Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr QDs (CPB) on NH -rich porous g-C N nanosheets (PCN) to construct the composite photocatalysts via N-Br chemical bonding. The 20 CPB-PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h g in acetonitrile/water for photocatalytic reduction of CO to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application.
Vacancy
engineering, that is, self-doping of vacancy in semiconductors,
has become a commonly used strategy to tune the photocatalytic performances.
However, there still lacks fundamental understanding of the role of
the vacancies in semiconductor materials. Herein, the g-C3N4 nanosheets with tunable nitrogen vacancies are prepared
as the photocatalysts for H2 evolution and CO2 reduction to CO. On the basis of both experimental investigation
and DFT calculations, nitrogen vacancies in g-C3N4 induce the formation of midgap states under the conduction band
edge. The position of midgap states becomes deeper with the increasing
of nitrogen vacancies. The g-C3N4 nanosheets
with the optimized density of nitrogen vacancies display about 18
times and 4 times enhancement for H2 evolution and of CO2 reduction to CO, respectively, as compared to the bulk g-C3N4. This is attributed to the synergistic effects
of several factors including (1) nitrogen vacancies cause the excitation
of electrons to midgap states below the conduction band edge, which
results in extension of the visible light absorption to photons of
longer wavelengths (up to 598 nm); (2) the suitable midgap states
could trap photogenerated electrons to minimize the recombination
loss of photogenerated electron–hole pairs; and (3) nitrogen
vacancies lead to uniformly anchored small Pt nanoparticles (1–2
nm) on g-C3N4, and facilitate the electron transfer
to Pt. However, the overintroduction of nitrogen vacancies generates
deeper midgap states as the recombination centers, which results in
deterioration of photocatalytic activities. Our work is expected to
provide new insights for fabrication of nanomaterials with suitable
vacancies for solar fuel generation.
Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr3 QDs (CPB) on NHx‐rich porous g‐C3N4 nanosheets (PCN) to construct the composite photocatalysts via N−Br chemical bonding. The 20 CPB‐PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h−1 g−1 in acetonitrile/water for photocatalytic reduction of CO2 to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr3 QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.