Solar-driven
CO
2 methanation is an imperative and promising approach to relieve
the global warming and environmental crisis, yet remains a great challenge due
to the low reaction efficiency, unsatisfactory selectivity and poor stability.
In this work, we demonstrate a facile and efficient strategy to prepare
Ru-doped TiO
2 photocatalyst with tunable oxygen vacancies using the
ascorbic acid as a reducing agent for the CO
2 methanation reaction.
The optimal Ru-TiO
2-OV-50 exhibits a remarkable CH
4 production rate of 81.7 mmol g
-1 h
-1 with a 100% CH
4 selectivity under a 1.5 W cm
-2 light illumination, which is
significantly higher than commercial Ru/TiO
2 and other reported
catalysts. We reveal that the superior photocatalytic CO
2 methanation performance is mainly due to the synergistic effect of Ru doping
and TiO
2 with tunable oxygen vacancies. Impressively, the light
rather than thermal effect is confirmed as the main influencing factor by
experimental studies. In addition,
in
situ spectroscopic technology is performed to investigate the CO
2 methanation reaction pathway. This work will open an avenue to design and
prepare highly efficient photocatalyst with tunable oxygen vacancies for CO
2 conversion and other related applications.