Boosting visible-light driven solar-fuel production over g-C3N4/tetra(4-carboxyphenyl)porphyrin iron(III) chloride hybrid photocatalyst via incorporation with carbon dots

Developing highly efficient photocatalysts for solar-fuels production under visible-light irradiation is of great promise, but still remains a big challenge. In this work, we use g-C3N4 incorporated with carbon dots as the photosensitizer to couple with tetra(4-carboxyphenyl)porphyrin iron(III) chloride (FeTCPP) molecular catalyst. The obtained g-C3N4-C-0.05/FeTCPP hybrid photocatalyst exhibits high activity for the solar-fuels production of CO and H-2 under visible-light irradiation, with CO yield of 23.1 mmol/g and Hy yield of 71.1 mmol/g in 6 h. The enhanced mechanism has been studied by various techniques like photocurrent response, photoluminescence and mid-infrared femtosecond transient absorption. The presence of trace amount of carbon dots in the system can provide an alternative channel for the electron transfer, i.e., from g-C3N4 to FeTCPP via the CDs. Accordingly, the interfacial charge separation and electron transfer can be promoted, leading to enhanced photocatalytic performance of the g-C3N4-C-x/FeTCPP hybrid photocatalysts.