Experimental and first principle DFT comprehensions of metal and bimetal modified bismuth titanate for wastewater treatment and CO2 hydrogenation

Abstract

Incorporating copper (Cu) and silver (Ag) at the bismuth titanate (BT) surface was carried out via hydrolysis method followed by calcination at 700 °C. Modified BT further tested for the photodegradation of a recalcitrant pollutant Bisphenol-A (BPA), followed by the evaluation of photocatalytic hydrogenation of CO₂ for selective production of CO and CH₄. Photodegradation studies were remarkable in BT doped with both the metals (labelled “BTCA”) as compared to pristine BT and mono metal modified BT with Cu and Ag. In case of photocatalytic CO₂ hydrogenation, BTCA analyte demonstrated a proximal increase in CO₂ conversion efficiency, which enhanced up to 39.1% as compared to monometallic doped and pristine BT. CO was the primary product of CO₂ reduction, while CH₄ was also produced to a lesser level. As CH₄ selectivity increased, surface normalised CO₂ conversion rates declined. This result was attributed to the difference in the number of electrons required to convert CO₂ to CO or CH₄. In our previous work of pristine BT, methane selectivity was only 0.1–0.2% of the overall CO₂ conversion. Hence, present findings are based on the modification of BT with copper and silver, for the evaluation of electron transfer and abundance for enhanced selectivity for CH₄.