Porphyrin-Modified Cobalt Sulfide As A Developed Noble Metal-Free Photoelectrocatalyst Toward Methanol Oxidation Under Visible Light

Designing noble metal-free electrocatalysts with highly efficient performance toward methanol oxidation reaction (MOR) still remains a significant challenge. Herein, 5,10,15,20-tetrakis(4-carboxylphenyl) porphyrin (TCPP) was used as a photosensitive organic molecule to modify cobalt sulfide (CoS) nanosheets, which exhibit a higher catalytic activity toward MOR than pure CoS under visible irradiation. Photoluminescence emission spectra and UV-vis diffuse reflectance spectra (DRS) reveal the catalytic mechanism from the synergetic effect from porphyrin molecules and CoS nanosheets because the recombinatation of photoelectrons and holes of the nanocomposites is remarkably inhibited and then electron transfer is accelerated. Notably, TCPP-CoS exhibits the high mass activity of 1240 mA mg(-1) for MOR irradiated by visible light, which is 1.43 times that of pure CoS. This work opens up a feasible and practical pathway for designing highly efficient noble metal-free MOR photoelectrocatalysts.