Abstract
The development of improved catalysts for the hydrogenation of CO2 into methane is a sustainable response to the energy crisis and environmental problems at the global level. Mn-Ce/N-TiO2 heterojunctions, comprising a Mn-Ce concretion composite, were prepared using a sol–gel technique, and the photocatalytic hydrogenation of CO2 was studied using visible light as alternative driving energy. The photocatalyst composite was characterized, and synergistic effects on the photocatalytic hydrogenation of CO2 into methane were investigated. The characterization results confirmed that there was a considerable shifting of band-gap energy towards the visible range with required properties, which enhances photocatalytic activities under natural sunlight. Carbon dioxide hydrogenation and its potential for conversion into methane was evaluated using a specially designed photoreactor and different light sources. The results show a CO2 hydrogenation rate of about 16.8% ±0.2 in a visible light-assisted catalytic reduction process in 60 min. The irradiation time and light source were studied and significant impacts on CO2 hydrogenation were observed under a LED light source and with H2O vapor as a reducing agent (up to 23.4% ± 0.2). The effect of photocatalysis on the methane yield in the anaerobic digestion (biomethanation) process was evaluated and a potential methane yield of up to 13.5% within 24 h was observed. The results suggested promising and sustainable applications of the Mn-Ce/N-TiO2 heterojunction composite for CO2 hydrogenation and for the conversion of CO2 into fuel and methane in the biomethanation process.
Original language | English |
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Pages (from-to) | 189-201 |
Number of pages | 13 |
Journal | Biofuels, Bioproducts and Biorefining |
Volume | 15 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1 Jan 2021 |
Keywords
- CO
- Mn-Ce/N-TiO composite
- biomethanation
- heterojunction
- methane
- sol–gel technique