79
Another zinc catalyst, which is zinc phthalocyanine/carbon nitride nanosheets,
exhibited high efficiency in photoelectrocatalytic reduction of carbon dioxide under
visible light, whereas, at potential −1.0 V, it was found that the generated methanol
was the major product (2 μmol/L). This activity was resulted from the synergic
effect of the carbon nitride nanosheets (Zheng et al. 2019).
Finally, the grafting of cobalt (II) phthalocyanine on the core-shell Ni/NiO nanocomposite showed superior yield of methanol (~3641 μmol/g after 24 h under visible light irradiation) with conversion rate of ~152 μmol.g
−1
.h
−1
(Prajapati et al.
2019).
3.2.2 Photocatalytic Reduction of Carbon Dioxide Using
Homogenous Catalysts
Comparing with semiconductors heterogeneous catalysts, homogeneous catalysts
are serving via an alternative route for solar carbon dioxide fixation (Das and Wan
Daud, 2014). Whereas, the heterogeneous catalysts should accept multiple elections
during the photocatalytic process.
The photocatalytic reduction of carbon dioxide using pyridine as homogenous
catalyst under visible light (higher than 420 nm) irradiation was reported by Wang
et al. (2016). The reaction was achieved in aid of ruthenium phenanthroline complex photosensitizer. Methanol was the main product (960 μmol/L).
3.2.3 Photocatalytic Reduction of Carbon Dioxide Using Metal
Organic Frameworks
The catalytic activities of MOFs towards the reduction of carbon dioxide are based
on the type of metal ion and the organic ligands. The built structure based on both
of these components should achieve redox potential around −3.65 to produce methanol (Maina et al. 2017).
The first trials of the investigation of the activities of MOFs in the reduction of
carbon dioxide were based on their high surface area and the resulted sorption
features. The first trial was using zinc-based imidazolate MOF (ZIF-8), which
enhanced the photocatalytic activity of the Zn 2 GeO 4 rods by 62% towards the conversion of carbon dioxide into methanol. Such progress was attributed to the high
adsorption affinity of ZIF-8 towards the dissolved carbon dioxide in water (Liu
et al. 2013a).
Another type of imidazolate framework was investigated, but from a different
point of view, whereas, in Li et al. 2013, Li et al. found that copper-based imidazolate frameworks had gotten relatively high yield of methanol (~1713 μmol/g) upon
the photocatalytic reduction of carbon dioxide under visible light irradiation
3 Application of Metal Organic Frameworks in Carbon Dioxide Conversion to Methanol
Another zinc catalyst, which is zinc phthalocyanine/carbon nitride nanosheets,
exhibited high efficiency in photoelectrocatalytic reduction of carbon dioxide under
visible light, whereas, at potential −1.0 V, it was found that the generated methanol
was the major product (2 μmol/L). This activity was resulted from the synergic
effect of the carbon nitride nanosheets (Zheng et al. 2019).
Finally, the grafting of cobalt (II) phthalocyanine on the core-shell Ni/NiO nanocomposite showed superior yield of methanol (~3641 μmol/g after 24 h under visible light irradiation) with conversion rate of ~152 μmol.g
−1
.h
−1
(Prajapati et al.
2019).
3.2.2 Photocatalytic Reduction of Carbon Dioxide Using
Homogenous Catalysts
Comparing with semiconductors heterogeneous catalysts, homogeneous catalysts
are serving via an alternative route for solar carbon dioxide fixation (Das and Wan
Daud, 2014). Whereas, the heterogeneous catalysts should accept multiple elections
during the photocatalytic process.
The photocatalytic reduction of carbon dioxide using pyridine as homogenous
catalyst under visible light (higher than 420 nm) irradiation was reported by Wang
et al. (2016). The reaction was achieved in aid of ruthenium phenanthroline complex photosensitizer. Methanol was the main product (960 μmol/L).
3.2.3 Photocatalytic Reduction of Carbon Dioxide Using Metal
Organic Frameworks
The catalytic activities of MOFs towards the reduction of carbon dioxide are based
on the type of metal ion and the organic ligands. The built structure based on both
of these components should achieve redox potential around −3.65 to produce methanol (Maina et al. 2017).
The first trials of the investigation of the activities of MOFs in the reduction of
carbon dioxide were based on their high surface area and the resulted sorption
features. The first trial was using zinc-based imidazolate MOF (ZIF-8), which
enhanced the photocatalytic activity of the Zn 2 GeO 4 rods by 62% towards the conversion of carbon dioxide into methanol. Such progress was attributed to the high
adsorption affinity of ZIF-8 towards the dissolved carbon dioxide in water (Liu
et al. 2013a).
Another type of imidazolate framework was investigated, but from a different
point of view, whereas, in Li et al. 2013, Li et al. found that copper-based imidazolate frameworks had gotten relatively high yield of methanol (~1713 μmol/g) upon
the photocatalytic reduction of carbon dioxide under visible light irradiation
3 Application of Metal Organic Frameworks in Carbon Dioxide Conversion to Methanol