Na-Ru bimetallic functional sites promote photo-driven CO2 directed conversion into CH4

Recently, there has been a significant increase in interest in using photocatalysis for the energy conversion of polluting gases. In this research, sodium and ruthenium bimetallic functional sites co-modified bismuth tungstate (Ru/Na-Bi 2 WO 6 ) nanoflower photocatalyst was synthesized via the hydrothermal method. The CO 2 reduction products on the Bi 2 WO 6 substrate were CO (1.66 μmol/g/h, 68 %) and CH 4 (0.78 μmol/g/h, 32 %). After optimization, a significant change in the CO 2 products of the Bi 2 WO 6 -based composite material was observed, with CO (0.61 μmol/g/h, 3.6 %) and CH 4 (16.1 μmol/g/h, 96.4 %). Results showed that the dominance of CH 4 as the main product in the Ru/Na-BWO system is attributed to the effective doping of Na, which generates impurity energy levels composed of oxygen vacancies, lowering the conduction band position of Bi 2 WO 6 , thereby suppressing CO generation, and enhancing CH 4 selectivity by changing the CO 2 activation pathway. The remarkable performance is ascribed to the synergized adsorption and activation of CO 2 by the tandem Na + sites and Ru 0 sites. Specifically, the doped Na + sites play a major role in promoting the adsorption CO 2 molecules, while the Ru 0 sites play a dominant role in facilitating the activation of the intermediates.