Efficient CO2 conversion to useful chemicals has attracted increasing attention for the past decades. Especially, the photocatalytic CO2 conversion has received significant interest in the potential to provide an alternative clean fuel in a sustainable manner using solar energy. Here we report a self-assembled, monopipyridine ruthenium complex with an aromatic ring and two cis-oriented chloride ions, on a plasmonic half-dome-shaped Au/TiO2 heterostructure for the visible light-driven CO2 conversion to formic acid. The plasmonic Au/TiO2 platform allows the ruthenium complex to run the catalytic cycle effectively in aqueous solutions under room temperature and ambient pressure. The plasmonic gold nanostructure generate hot electrons by surface plasmon resonance, and induce photothermal effect efficiently when visible light is emloyed. Moreover, the acidic electrolyte condition reduce energy demand of the most high energy requiring reaction step. As a result, the photocatalyst exhibits 12 times higher turnover frequency (1,200 h-1 at 450 W) and over 10-fold greater turnover number (~11,700) than the state-of-the-art ruthenium-based photocatalyst in similar envirionment. This ruthenium complex also exhibited a superior selectivity towards formic acid (&gt;94%), the highest to date. The fast reaction rate was determined to be obtained by proton-mediated low energy intermediate instead of molecular hydrogen insertion. Besides, the uninterchangeable cis-configuration of the ruthenium complex resulted in remarkable selectivity. The improved catalytic activities were studied by experimental and computational approaches, and this work demonstrates that the plasmon-enhanced photocatalytic CO2 conversion through the self-assembly of molecular catalysts is a promising strategy to produce useful resources utilizing the solar energy in a sustainable way.

Plasmonic CO2 conversion to formic acid by cis-Rubpy complex with high selectivity and rate under mild condition

254th National Meeting (2017)

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