Photocatalytic conversion of CO2 into value-added hydrocarbon (methanol) with high selectivity over ZnS nanoparticles driven by 355-nm pulsed laser

The CO2 photoconversion over reduced graphene oxide based on Ag/TiO2 photocatalyst in an advanced meso-scale continuous-flow photochemical reactor

This study aims at examining the use of an advanced meso-scale continuous-flow photochemical reactor for the photocatalytic conversion of CO₂ with water into fuel over TiO₂ (P25), Ag/TiO₂, and Ag/TiO₂/RGO catalysts. The silver loaded photocatalysts were prepared by one-step process via hydrothermal method. The prepared photocatalysts were characterized by various characterization techniques in order to identify the morphological, chemical, physical, and optical properties. The photocatalytic activity of the as-prepared catalysts was firstly examined by the photoelectrochemical (PEC) measurements and secondly by the photocatalytic reduction of CO₂ in the proposed setup. Liquid products were analyzed using gas chromatography-mass spectrometry (GC-MS) and total organic carbon (TOC) techniques. It was found that the ternary composite revealed an outstanding performance towards CO₂ photocatalytic reduction, where its selectivity was directed towards methanol production. The incorporation of graphene nanosheets enhanced the photocatalytic reduction of CO₂ by 3.3 and 9.4 times compared with Ag/TiO₂ and bare TiO₂, respectively, using the proposed photochemical reactor in a continuous mode. This study sheds the light on a novel type of a photocatalytic reactor where CO₂ conversion over Ag/TiO₂/RGO ternary composite was evaluated. A meso-scale continuous-flow photochemical reactor.

Synthesis and characterization of Cu-Zn/TiO2 for the photocatalytic conversion of CO2 to methane

Different Cu-Zn/TiO₂ catalysts were synthesized by using the wet impregnation method. The prepared catalysts were used for the conversion of CO₂ into methane by photocatalysis. Various characterization techniques were used to observe the surface morphology, crystalline phase, Brunauer-Emmett-Teller (BET) surface area, presence of impregnated Cu and Zn, and functional group. Scanning electron microscope analysis showed spherical morphology, and slight agglomeration of catalyst particles was observed. BET analysis revealed that the surface area of the catalyst was decreased from 10 to 8.5 m²/g after impregnation of Cu and Zn over TiO₂ support. Synergetic effect of Cu and Zn over TiO₂ support (Cu_2.6/TiO₂, Zn_0.5/TiO₂ and Cu_2.6-Zn_0.5/TiO₂) and the effects of Cu loading (0, 1.8, 2.1, 2.6 and 2.9 wt%) were also investigated at different feed molar ratios of H₂/CO₂ (2:1 and 4:1). The Cu_2.6-Zn_0.5/TiO₂ catalyst showed a maximum conversion of 14.3% at a feed molar ratio of 4. The addition of Zn over the catalyst surface increased the conversion of CO₂ from 10% to 14.3% which might be due to synergy of Cu and Zn over TiO₂ support.