Size-Dependent Activity of Palladium Nanoparticles: Efficient Conversion of CO2 into Formate at Low Overpotentials

作者：Rahaman Motiar; Dutta Abhijit; Broekmann Peter

来源：Chemsuschem, 2017, 10(8): 1733-1741.

DOI：10.1002/cssc.201601778

• electrochemistry
• formate
• nanoparticles
• palladium
• size effect

Remarkable size-dependent activity of palladium nanoparticles (PdNPs) towards formate production is evident at very low overpotentials (-0.1 to -0.5V vs. RHE). Size-selective PdNPs, chemically synthesized at sizes of 3.8-10.7nm, effected an electrochemical CO2 reduction reaction in aqueous 0.5m NaHCO3. The faradaic efficiency of formate production (FEformate) on 3.8nm PdNPs exceeded 86% at E=-0.1V versus RHE, whereas on 6.5nm PdNPs an even higher FEformate of 98% was observed. However, FEformate decreased for larger PdNPs. The superior efficiency towards formate production at low overpotentials is rationalized in terms of a changed catalytic pathway through PdH phases. The observed maximum in the formate efficiency for a mean particle size of about 6.5nm is discussed in terms of counterbalancing the size-dependent effects of a competing CO2 reduction reaction and a parasitic hydrogen evolution reaction. Production rates of formate are also remarkably high at -0.3V versus RHE with 539.9 and 452.3ppmh(-1)mg(Pd)(-1) for the 6.5 and 3.8nm PdNPs, respectively.

• 出版日期2017-4-22