Hydrogen (H2) production by using solar energy to split water has attracted great interest as the ideal source of renewable, carbon-neutral, and abundant fuel to replace our current nonrenewable energy source. Herein we present our investigations of synthesis and properties of molecular catalysts and nanomaterials based on the first-row transition metals, as well as their applications in electrocatalytic/photocatalytic hydrogen production and water oxidation. The initial molecular catalysts in these efforts were Cu(II) polypyridyl complexes which undergoes decomposition to form active CuO for water oxidation when pH &lt;12 while no heterogeneous materials were observed when pH &gt;12. As for photocatalysis, a series of metal complexes of Schiff bases (Co, Ni) were explored as H2 evolution catalysts in a photocatalytic system containing 1D semiconductor (CdS nanorods) as photosensitizer, Na2S and Na2SO3 as electron donors (Figure 1, left). Under optimal conditions, high photocatalytic activity for H2 production was observed under visible light (λ &gt; 420 nm), with an apparent quantum efficiency at ~58.3% and H2 evolution rate at ~815 µmol●h-1●mg-1. In addition, we explored the application nanostructured metal phosphides (Ni2P, CoP, MoP et. al.) for photocatalytic H2 production with CdS nanorods. Steady state photoluminescence (PL) spectra and time-resolved photoluminescence (TRPL) decay spectra were further investigated to reveal that fast electron transfer process occurs between the excited CdS nanorods and the cocatalysts. Finally, we constructed photoelectrochemical (PEC) cells for water splitting based on some of these novel catalysts (Figure 1, right). These low-cost metal complexes with excellent catalytic properties thus offer new opportunities for photocatalytic water splitting.

Noble-metal-free catalysts for hydrogen production and water oxidation: from molecular systems to nanomaterials

256th National Meeting (2018)

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