Efficient Photoelectrochemical O 2 and CO Production Using BiVO 4 Water Oxidation Photoanode and CO 2 Reduction Au Nanoparticle Cathode Prepared by In Situ Deposition from Au 3+ Containing Solution

• Published in: Advanced sustainable systems (Online) 2017-11, Vol.1 (11)
• Main Authors: Zahran, Zaki N., Mohamed, Eman A., Haleem, Ashraf Abdel, Naruta, Yoshinori
• Format: Article
• Language: English
• ISSN: 2366-7486; 2366-7486
• DOI: 10.1002/adsu.201700111

The cathodic polarization of various conducting electrodes in a CO 2 ‐saturated DMF/5% H 2 O solution containing AuCl 3 (DMF = N,N‐dimethylformamide) results in in situ deposition of a highly selective and efficient CO 2 to CO conversion Au nanoparticle electrocatalyst. These electrodes include glassy carbon, fluorine doped tin oxide (FTO), and Au plate. The efficiency of the Au nanoparticles is enhanced by introducing 1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate ionic liquid (EMI OTf IL, 10%) to the AuCl 3 ‐containing DMF/5% H 2 O deposition solution. In addition to the simplicity and novelty of the preparation method, the resultant in situ deposited Au nanoparticle cathode shows superior activity and selectivity for CO 2 to CO conversion compared to Au nanoparticles prepared by other techniques. Moreover, the in situ deposited Au nanoparticle electrode is used as a cathode in an n‐type photoelectrochemical cell with a water oxidation BiVO 4 photoanode modified with three‐layer water oxidation catalysts [FTO/EMI BiVO 4 /FeOOH/NiOOH/Co(bpy‐P) 2 , bpy‐P = 2,2′‐bipyridine‐4,4′‐diphosphonic acid] to achieve efficient solar‐assisted CO and O 2 production with 0.78% solar to CO conversion efficiency. The resultant 0.78% efficiency is the highest efficiency obtained toward CO 2 to CO conversion in PEC devices without any use of photovoltaic cell as a tandem.