Photocatalytic
CO2 reduction technology has engaged
significant attention due to its high efficiency, high selectivity,
and environmental friendliness. However, its application is severely
restrained by issues such as low separation efficiency of photogenerated
carriers and a limited light absorption range. This work proposes
an innovative MgCr2O4/MgIn2S4 magnesium-based spinel/spinel heterostructure photocatalyst
to improve the photocatalytic CO2 reduction efficiency
through the synergistic contributions of S-scheme heterojunction and
photothermal effect. On the one hand, the unique S-scheme charge transfer
mechanism enables the effective separation of photogenerated carriers.
On the other hand, the photothermal effect allows an accelerated charge
migration by increasing the reaction center temperature. Moreover,
the abundant oxygen vacancies serve as electron traps and CO2 adsorption sites, unifying reaction and adsorption sites and substantially
improving catalytic efficiency. Under UV–vis and UV–vis-NIR
illumination, the average CO yields of the MgCr2O4/MgIn2S4 composite are 8.03 and 15.62 μmol
g–1 h–1, respectively, greatly
higher than those of pure MgCr2O4 and MgIn2S4 samples. Furthermore, the fabricated photocatalyst
demonstrates excellent performance and structure stability. Therefore,
this work may offer a new strategy for designing efficient and stable
photocatalysts.