Catalytic activity of MOF(2Fe/Co)/carbon aerogel for improving H2O2 and  OH generation in solar photo-electro-Fenton process

- The optimal nFe:nCo was 2:1 for forming specific interaction on MOF(2Fe/Co)/CA.
- MOF addition enhanced the ORR activity of CA, then increased the yield of H2O2.
- ecb− can be served as an efficient and pH-independent Fenton-like catalysts.
- 100% RhB and 85% DMP removal was reached in 45 min and 120 min, respectively.
- Enhanced catalytic mechanism of SPEF process with MOF(2Fe/Co)/CA was proposed.

A novel bifunctional MOF(2Fe/Co)/CA cathode with a high surface possessing area, and good electrocatalytic and photocatalytic activity, was proposed for the solar photo-electro-Fenton (SPEF) process. The optimal nFe: nCo ratio was 2:1 for successfully introducing MOF(2Fe/Co) on the surface of CA, which is due to the specific interaction affinity of FeOOH between MOF(2Fe/Co) and CA. Continuous on-site generation of H2O2 through an oxygen reduction reaction (ORR) was achieved over the CA cathode. The electron transfer number (n) of the ORR with CA was 2.5 in the selected potential range. Moreover, the addition of MOF can behave as the active sites for enhancing the ORR activity and hence can increase the yield of the H2O2. Simultaneously, the photoinduced electron (ecb−) of MOF(2Fe/Co) efficiently in-situ decomposed H2O2 to form hydroxyl radicals (OH). The observation indicated that the ecb− is an efficient and new Fenton-like catalysts that is pH-independent. Efficient photo-electro-catalytic performance was exhibited when applied to degrade Rhodamine B (RhB) and dimethyl phthalate (DMP). Almost 100% RhB removal and 85% DMP removal were reached in 45 min and 120 min, respectively. The MOF(Fe/Co)/CA presented very low iron and cobalt leaching (<0.5 ppm) even in an acidic media, and it retained an efficient degradation efficiency in the wide pH range of 3-9.

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