nonprecious metals and open up new opportunities for other solar energy-related areas.