ABSTRACT:
The photocatalytic reduction of CO2 with H2 over nickel (Ni) and indium (In) co-doped TiO2 nanocatalysts in a monolith photoreactor has been investigated. The structure and properties of catalysts, prepared via modified sol–gel method with different metal-doping levels, were characterized by XRD, SEM, TEM, N2 adsorption–desorption, XPS, UV–vis and PL spectrophotometry. Both nickel and indium, present over TiO2 as Ni2+ and In3+, promoted efficient separation of photo-generated charges (e/h+). The CO2 reduction efficiency was more significant for H2 compared to H2O vapors. TiO2 modified with 1.0 wt.% NiO and 3.5 wt.% In2O3 registered the highest CO yield. In a batch process, the maximum yield rate of CO over NiO–In2O3/TiO2 catalyst at 99.7% selectivity was 12,029 lmol g-catal.1 h1; 5.9 and 207 folds higher than In2O3/TiO2 and TiO2 catalysts, respectively. Similarly, CO2 conversion over NiO–In2O3/TiO2 (10.2%) was more substantial than In2O3/TiO2 (6.42%) and pure TiO2 (1.7%). In a continuous process, CO production rate was slightly decreased, but more CO2 was processed over the entire irradiation time.Significantly enhanced quantum efficiency of a monolith photoreactor over NiO–In2O3/TiO2 catalyst was observed compared to the cell reactor obviously due to greater mobility of charges with hindered recombination rate and higher photonic efficiency. The stability of NiO–In2O3/TiO2 catalyst was partially
reduced after several cyclic runs.
- Muhammad Tahir and Nor Aishah Saidina Amin (2016). Performance analysis of nanostructured NiO–In2O3_TiO2 catalyst for CO2 photoreduction with H2 in a monolith photoreactor Chemical Engineering Journal, 285, 635-649. DOI: https://doi.org/10.1016/j.cej.2015.10.033
