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Size‐Dependent Activity of Palladium Nanoparticles: Efficient Conversion of CO 2 into Formate at Low Overpotentials
Author(s) -
Rahaman Motiar,
Dutta Abhijit,
Broekmann Peter
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201601778
Subject(s) - formate , faraday efficiency , chemistry , catalysis , palladium , nanoparticle , inorganic chemistry , aqueous solution , particle size , electrochemistry , materials science , nanotechnology , electrode , organic chemistry
Remarkable size‐dependent activity of palladium nanoparticles (PdNPs) towards formate production is evident at very low overpotentials (−0.1 to −0.5 V vs. RHE). Size‐selective PdNPs, chemically synthesized at sizes of 3.8–10.7 nm, effected an electrochemical CO 2 reduction reaction in aqueous 0.5 m NaHCO 3 . The faradaic efficiency of formate production (FE formate ) on 3.8 nm PdNPs exceeded 86 % at E =−0.1 V versus RHE, whereas on 6.5 nm PdNPs an even higher FE formate of 98 % was observed. However, FE formate 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 6.5 nm is discussed in terms of counterbalancing the size‐dependent effects of a competing CO 2 reduction reaction and a parasitic hydrogen evolution reaction. Production rates of formate are also remarkably high at −0.3 V versus RHE with 539.9 and 452.3 ppm h −1 mg Pd −1 for the 6.5 and 3.8 nm PdNPs, respectively.